Mechanical stability of the CMS strip tracker measured with a laser alignment system

TL;DR

This paper reports on the mechanical stability of the CMS silicon strip tracker during operation, using a laser alignment system and particle tracks to measure displacements and temperature effects with micron-level precision.

Contribution

It introduces a dedicated laser alignment system for real-time monitoring of the tracker’s mechanical stability during LHC operations.

Findings

Tracker components moved less than 30 microns during stable operation.

Temperature changes caused displacements of about 2 microns per degree Celsius.

Displacements largely reverted when temperature was restored.

Abstract

The CMS tracker consists of 206 square meters of silicon strip sensors assembled on carbon fibre composite structures and is designed for operation in the temperature range from -25 to +25 degrees C. The mechanical stability of tracker components during physics operation was monitored with a few micron resolution using a dedicated laser alignment system as well as particle tracks from cosmic rays and hadron-hadron collisions. During the LHC operational period of 2011-2013 at stable temperatures, the components of the tracker were observed to experience relative movements of less than 30 microns. In addition, temperature variations were found to cause displacements of tracker structures of about 2 microns/degree C, which largely revert to their initial positions when the temperature is restored to its original value.

Full text

0.1 Introduction

The silicon strip tracker of the CMS experiment at the CERN LHC is designed to provide precise and efficient measurements of charged particle trajectories in a solenoidal magnetic field of 3.8\unitT with a transverse momentum accuracy of 1–10% in the range of 1–1000\GeVcin the central region [1]. It consists of five main subdetectors: the tracker inner barrel with inner disks (TIB and TID), the tracker outer barrel (TOB), and the tracker endcaps on positive and negative sides (TECP and TECM) [2, 3]. The silicon strip sensors have pitches varying from 80\mumat the innermost radial position of 20\cm, to 205\mumat the outermost radius of 116\cm, delivering a single-hit resolution between 10 and 50\mum[1]. As a general criterion, the position of the silicon modules has to be known to much better accuracy than this intrinsic resolution.

Silicon sensors exposed to a large radiation fluence require cooling, and the CMS tracker is designed to operate in a wide temperature range from $-25$ to $+25^{\circ}$C. The mechanical stability of the tracker components is ensured by the choice of materials and by an engineering design that tolerates the expected thermal expansion and detector displacements. These displacements have to be measured and accounted for in the form of alignment constants used in the track reconstruction.

The absolute alignment of individual silicon modules is performed with cosmic ray muons and tracks from hadron-hadron collisions collected during periods of commissioning or collision data taking [4, 5, 6]. A significant advance in the track-based alignment came with the introduction of a global $\chi^{2}$ algorithm that combines reconstruction of the track and alignment parameters [7]. This algorithm, implemented in the \MILLEPEDEpackage [8], was successfully used in various experiments at the LHC, HERA, and Tevatron. The actual accuracy of the track-based alignment depends on the number of objects requiring alignment and the size of the track sample.

The movement of the tracker components over much shorter time scales is monitored in the CMS experiment with an optical laser alignment system (LAS) [9]. Lasers were already used in the alignment of several silicon-based tracking detectors, for example, in the ALEPH [10], ZEUS [11], and AMS02 [12] experiments. Moreover, the CMS experiment also uses lasers for linking the tracker and muon subdetectors together in a common reference frame [13]. There is an alternative method of optical alignment based on the RasNiK system that was implemented, for example, in the CDF [14] and ATLAS [15] experiments. The RasNik system uses a conventional light source with coded mask, a lens, and a dedicated optical sensor. Both methods have similar performance, but lasers have some advantages for operation in the CMS tracker. First, the infrared laser light penetrates the silicon sensors, hence simplifying the alignment system. Second, the laser light produces a signal similar to ionizing particles that permits the use of the same radiation-hard silicon detectors employed for tracking, instead of dedicated sensors. Yet another method, implemented in the ATLAS experiment, is based on the laser frequency scanning interferometry [16].

The LAS of the CMS tracker is one of the largest laser-based alignment systems ever built in high-energy physics. Forty infrared laser beams illuminate a subset of 449 silicon modules, and monitor relative displacements of the TIB, TOB, and TEC subdetectors over a time interval of a few minutes with a stability of a few \mum[9]. Alignment with particle tracks and laser beams are complementary techniques and together they ensure the high quality of track reconstruction. While the track-based alignment is used to reconstruct the alignment constants of individual modules, the LAS identifies short-term displacements of large structures in order to exclude such periods from the offline analysis of the experimental data.

In this paper we describe the mechanical structure of the tracker and the LAS in detail. We review the alignment procedure of using laser beams and particle tracks. The measurements of the mechanical stability of the tracker components during the LHC data taking period in 2011–2013, as well as during the LHC long shutdown period spanning 2013–2014, are presented and discussed.

0.2 Mechanical design of the CMS tracker

The silicon strip tracker of the CMS detector is composed of 15 148 silicon strip detector modules with a total area of about 206\unitm2 and is described in Refs. [2, 3]. Below we discuss in more detail the components of the tracker that are relevant to the mechanical stability of the detector. The mechanical concept of the tracker is sketched in Figure 1. The CMS coordinate system has its origin at the centre of the detector with the $z$-coordinate along the LHC beam pipe, in the direction of the counterclockwise proton beam, and the horizontal $x$- and the vertical $y$-coordinates perpendicular to the beam (in the cylindrical system $r$ is the radial distance and $\varphi$ is the azimuth). The inner radii from 4.4 up to 15\cmare occupied by the silicon pixel detector, which is operated independently of the strip tracker. The silicon strip modules are mounted around the beam pipe at radii from 20\cmto 116\cminside a cylinder of 2.4\unitm in diameter and 5.6\unitm in length. The TIB extends in $z$ to $\pm$70\cmand in radius to 55\cm. It is composed of two half-length barrels with four detector layers, supplemented by three TID disks at each end. The TID disks are equipped with wedge-shaped silicon detectors with radial strips. The TOB surrounds the TIB+TID. It has an outer radius of 116\cm, ranges in $\abs{z}$ up to 118\cm, and consists of six barrel layers. In the barrel part of the tracker, the detector strips are oriented along the $z$-direction, except for the double-sided stereo modules in the first two layers of the TIB and TOB, where they are rotated at an angle of 100\unitmrad, providing reconstruction of the $z$-coordinate. The TECP and TECM cover the region $124<\abs{z}<282$\cmand $22.5<r<113.5$\cm. Each TEC is composed of nine disks, carrying up to seven rings of wedge-shaped silicon detectors with radial strips, similar to the TID. Rings 1, 2, and 5 are also equipped with stereo modules for reconstruction of the $r$-coordinate.

Each module of the silicon strip detector has one or two silicon sensors that are glued on carbon fibre (CF) frames together with a ceramic readout hybrid, with a mounting precision of 10\mum. Overall, there are 27 different module designs optimized for different positions in the tracker. The detector modules are mounted on substructures that are, in turn, mounted on the tracker subdetectors.

The TIB is split into two halves for the negative and positive $z$-coordinates allowing easy insertion into the TOB. The TIB substructures consist of 16 CF half-cylinders, or shells. The mounting accuracy of detector modules on the shells is about 20\mumin the shell plane. The modules are assembled in rows that overlap like roof tiles for better coverage and compensation for the Lorentz angle [3]. An aluminium cooling tube, with 0.3\mmwall thickness and 4$\times$1.5\unitmm2 rectangular profile is glued to the mounts of the detector modules. Each row has three modules on one cooling loop and each cooling pipe is connected at the edges of the shells to the circular collector pipe that gives extra rigidity to the whole TIB mechanical structure. The overall positional accuracy of the assembly of all shells is about 500\mum.

The TOB main structure consists of six cylindrical layers supported by four disks, two at the ends and two in the middle of the TOB structure. The disks are made of 2\mmthick CF laminate and are connected by cylinders at the inner and outer diameters. The cylinders are produced from 0.4\mmCF skins glued onto two sides of a 20\mmthick aramid-fibre honeycomb core. The detector modules are mounted on 688 substructures called rods. The rods are inserted into openings on the disks, such that each rod is supported by two disks. The accuracy of mounting the rods is about 140\mumin $r$-$\varphi$ and 500\mumin $z$. Each rod has 6 or 12 (for rods with double-sided modules) silicon modules mounted in a row. A 2\mmdiameter copper-nickel cooling pipe is attached to the CF frame of the rod. Each module is mounted on the rod with an accuracy of 30\mumby two precision inserts connected to the cooling pipes, and two springs.

Each TEC side consists of nine disks with 16 wedge-shaped substructures on each disk, called petals. Overall there are 144 petals with different layouts, depending on the disk location. The petals are made of CF skins with a honeycomb structure inside. The wedge-shaped detector modules are mounted on the petals with an accuracy of 20\mumusing four aluminium inserts that are connected to the cooling pipe. A titanium cooling pipe of about 7\unitm in length, 3.9\mmin diameter, with 0.25\mmwall thickness is integrated into the petal honeycomb structure and is bent to connect all heat sink inserts. The petals are mounted on the CF disks with a precision of 70\mum. All nine disks of each TEC are connected together with eight CF bars forming a rigid structure. These bars are also used to hold service cables and cooling pipes. The overall accuracy of the disks assembly in the TEC subdetector is about 150\mumin all coordinates.

The main support structure for all tracker subdetectors is the tracker support tube (TST). The TST is a cylinder 5.4\unitm in length and 2.4\unitm in diameter made of CF composite. The wall of the TST is made of a 30\mmthick sandwich structure with 2\mmCF skins on both sides, and a 26\mmthick aluminium honeycomb core. The TOB, TECP, and the TECM are supported inside the TST while the TIB and TID are supported by the TOB. The total weight of all subdetectors inside the TST is about 2200\unitkg, which is distributed on two longitudinal rails connected to the TST with glue and metallic inserts. The TST itself is supported inside the CMS calorimeters by four brackets at each end. According to calculations the maximum deformation of the TST when supporting the assembled tracker is about 0.6\mm. The mounting accuracy of different subdetectors inside the TST is in the range of 1\mm, but the exact position of all subdetectors was measured with an accuracy of 50\mumin an optical survey conducted at the beginning of the detector operation [5]. A possible movement that is beyond the assembly accuracy is considered as a major displacement.

The detector modules, substructures, and subdetectors are joined together using the so-called kinematic connections that constrain the movement in some directions, where the constraints are ensured by the static friction in tension screws. The engineering designs of these connections in the various mechanical structures are different, but the range in all joints suffices to accommodate the expected thermal movement. The fixation points and allowable movements for the subdetectors are indicated in Figure 1. In the vertical direction, each subdetector is constrained only by its own weight. The movement in the $x$-direction is constrained only on one side of the TST. The fixations in the $z$-coordinate are governed by the assembly procedure. During the assembly, the TOB was first inserted into the TST and fixed in $z$ on one side. Then the TIB and TID halves were inserted into the TOB from each end and fixed against each other in the centre. The TECP and TECM were mounted last, and constrained in $z$ at the internal ends.

Operation of silicon modules exposed to a large radiation fluence requires cooling [3]. The total dissipated power of the readout electronics with a fully powered tracker is about 45\unitkW. After irradiation the leakage current of the silicon sensors contributes another 10\unitkW. The heat inside the tracker is evacuated by a monophase liquid-cooling system that uses a fluorocarbon (C6F14) coolant. Two cooling plants, each with 40\unitkW capacity, are used for this purpose. Each plant is connected to 90 cooling loops distributed among the different substructures in one half of the tracker.

In the first physics run during 2010–2013 (Run 1), the operating temperature of the cooling plant was set to $\mathrm{T}=+4^{\circ}$C. For Run 2 (2015 onwards), the nominal operating temperature was decreased to $-15^{\circ}$C, in order to allow long term operation with increased fluence caused by increased energy of collisions, as well as instantaneous luminosity [3]. The operation at low-temperatures requires a low dew point inside the tracker. The whole tracker volume is separated from the TST inner wall by a thermal screen, apart from the points at which the subdetectors are attached to the rails that remain at ambient temperature. The thermal screen has cooling elements inside and heating elements outside the tracker volume, thus acting as a thermal barrier that prevents condensation. The inner tracker volume of about 25\unitm3 is constantly flushed with dry air or nitrogen at a rate of about 20\unitm3/hour, such that the dew point in the CMS cavern of about $+10^{\circ}$C is reduced to below $-40^{\circ}$C inside the tracker volume. All service cables and cooling pipes leave the subsystem at the tracker bulkheads, which are also isolated by the thermal screen and flushed with dry gas at a higher rate of about 150\unitm3/hour.

The temperature of the different mechanical structures inside the tracker depends on the distribution of heat sources and heat sinks. The temperature and humidity inside the tracker are monitored by dedicated sensors mounted directly on readout hybrids, silicon sensors, and mechanical structures, distributed throughout the detector volume. The nonuniformity of heat dissipation and heat removal results in significant temperature variations inside the tracker even in thermal equilibrium. Large temperature gradients are observed near the readout hybrids, the cooling tubes and the mounting connections. Figure 2 shows the temperature measured on silicon sensors in different subdetectors running with a cooling plant at operating temperature of $-5^{\circ}$C. The white areas represent non-operational detectors, which comprise about $2.5\%$ of the total area. The red (hot) spots are five cooling loops (three in the TIB, and one in the TOB and the TID) that are closed because of leaks and bad cooling contacts (layers L1, and L2 in the TIB).

A local change of temperature naturally causes an increase in the nonuniformity. For example, the powering of the module readout electronics rapidly increases the local temperature by about 15∘C and it takes about one hour to stabilize the temperature in the tracker volume. Cooling down from the ambient temperature of about $+15^{\circ}$C to $+4^{\circ}$C takes about 3 hours before stabilization of temperature.

0.3 The laser alignment system

The initial purpose of the LAS was to measure relative positions of the tracker subdetectors with an accuracy of about 10\mumand the absolute position with an accuracy of 100\mum. The large temperature variations expected in the tracker determined the design concept and components for the LAS; the components had to be light, radiation hard, operational in a high magnetic field, and capable of sustaining large temperature variations.

The LAS has 40 infrared laser beams that illuminate the silicon strip modules in the outer layer of the TIB, inner layer of the TOB, and in rings 4 and 6 of the TECs, as shown in Figure 3. The LAS uses the same detector modules that are used for particle detection. Laser pulses are triggered during the 3\musorbit gap corresponding to 119 missing bunches in the LHC beam structure that has an orbit time of 89\mus, thus not interfering with collisions [2]. The laser beams are split into two sets. Eight beams are used for global alignment of the TIB, TOB, and the TECs relative to each other. The other 32 beams are used to internally align the disks in the TECP and TECM subdetectors. The pixel and the TID subdetectors are not included in the LAS monitoring. Since the tracker has approximate axial symmetry, the beams are distributed rather uniformly in the $\varphi$-direction, with the exact position defined by the mechanical layout. Each laser beam used for global alignment illuminates six modules in the TIB, six modules in the TOB, and five modules in each of the TECP and TECM subdetectors. Each laser beam for the internal TEC alignment traverses nine modules in each TEC subdetector.

The LAS components include laser diodes, depolarizers, optical fibres, beam splitters, alignment tubes, mirrors, and specially treated silicon sensors. The laser diodes QFLD-1060-50S produced by QPhotonics have a wavelength of $\lambda=1075\pm$3.5\unitnm and a maximum optical power of 50\unitmW. The attenuation length of this laser light in silicon is 10\cmat $0^{\circ}$C and decreases by $1\%$/∘C with increasing temperature. The light output of each laser is regulated by an operating current in the range of 0–240\unitmA and is optimized as discussed below. The lasers operate in pulsed mode with a pulse width of 50\unitns. The spectral bandwidth of the lasers is $\Delta\lambda=2.4\pm 0.9$\unitnm, which defines the coherence length $\lambda^{2}/\Delta\lambda\approx 480\mum$. A coherence length larger than 2d$\cdot$nSi (where d is the silicon thickness of 320–500\mumand n${}_{\mathrm{Si}}\approx 3.5$ is the silicon refractive index) would result in interference of the laser light reflected on the front- and back-side of the sensor, hence degrading the laser beam profile. Because of the harsh radiation conditions in the CMS detector cavern, the laser diodes are located in the outer underground service area. The light is distributed to different subdetectors via special 0.125\mmdiameter Corning monomode optical fibres.

The light from the lasers is directed towards different subdetectors using beam splitters (BS) that divide the light into back-to-back beams, as shown in Figure 3. For the global alignment the eight beam splitters for the eight laser beams are mounted between the TOB and TECP. For the internal TEC alignment, 32 BS are located on disk 6 in both TECP and TECM. The principle of operation of the beam splitter is based on polarization using a $\lambda$-plate, as shown in Figure 4. The incoming beam, consisting of both $s$- (perpendicular to the plane of incidence) and $p$- (parallel) polarizations, is collimated onto a $45^{\circ}$ inclined surface with a special coating, from which the $s$-polarized part of the laser light is completely reflected. The $p$-fraction continues, traversing a $\lambda/4$-plate and converting into right circular polarization. The light is reflected by a mirror after the plate and changes polarization to left circular. After a second traversal of the $\lambda/4$-plate, the left circularly polarized light becomes $s$-polarized and is completely reflected onto the other side of the 45∘ inclined surface. At the end, there are two parallel back-to-back beams with $s$-polarization in the $z$-direction. The important characteristic of the splitter is the variation of collinearity as a function of the beam spot position. For all BS, the collinearity is measured to be less than 50\unit$\mu$rad for the $-25$ to $+25^{\circ}$C temperature range. Since the laser light is polarized, splitting based on a $\lambda$-plate requires depolarization. The depolarizers (produced by Phoenix Photonics) are located in the service area just after the laser diodes and before the optical fibres.

Dedicated alignment tubes (AT) between the TIB and TOB are used to hold the BS and semitransparent mirrors that reflect light towards TOB and TIB detector modules, as shown in Figure 4. The eight laser beams between TOB and TIB pass through the AT and continue to the TECM disks. The AT are made from 16\mmdiameter aluminium and are integrated into the TOB support wheels. The mirrors mounted inside the AT are glass plates that reflect about 5% of the light intensity perpendicular to the beam ($S_{1}$). The antireflective coating on the back side of the mirror and the $s$-polarization of the laser light after the beam splitter prevent the second reflection ($S_{2}$). The mounting accuracy of each AT is about 100\mum, but with temperature variations the aluminium can expand by about 0.5\unitmm/m/$20^{\circ}$C. Although this expansion is mostly along the $z$-direction, the movement can affect the orientation of the BS and therefore the direction of the laser beams. Such variations are taken into account in the LAS reconstruction procedure, as discussed below.

Overall the laser beams hit 449 silicon sensors, with a strip pitch varying from 120\mumin the TIB to 156\mumin the TEC detector modules. The 48 TIB and 48 TOB sensors that are used by the LAS are standard ones, and are illuminated on the strip side. On the other hand, 353 TEC sensors had to be modified to allow the passage of laser light. For the standard sensors, the backplane is covered with aluminium coating and is therefore not transparent to the laser light. For the TEC modules this coating was removed in a 10\mmdiameter circular area of the anticipated laser spot position. In addition, an antireflective coating was applied in this area in order to improve the transparency. An attempt also to coat the strip sides resulted in changes of the silicon sensor electrical properties and was therefore abandoned.

Since the detector modules illuminated by lasers are also used for particle tracking, their readout electronics is exactly the same as for other silicon strip modules in the tracker [3]. The signal from the silicon strips is processed in the analogue pipeline readout chip (APV25) [2], and transferred to the data acquisition (DAQ) by optical fibres. The analogue signal from the APV25 chip is digitized by the analogue-to-digital converters (ADC) located in the CMS underground service cavern, and is processed further similarly to physics data. The LAS-specific electronics include a trigger board that is synchronized with the CMS trigger system and the 40 laser drivers.

The trigger delay for each laser driver is tuned individually to ensure that the laser signals arrive at the detector module properly synchronized with the CMS readout sequence. The laser intensity is also optimized individually to account for losses in the optical components and attenuation in the TEC silicon sensors. The amplitude and time settings for each laser driver are defined in a special calibration run, during which the laser intensity and delays are scanned in small steps. There are five settings available for each laser, to be shared between up to 22 detector modules illuminated by the same laser beam. This results in some variations of the laser signal amplitude in different detectors.

One regular LAS acquisition step consists of 2000 triggers. The first 1000 triggers are optimized for the global alignment, whilst the other 1000 triggers are used for the internal alignment of both TECs. The lasers are triggered with five different settings delivering 200 suitable laser shots for each illuminated module. The signal-to-noise ratio for the 200 accumulated pulses is above 20, which is similar to the signal from particle tracks. The lasers are triggered in the orbit gap of every hundredth LHC beam cycle, corresponding to a rate of 100\unitHz and resulting in about 20\units per acquisition step. During normal data taking the acquisition interval was set to 5\unitminutes to achieve a good compromise between the time resolution of the LAS alignment and the stored data volume. Since the LAS electronics is deeply integrated into the CMS data acquisition, it works only when the tracker and the DAQ are operational and configured for a global physics run. Intervals between the runs, periods of testing, and technical stops are not covered by the LAS measurements.

0.4 Tracker alignment

The general tracker alignment procedure reflects the mechanical structure of the detector. The largest alignable objects are the tracker subdetectors, and the smallest ones are the silicon sensors. Each alignable object is considered as an independent and mechanically rigid body that can move and rotate in six degrees of freedom: three offsets ($\Delta x,\Delta y,\Delta z$) and three rotations ($Rx,Ry,Rz$) around the axes, as shown in Figure 1.

The alignment procedures used with particle tracks and the LAS data differ somewhat. In the LAS, the assembly accuracy and the mechanical stability of the optical components are about 100\mum, limiting the accuracy of absolute alignment to about 50\mum[9]. Relative displacements with respect to a reference position can be monitored using LAS data with a much better precision of a few \mum. However, the limited number of laser beams only allows the reconstruction of the relative displacement of large structures, such as the TOB, TIB, and the TECs, using some assumptions discussed below.

The alignment with tracks does not have the aforementioned limitations [6]. The cosmic ray muon and collision tracks are copiously measured in CMS and are used to derive the absolute alignment parameters in the CMS coordinate system down to individual detector modules. The number and distribution of tracks define the time interval and the accuracy of different alignment parameters in the track-based alignment. For example, the alignment of large structures, similar to the alignment with LAS, can be performed after a few hours of data taking. In the following we describe some aspects of the alignment procedures using the LAS data and particle tracks.

0.4.1 Alignment with the laser system

The LAS alignment procedure is based on a few assumptions. First, we assume that the LAS can measure only relative displacements of the laser beam profile with respect to some reference position. In this study all displacements are derived with respect to the TOB position because the TOB holds the alignment tubes and is directly connected to the TST. The offsets of laser beam profiles from the reference positions are thus used to calculate the variations of alignment parameters, not their absolute values. The relative alignment assumes that all tracker components, including the LAS elements, can move.

The second assumption concerns the definition of alignable objects and their parameters. The laser beams used for the global alignment allow the reconstruction of displacements of the TOB and TIB in $\Delta x$, $\Delta y$, and rotations $Rx$, $Ry$, $Rz$, while movement along the $z$-axis is not measured in the barrel due to the orientation of strips along $z$. The same laser beams in the TECP and TECM are used to reconstruct $\Delta x$, $\Delta y$ and $Rz$, while other parameters are not constrained due to the radial orientation of the TEC strips. In the LAS alignment procedure, each subdetector is considered as a rigid body and all deviations from this model are treated as systematic uncertainties.

Further, it is also assumed that the orientation of the laser beams can vary, for example, due to temperature variation in the alignment tube leading to small rotations of the beam splitters. The direction of each $i$th laser beam is parameterized by the two parameters: the offset $\alpha_{i}$, and slope $\beta_{i}$ in the $\varphi$-$z$ plane. These laser beam parameters are estimated from the LAS measurements together with other alignment parameters in one global fit. Note that the laser beams passing through the mirrors or through the silicon sensors may have some kinks, but these kinks are independent of the beam orientation. The assumption of the straightness of the laser beams implies that all of the optical components of the LAS have flat surfaces near the laser beam spot, such that small displacements of the LAS components do not affect the alignment parameters.

Under the above assumptions the LAS alignment procedure has two main steps: reconstruction of laser beam profiles and evaluation of alignment parameters. The laser profile is defined as an accumulated amplitude in ADC counts versus strip number within a module after 200 laser shots. The profile depends on the laser intensity, the silicon strip pitch and the width of the laser beam spot after propagation of laser light through beam splitters, mirrors, and silicon sensors (for TECs). Figure 5 shows beam profiles for different subdetectors obtained in two acquisition steps. The position of the laser beam spot is obtained from the intersection of the linear extrapolations of the profile at its half-maximum. The strip pitches for the illuminated TIB, TOB, and TEC modules are the 120, 122, and 128\mumrespectively. For the TOB and TIB the profiles are Gaussian-like, while for the TEC detectors, where the light passes through the silicon, the profiles show a diffraction pattern caused by reflections inside the silicon sensor.

The second step is the reconstruction of the alignment parameters with respect to the reference position in each illuminated module. The displacements of the beam position $\psi^{j}$ in detector module $j$ with respect to the reference position $\psi^{j}_{\text{ref}}$ are given by $\delta^{j}=\psi^{j}-\psi^{j}_{\text{ref}}$. These displacements $\delta^{j}$ are inputs to the $\chi^{2}=\Sigma{(\delta^{j}-\phi^{j}(\vec{p}))^{2}}/{\sigma_{j}^{2}}$, where $\phi(\vec{p})$ are the predicted displacements depending on the fit parameters $\vec{p}$: $\alpha_{i}$, $\beta_{i}$, $\Delta x$, $\Delta y$, $Rx$, $Ry$, $Rz$. For the $\chi^{2}$ minimization, the $\partial\chi^{2}/\partial p_{k}$ derivatives are linearized using the small-angle approximation. The system of linear equations is solved analytically using matrix inversion with respect to the parameters $p_{k}$. The LAS alignment procedure is flexible; some measurements or all measurements from a specific laser beam can be excluded from the fit, and the number of fit parameters can be varied, for example excluding rotations or offsets. These features were used to check the stability of the alignment procedure and systematic uncertainties. The results from different fit configurations agree within 10\mum.

The stability of the alignment parameters reconstructed with the LAS has been studied during periods (of a few weeks) of operation at a fixed temperature where we expect no real movements of the tracker components. The stability is defined as one standard deviation of the distribution of each alignment parameter. A summary of the LAS alignment parameters and their stability is presented in Table  0.4.1. The best stability of about 1\mumis obtained for the relative $\Delta x$ and $\Delta y$ displacements of the TIB. For the TECM profiles the stability worsens to 2–3\mumdue to larger distortion of the laser beam after passing through many mirrors.

0.4.2 Alignment with particle tracks

A detailed description of tracker alignment with tracks can be found in numerous publications, $\eg$ in Ref. [6] and references therein. One of the track-based alignment algorithms used in CMS is \MILLEPEDEII  [8]. The algorithm simultaneously reconstructs the track parameters $\vec{x}$ for each event and the alignment parameters $\vec{p}$ for each alignable object, and involves two steps. In the first step the ${\partial f}/{\partial x_{i}}$ and ${\partial f}/{\partial p_{k}}$ derivatives of the track model $f(\vec{x},\vec{p})$ with respect to the track and alignment parameters are calculated. These derivatives are stored in a matrix with the size of $(n_{\text{tracks}}n_{\text{trackpar}}+n_{\text{algnpar}})^{2}$, where $n_{\text{tracks}}$ is the number of selected tracks, $n_{\text{trackpar}}$ is the number of individual track parameters (four for propagation without magnetic field and five for propagation in the field), $n_{\text{algnpar}}$ is the number of alignment parameters. Then the corresponding system of linear equations is reduced in size using block matrix algebra and solved numerically [6].

The phase-space of particle tracks defines the sensitivity of the track-based alignment procedure to a particular alignment parameter. Two types of tracks can be used; tracks from collisions that originate in the detector centre, and tracks from cosmic rays that can cross the detector away from the interaction point. For the 2012 period, about 15$\times$106 collision tracks and 4$\times$106 cosmic ray tracks were used for the alignment. The track samples are split into separate periods in time that are used to calculate the alignment parameters for all detector modules. The intervals should be chosen such that, within each period, the operations do not vary significantly, but at the same time should provide sufficient statistics for the \MILLEPEDEprocedure. Usually, each interval corresponds to a few months of stable operation. The reconstruction accuracy of different alignment parameters in the track-based alignment depends on the number of selected tracks and on the location of the detector modules [6].

0.5 Tracker mechanical stability

The tracker mechanical structures have a hierarchy, and can be grouped as follows: subdetectors (TIB, TOB, TECs), substructures (shells, rods, petals), and individual detector modules. All these components can potentially move for different reasons and over different time scales. We distinguish between short-term variations, which occur over an interval of a few hours, and long-term variations, which occur over a period of a few days or months.

Temperature variation is expected to be the main source of movement in the tracker during physics operation. The thermal expansion of the CF composite used in the support structures is about 2.6$\times$10*-6*/∘C. For the 2.4\unitm long TOB this would result in displacements of about 60\mumfor $\Delta\mathrm{T}=10^{\circ}$C. Since the mechanical design of the tracker allows for thermal expansion, the temperature-related movements should be elastic, that is, the positions are restored when the temperature is restored to its original value. However, this process can be disrupted by the uncontrollable static friction in kinematic joints and the thermal expansion of power cables, cooling pipes, etc. that are integrated into the structures of the tracker. Many thermal cycles of the tracker can thus result in some nonelastic displacements and non-rigid body deformations.

The release of intrinsic stresses produced during assembly is another source of movement that can happen occasionally or be initiated by the temperature variations. Variations of the magnetic field, intervention in the CMS cavern and mechanical work during technical stops can also cause the movement of some CMS components and affect the tracker alignment. These movements, as well as nonelastic movements and deformations, are difficult to simulate in finite-element method models, thus making experimental measurements indispensable for validation of the mechanical design.

0.5.1 Long-term stability

The long-term stability of global alignment parameters reconstructed with the LAS data in the years 2011–2013 is shown in Figure 6 and in more detail in Figures 7–10. The alignment parameters of the TIB and TECs are calculated with respect to the TOB. Each point in the plots corresponds to one LAS acquisition step with an interval of 5 minutes, and the uncertainties are from the LAS global fit. Different parameters can overlap in Figure 6, but the range of variations during the whole period is clearly visible. The operating temperature of the cooling plants was set to $+4^{\circ}$C throughout the operation period, resulting in a temperature of about $+6^{\circ}$C in the return pipe, which is shown as the black line in the figures. The positive spikes in the temperature correspond to the occasional power down of the cooling plants, and the small negative spikes of about $2^{\circ}$C are due to switching off the low-voltage supplies to the detector modules. The stability of the internal TEC alignment parameters is similar and is not discussed in this paper.

The whole period of 2011–2013 can be split into different parts. Periods with no LAS data are due to either nonoperational global CMS DAQ or nonoperational tracker. Loss of data resulting from LAS problems was below 1$\%$ and related to the occasional powering down of the LAS electronics in the service area.

Most of the LAS data were collected during periods of operation at stable temperature inside the tracker volume. The alignment parameters of the TIB and TEC are remarkably stable; all variations in displacements are within ${\pm}10\mum$ for the TIB, ${\pm}20\mum$ for the TECP, and ${\pm}30\mum$ for the TECM. The expanded view of some typical parts shown in Figure 6 can be seen in Figure 7, for example the periods of operation at stable temperature for the TIB and TECM are presented in the upper plots.

Stable operation is often interrupted by transient periods when alignment parameters change by more than 10\mum(or 10\unit$\mu$rad) for TIB and 30\mum(30\unit$\mu$rad) for TECs during an interval of a few hours. All these periods are associated with temperature variations. The temperature can change rapidly due to occasional trips of cooling plants or, more often, due to a power trip affecting some detector modules. The powering down of the low voltages of the readout hybrids reduces the temperature locally by about $15^{\circ}$C. The actual temperature variations depend upon how fast the cooling or voltages are restored, while the observed variations of the alignment parameters depend on when the LAS acquisition was restarted. The bottom left plot in Figure 7 shows an example of the evolution of the TIB alignment parameters after a power trip, affecting the whole tracker. Power to the tracker was restored and the LAS data acquisition restarted after 30 minutes, thus the movement during these 30 minutes was not recorded. The observed evolution of the alignment parameters follows the temperature stabilization in the tracker volume, which takes about an hour. Similar effects can be observed during the powerdown of the cooling plants; in this case the expected temperature variations and, therefore, the observed displacements are bigger, as can be seen in the bottom-right plot in Figure 7. The periods with large transient variations of alignment parameters are excluded from physics analysis.

The long periods of data taking are separated by a few technical stops when the whole CMS detector is powered down. During this time the temperature in the tracker is not controlled and is close to the ambient temperature in the detector cavern. At the same time some mechanical work and intervention to the CMS detector can take place. Hence, after each of these technical stops a new reference position is used in the LAS alignment procedure described above.

The long-term evolution of the alignment parameters calculated with the LAS data is compared with the results obtained from the alignment with particle tracks in Figures 8–10. The alignment parameters for the 2012 period are calculated for ten intervals that correspond to the LAS periods with new reference positions. The \MILLEPEDEalignment configuration was similar to the configuration for the LAS measurements, that is, the TOB position was fixed, and the TIB and TEC subdetectors were considered as rigid bodies that can move with the same degrees of freedom as used in the LAS. Since \MILLEPEDEdelivers absolute alignment parameters based on measurements in many detector modules, whilst the LAS measures relative displacements and only for the illuminated modules, some differences between the parameters derived with the two different methods are expected. However the variations of the parameters in both measurements are similar and are within 30\mum(or 30\unit$\mu$rad), confirming the long-term mechanical stability of large structures of the tracker. The displacements below 30\mumcan have different origins; for example they could be related to deformations of other components of the CMS detector. Since all observed large transient variations in the alignment parameters coincide with the variations of the temperature in the tracker volume, a dedicated thermal model can be used in the future to predict displacements using solely the temperature measurements.

0.5.2 Stability during temperature variations

Large variations of alignment parameters correlated with the temperature were studied during the long shutdown of the LHC in 2013. The tracker alignment parameters were reconstructed when the tracker was cooled down from a target temperature of $+4$ to $-10^{\circ}$C, and then warmed up again. The evaluation of the TIB alignment parameters during temperature transitions from $+4$ to $-10^{\circ}$C in steps of $\Delta\mathrm{T}=5^{\circ}$C is shown in Figure 11. The periods without data are due to other CMS commissioning activities that prevented LAS operation. For all cooldown transitions the pattern of movements is rather similar; the parameters change monotonically with temperature. When cooled by $\Delta\mathrm{T}=5^{\circ}$C, the TIB $\Delta x$ increases by about 5\mum, $\Delta y$ decreases by 10\mum, and the detector rotates around the $y$-coordinate by about 20\unit$\mu$rad. This corresponds to temperature-related displacements of 1–2\mum/∘C. Some relaxation of the $Ry$ rotation is observed for the long period at 0∘C. Warming up eliminates most of the variations immediately, with some remaining residuals of about 20\mumthat were not followed up in this test due to other CMS activities.

The alignment parameters were also calculated with \MILLEPEDEusing tracks from cosmic ray muons, as shown in Figure 11. About 1.6$\times$103 and 4$\times$103 cosmic ray tracks were recorded for the $0^{\circ}$C and $-10^{\circ}$C cooling steps, respectively. The \MILLEPEDEconfiguration was similar to the long-term stability measurements described in the previous section. The reference position was taken at $0^{\circ}$C. Despite low statistics, both measurements are in reasonable agreement for all alignment parameters except for the $Ry$ rotation. This rotation was weakly constrained by cosmic ray tracks because during the shutdown only the central part of the muon system was used for the trigger.

0.6 Summary

The mechanical stability of the CMS tracker was successfully monitored during the period 2011–2013 using a dedicated laser alignment system and particle tracks from collisions and cosmic ray muons. During operation at stable temperatures, the variations of alignment parameters were less than 30\mum. Larger changes were found to be related to temperature variations caused by the occasional power trip of some modules or of the cooling plant. These temperature-related displacements of the tracker subdetectors are of the order of 2\mum/∘C and are largely eliminated when the temperature is restored to its original value.

The results presented in this study have been crucial for the CMS tracker operation in cold conditions. They have established that major mechanical displacements do not take place, and have shown the importance of monitoring the temperature within the detector volume. The observed behaviour of the tracker components under various conditions reported here provides guidance for future upgrades of the CMS tracking system.

Acknowledgements.

We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS institutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centres and personnel of the Worldwide LHC Computing Grid for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: the Austrian Federal Ministry of Science, Research and Economy and the Austrian Science Fund; the Belgian Fonds de la Recherche Scientifique, and Fonds voor Wetenschappelijk Onderzoek; the Brazilian Funding Agencies (CNPq, CAPES, FAPERJ, and FAPESP); the Bulgarian Ministry of Education and Science; CERN; the Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China; the Colombian Funding Agency (COLCIENCIAS); the Croatian Ministry of Science, Education and Sport, and the Croatian Science Foundation; the Research Promotion Foundation, Cyprus; the Secretariat for Higher Education, Science, Technology and Innovation, Ecuador; the Ministry of Education and Research, Estonian Research Council via IUT23-4 and IUT23-6 and European Regional Development Fund, Estonia; the Academy of Finland, Finnish Ministry of Education and Culture, and Helsinki Institute of Physics; the Institut National de Physique Nucléaire et de Physique des Particules / CNRS, and Commissariat à l’Énergie Atomique et aux Énergies Alternatives / CEA, France; the Bundesministerium für Bildung und Forschung, Deutsche Forschungsgemeinschaft, and Helmholtz-Gemeinschaft Deutscher Forschungszentren, Germany; the General Secretariat for Research and Technology, Greece; the National Scientific Research Foundation, and National Innovation Office, Hungary; the Department of Atomic Energy and the Department of Science and Technology, India; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Foundation, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Ministry of Science, ICT and Future Planning, and National Research Foundation (NRF), Republic of Korea; the Lithuanian Academy of Sciences; the Ministry of Education, and University of Malaya (Malaysia); the Mexican Funding Agencies (BUAP, CINVESTAV, CONACYT, LNS, SEP, and UASLP-FAI); the Ministry of Business, Innovation and Employment, New Zealand; the Pakistan Atomic Energy Commission; the Ministry of Science and Higher Education and the National Science Centre, Poland; the Fundação para a Ciência e a Tecnologia, Portugal; JINR, Dubna; the Ministry of Education and Science of the Russian Federation, the Federal Agency of Atomic Energy of the Russian Federation, Russian Academy of Sciences, the Russian Foundation for Basic Research and the Russian Competitiveness Program of NRNU MEPhI (M.H.U.); the Ministry of Education, Science and Technological Development of Serbia; the Secretaría de Estado de Investigación, Desarrollo e Innovación and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies (ETH Board, ETH Zurich, PSI, SNF, UniZH, Canton Zurich, and SER); the Ministry of Science and Technology, Taipei; the Thailand Center of Excellence in Physics, the Institute for the Promotion of Teaching Science and Technology of Thailand, Special Task Force for Activating Research and the National Science and Technology Development Agency of Thailand; the Scientific and Technical Research Council of Turkey, and Turkish Atomic Energy Authority; the National Academy of Sciences of Ukraine, and State Fund for Fundamental Researches, Ukraine; the Science and Technology Facilities Council, UK; the US Department of Energy, and the US National Science Foundation. Individuals have received support from the Marie-Curie programme and the European Research Council and EPLANET (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS programme of the Foundation for Polish Science, cofinanced from European Union, Regional Development Fund, the Mobility Plus programme of the Ministry of Science and Higher Education, the National Science Center (Poland), contracts Harmonia 2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, and 2015/19/B/ST2/02861, Sonata-bis 2012/07/E/ST2/01406; the Thalis and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF; the National Priorities Research Program by Qatar National Research Fund; the Programa Clarín-COFUND del Principado de Asturias; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); and the Welch Foundation, contract C-1845.

.7 The CMS Collaboration

**Yerevan Physics Institute, Yerevan, Armenia

** A.M. Sirunyan, A. Tumasyan \cmsinstskip**Institut für Hochenergiephysik, Wien, Austria

** W. Adam, E. Asilar, T. Bergauer, J. Brandstetter, E. Brondolin, M. Dragicevic, J. Erö, M. Flechl, M. Friedl, R. Frühwirth\cmsAuthorMark1, V.M. Ghete, M. Hoch, C. Hartl, N. Hörmann, J. Hrubec, M. Jeitler\cmsAuthorMark1, A. König, I. Krätschmer, D. Liko, T. Matsushita, I. Mikulec, D. Rabady, N. Rad, B. Rahbaran, H. Rohringer, J. Schieck\cmsAuthorMark1, J. Strauss, W. Waltenberger, C.-E. Wulz\cmsAuthorMark1 \cmsinstskip**Institute for Nuclear Problems, Minsk, Belarus

** O. Dvornikov, V. Makarenko, V. Mossolov, J. Suarez Gonzalez, V. Zykunov \cmsinstskip**National Centre for Particle and High Energy Physics, Minsk, Belarus

** N. Shumeiko \cmsinstskip**Universiteit Antwerpen, Antwerpen, Belgium

** S. Alderweireldt, E.A. De Wolf, X. Janssen, J. Lauwers, M. Van De Klundert, H. Van Haevermaet, P. Van Mechelen, N. Van Remortel, A. Van Spilbeeck \cmsinstskip**Vrije Universiteit Brussel, Brussel, Belgium

** S. Abu Zeid, F. Blekman, J. D’Hondt, N. Daci, I. De Bruyn, K. Deroover, S. Lowette, S. Moortgat, L. Moreels, A. Olbrechts, Q. Python, K. Skovpen, S. Tavernier, W. Van Doninck, P. Van Mulders, I. Van Parijs \cmsinstskip**Université Libre de Bruxelles, Bruxelles, Belgium

** H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, G. Fasanella, L. Favart, R. Goldouzian, A. Grebenyuk, G. Karapostoli, T. Lenzi, A. Léonard, J. Luetic, T. Maerschalk, A. Marinov, A. Randle-conde, T. Seva, C. Vander Velde, P. Vanlaer, D. Vannerom, R. Yonamine, F. Zenoni, F. Zhang\cmsAuthorMark2 \cmsinstskip**Ghent University, Ghent, Belgium

** A. Cimmino, T. Cornelis, D. Dobur, A. Fagot, M. Gul, I. Khvastunov, D. Poyraz, S. Salva, R. Schöfbeck, M. Tytgat, W. Van Driessche, E. Yazgan, N. Zaganidis \cmsinstskip**Université Catholique de Louvain, Louvain-la-Neuve, Belgium

** H. Bakhshiansohi, C. Beluffi\cmsAuthorMark3, O. Bondu, S. Brochet, G. Bruno, A. Caudron, S. De Visscher, C. Delaere, M. Delcourt, B. Francois, A. Giammanco, A. Jafari, M. Komm, G. Krintiras, V. Lemaitre, A. Magitteri, A. Mertens, M. Musich, K. Piotrzkowski, L. Quertenmont, M. Selvaggi, M. Vidal Marono, S. Wertz \cmsinstskip**Université de Mons, Mons, Belgium

** N. Beliy \cmsinstskip**Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil

** W.L. Aldá Júnior, F.L. Alves, G.A. Alves, L. Brito, C. Hensel, A. Moraes, M.E. Pol, P. Rebello Teles \cmsinstskip**Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

** E. Belchior Batista Das Chagas, W. Carvalho, J. Chinellato\cmsAuthorMark4, A. Custódio, E.M. Da Costa, G.G. Da Silveira\cmsAuthorMark5, D. De Jesus Damiao, C. De Oliveira Martins, S. Fonseca De Souza, L.M. Huertas Guativa, H. Malbouisson, D. Matos Figueiredo, C. Mora Herrera, L. Mundim, H. Nogima, W.L. Prado Da Silva, A. Santoro, A. Sznajder, E.J. Tonelli Manganote\cmsAuthorMark4, F. Torres Da Silva De Araujo, A. Vilela Pereira \cmsinstskip**Universidade Estadual Paulista a, Universidade Federal do ABC b, São Paulo, Brazil

** S. Ahujaa, C.A. Bernardesa, S. Dograa, T.R. Fernandez Perez Tomeia, E.M. Gregoresb, P.G. Mercadanteb, C.S. Moona, S.F. Novaesa, Sandra S. Padulaa, D. Romero Abadb, J.C. Ruiz Vargasa \cmsinstskip**Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria

** A. Aleksandrov, R. Hadjiiska, P. Iaydjiev, M. Rodozov, S. Stoykova, G. Sultanov, M. Vutova \cmsinstskip**University of Sofia, Sofia, Bulgaria

** A. Dimitrov, I. Glushkov, L. Litov, B. Pavlov, P. Petkov \cmsinstskip**Beihang University, Beijing, China

** W. Fang\cmsAuthorMark6 \cmsinstskip**Institute of High Energy Physics, Beijing, China

** M. Ahmad, J.G. Bian, G.M. Chen, H.S. Chen, M. Chen, Y. Chen\cmsAuthorMark7, T. Cheng, C.H. Jiang, D. Leggat, Z. Liu, F. Romeo, M. Ruan, S.M. Shaheen, A. Spiezia, J. Tao, C. Wang, Z. Wang, H. Zhang, J. Zhao \cmsinstskip**State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China

** Y. Ban, G. Chen, Q. Li, S. Liu, Y. Mao, S.J. Qian, D. Wang, Z. Xu \cmsinstskip**Universidad de Los Andes, Bogota, Colombia

** C. Avila, A. Cabrera, L.F. Chaparro Sierra, C. Florez, J.P. Gomez, C.F. González Hernández, J.D. Ruiz Alvarez, J.C. Sanabria \cmsinstskip**University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia

** N. Godinovic, D. Lelas, I. Puljak, P.M. Ribeiro Cipriano, T. Sculac \cmsinstskip**University of Split, Faculty of Science, Split, Croatia

** Z. Antunovic, M. Kovac \cmsinstskip**Institute Rudjer Boskovic, Zagreb, Croatia

** V. Brigljevic, D. Ferencek, K. Kadija, B. Mesic, T. Susa \cmsinstskip**University of Cyprus, Nicosia, Cyprus

** A. Attikis, G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis, H. Rykaczewski, D. Tsiakkouri \cmsinstskip**Charles University, Prague, Czech Republic

** M. Finger\cmsAuthorMark8, M. Finger Jr.\cmsAuthorMark8 \cmsinstskip**Universidad San Francisco de Quito, Quito, Ecuador

** E. Carrera Jarrin \cmsinstskip**Academy of Scientific Research and Technology of the Arab Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt

** A. Ellithi Kamel\cmsAuthorMark9, M.A. Mahmoud\cmsAuthorMark10*,\cmsAuthorMark11, A. Radi\cmsAuthorMark11,*\cmsAuthorMark12 \cmsinstskip**National Institute of Chemical Physics and Biophysics, Tallinn, Estonia

** M. Kadastik, L. Perrini, M. Raidal, A. Tiko, C. Veelken \cmsinstskip**Department of Physics, University of Helsinki, Helsinki, Finland

** P. Eerola, J. Pekkanen, M. Voutilainen \cmsinstskip**Helsinki Institute of Physics, Helsinki, Finland

** J. Härkönen, T. Järvinen, V. Karimäki, R. Kinnunen, T. Lampén, K. Lassila-Perini, S. Lehti, T. Lindén, P. Luukka, J. Tuominiemi, E. Tuovinen, L. Wendland \cmsinstskip**Lappeenranta University of Technology, Lappeenranta, Finland

** J. Talvitie, T. Tuuva \cmsinstskip**IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France

** M. Besancon, F. Couderc, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, C. Favaro, F. Ferri, S. Ganjour, S. Ghosh, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, I. Kucher, E. Locci, M. Machet, J. Malcles, J. Rander, A. Rosowsky, M. Titov \cmsinstskip**Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France

** A. Abdulsalam, I. Antropov, S. Baffioni, F. Beaudette, P. Busson, L. Cadamuro, E. Chapon, C. Charlot, O. Davignon, R. Granier de Cassagnac, M. Jo, S. Lisniak, P. Miné, M. Nguyen, C. Ochando, G. Ortona, P. Paganini, P. Pigard, S. Regnard, R. Salerno, Y. Sirois, T. Strebler, Y. Yilmaz, A. Zabi, A. Zghiche \cmsinstskip**Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS-IN2P3

** J.-L. Agram\cmsAuthorMark13, J. Andrea, A. Aubin, D. Bloch, J.-M. Brom, M. Buttignol, E.C. Chabert, N. Chanon, C. Collard, E. Conte\cmsAuthorMark13, X. Coubez, J.-C. Fontaine\cmsAuthorMark13, D. Gelé, U. Goerlach, J. Hosselet, A.-C. Le Bihan, D. Tromson, P. Van Hove \cmsinstskip**Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique des Particules, CNRS/IN2P3, Villeurbanne, France

** S. Gadrat \cmsinstskip**Université de Lyon, Université Claude Bernard Lyon 1, CNRS-IN2P3, Institut de Physique Nucléaire de Lyon, Villeurbanne, France

** S. Beauceron, C. Bernet, G. Boudoul, C.A. Carrillo Montoya, R. Chierici, C. Combaret, D. Contardo, B. Courbon, P. Depasse, H. El Mamouni, J. Fay, G. Galbit, S. Gascon, M. Gouzevitch, G. Grenier, B. Ille, F. Lagarde, I.B. Laktineh, M. Lethuillier, L. Mirabito, A.L. Pequegnot, S. Perries, A. Popov\cmsAuthorMark14, D. Sabes, V. Sordini, M. Vander Donckt, P. Verdier, S. Viret, Y. Zoccarato \cmsinstskip**Georgian Technical University, Tbilisi, Georgia

** T. Toriashvili\cmsAuthorMark15 \cmsinstskip**Tbilisi State University, Tbilisi, Georgia

** D. Lomidze \cmsinstskip**RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany

** R. Adolphi, C. Autermann, S. Beranek, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, A. Ostapchuk, M. Preuten, M. Rauch, F. Raupach, S. Schael, C. Schomakers, J. Schulz, A. Schultz von Dratzig , T. Verlage, B. Wittmer, M. Wlochal, V. Zhukov \cmsinstskip**RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany

** A. Albert, M. Brodski, E. Dietz-Laursonn, D. Duchardt, M. Endres, M. Erdmann, S. Erdweg, T. Esch, R. Fischer, A. Güth, M. Hamer, T. Hebbeker, C. Heidemann, K. Hoepfner, S. Knutzen, M. Merschmeyer, A. Meyer, P. Millet, S. Mukherjee, M. Olschewski, K. Padeken, T. Pook, M. Radziej, H. Reithler, M. Rieger, F. Scheuch, L. Sonnenschein, D. Teyssier, S. Thüer \cmsinstskip**RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany

** V. Cherepanov, G. Flügge, B. Kargoll, T. Kress, A. Künsken, J. Lingemann, T. Müller, A. Nehrkorn, A. Nowack, C. Pistone, O. Pooth, A. Stahl\cmsAuthorMark16 \cmsinstskip**Deutsches Elektronen-Synchrotron, Hamburg, Germany

** M. Aldaya Martin, T. Arndt, C. Asawatangtrakuldee, K. Beernaert, O. Behnke, U. Behrens, A.A. Bin Anuar, K. Borras\cmsAuthorMark17, A. Campbell, P. Connor, C. Contreras-Campana, F. Costanza, C. Diez Pardos, G. Dolinska, G. Eckerlin, D. Eckstein, T. Eichhorn, E. Eren, E. Gallo\cmsAuthorMark18, J. Garay Garcia, A. Geiser, A. Gizhko, J.M. Grados Luyando, A. Grohsjean, P. Gunnellini, A. Harb, J. Hauk, M. Hempel\cmsAuthorMark19, H. Jung, A. Kalogeropoulos, O. Karacheban\cmsAuthorMark19, M. Kasemann, J. Keaveney, C. Kleinwort, I. Korol, D. Krücker, W. Lange, A. Lelek, T. Lenz, J. Leonard, K. Lipka, A. Lobanov, W. Lohmann\cmsAuthorMark19, R. Mankel, I.-A. Melzer-Pellmann, A.B. Meyer, G. Mittag, J. Mnich, A. Mussgiller, E. Ntomari, J. Olzem, D. Pitzl, R. Placakyte, A. Raspereza, B. Roland, M.Ö. Sahin, P. Saxena, T. Schoerner-Sadenius, S. Spannagel, N. Stefaniuk, G.P. Van Onsem, R. Walsh, C. Wissing \cmsinstskip**University of Hamburg, Hamburg, Germany

** H. Biskop, V. Blobel, M. Centis Vignali, A.R. Draeger, T. Dreyer, E. Garutti, D. Gonzalez, J. Haller, M. Hoffmann, A. Junkes, R. Klanner, R. Kogler, N. Kovalchuk, T. Lapsien, I. Marchesini, D. Marconi, M. Matysek, M. Meyer, M. Niedziela, D. Nowatschin, F. Pantaleo\cmsAuthorMark16, T. Peiffer, A. Perieanu, J. Poehlsen, C. Scharf, P. Schleper, A. Schmidt, S. Schumann, J. Schwandt, H. Stadie, G. Steinbrück, F.M. Stober, M. Stöver, H. Tholen, D. Troendle, E. Usai, L. Vanelderen, A. Vanhoefer, B. Vormwald, J. Wellhausen \cmsinstskip**Institut für Experimentelle Kernphysik, Karlsruhe, Germany

** M. Abbas, M. Akbiyik, C. Amstutz, C. Barth, S. Baur, C. Baus, J. Berger, E. Butz, M. Casele, R. Caspart, T. Chwalek, F. Colombo, W. De Boer, A. Dierlamm, S. Fink, B. Freund, R. Friese, M. Giffels, A. Gilbert, P. Goldenzweig, D. Haitz, F. Hartmann\cmsAuthorMark16, S.M. Heindl, U. Husemann, I. Katkov, A. Kornmeyer,\cmsAuthorMark14, S. Kudella, H. Mildner, M.U. Mozer, Th. Müller, M. Plagge, G. Quast, K. Rabbertz, S. Röcker, F. Roscher, M. Schröder, I. Shvetsov, G. Sieber, H.J. Simonis, R. Ulrich, S. Wayand, M. Weber, T. Weiler, S. Williamson, C. Wöhrmann, R. Wolf \cmsinstskip**Institute of Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece

** G. Anagnostou, G. Daskalakis, T. Geralis, V.A. Giakoumopoulou, A. Kyriakis, D. Loukas, I. Topsis-Giotis \cmsinstskip**National and Kapodistrian University of Athens, Athens, Greece

** S. Kesisoglou, A. Panagiotou, N. Saoulidou, E. Tziaferi \cmsinstskip**University of Ioánnina, Ioánnina, Greece

** I. Evangelou, G. Flouris, C. Foudas, P. Kokkas, N. Loukas, N. Manthos, I. Papadopoulos, E. Paradas \cmsinstskip**MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös Loránd University, Budapest, Hungary

** N. Filipovic, G. Pasztor \cmsinstskip**Wigner Research Centre for Physics, Budapest, Hungary

** G. Bencze, C. Hajdu, D. Horvath\cmsAuthorMark20, F. Sikler, V. Veszpremi, G. Vesztergombi\cmsAuthorMark21, A.J. Zsigmond \cmsinstskip**Institute of Nuclear Research ATOMKI, Debrecen, Hungary

** N. Beni, S. Czellar, J. Karancsi\cmsAuthorMark22, A. Makovec, J. Molnar, Z. Szillasi \cmsinstskip**Institute of Physics, University of Debrecen

** M. Bartók\cmsAuthorMark21, P. Raics, Z.L. Trocsanyi, B. Ujvari \cmsinstskip**Indian Institute of Science (IISc)

** J.R. Komaragiri \cmsinstskip**National Institute of Science Education and Research, Bhubaneswar, India

** S. Bahinipati\cmsAuthorMark23, S. Bhowmik\cmsAuthorMark24, S. Choudhury\cmsAuthorMark25, P. Mal, K. Mandal, A. Nayak\cmsAuthorMark26, D.K. Sahoo\cmsAuthorMark23, N. Sahoo, S.K. Swain \cmsinstskip**Panjab University, Chandigarh, India

** S. Bansal, S.B. Beri, V. Bhatnagar, R. Chawla, U.Bhawandeep, A.K. Kalsi, A. Kaur, M. Kaur, R. Kumar, P. Kumari, A. Mehta, M. Mittal, J.B. Singh, G. Walia \cmsinstskip**University of Delhi, Delhi, India

** Ashok Kumar, A. Bhardwaj, B.C. Choudhary, R.B. Garg, S. Keshri, S. Malhotra, M. Naimuddin, K. Ranjan, R. Sharma, V. Sharma \cmsinstskip**Saha Institute of Nuclear Physics, Kolkata, India

** R. Bhattacharya, S. Bhattacharya, K. Chatterjee, S. Dey, S. Dutt, S. Dutta, S. Ghosh, N. Majumdar, A. Modak, K. Mondal, S. Mukhopadhyay, S. Nandan, A. Purohit, A. Roy, D. Roy, S. Roy Chowdhury, S. Sarkar, M. Sharan, S. Thakur \cmsinstskip**Indian Institute of Technology Madras, Madras, India

** P.K. Behera \cmsinstskip**Bhabha Atomic Research Centre, Mumbai, India

** R. Chudasama, D. Dutta, V. Jha, V. Kumar, A.K. Mohanty\cmsAuthorMark16, P.K. Netrakanti, L.M. Pant, P. Shukla, A. Topkar \cmsinstskip**Tata Institute of Fundamental Research-A, Mumbai, India

** T. Aziz, S. Dugad, G. Kole, B. Mahakud, S. Mitra, G.B. Mohanty, B. Parida, N. Sur, B. Sutar \cmsinstskip**Tata Institute of Fundamental Research-B, Mumbai, India

** S. Banerjee, R.K. Dewanjee, S. Ganguly, M. Guchait, Sa. Jain, S. Kumar, M. Maity\cmsAuthorMark24, G. Majumder, K. Mazumdar, T. Sarkar\cmsAuthorMark24, N. Wickramage\cmsAuthorMark27 \cmsinstskip**Indian Institute of Science Education and Research (IISER), Pune, India

** S. Chauhan, S. Dube, V. Hegde, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, S. Sharma \cmsinstskip**Institute for Research in Fundamental Sciences (IPM), Tehran, Iran

** H. Bakhshiansohl, S. Chenarani\cmsAuthorMark28, E. Eskandari Tadavani, S.M. Etesami\cmsAuthorMark28, M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi\cmsAuthorMark29, F. Rezaei Hosseinabadi, B. Safarzadeh\cmsAuthorMark30, M. Zeinali \cmsinstskip**University College Dublin, Dublin, Ireland

** M. Felcini, M. Grunewald \cmsinstskip**INFN Sezione di Bari a, Università di Bari b, Politecnico di Bari c, Bari, Italy

** M. Abbresciaa**,b, C. Calabriaa**,b, C. Caputoa**,b, P. Cariolaa, A. Colaleoa, D. Creanzaa**,c, L. Cristellaa**,b, N. De Filippisa**,c, M. De Palmaa**,b, L. Fiorea, G. Iasellia**,c, G. Maggia**,c, M. Maggia, G. Minielloa**,b, S. Mya**,b, S. Nuzzoa**,b, A. Pompilia**,b, G. Pugliesea**,c, R. Radognaa**,b, A. Ranieria, G. Selvaggia**,b, A. Sharmaa, L. Silvestrisa**,\cmsAuthorMark16, R. Vendittia**,b, P. Verwilligena \cmsinstskip**INFN Sezione di Bologna a, Università di Bologna b, Bologna, Italy

** G. Abbiendia, C. Battilana, D. Bonacorsia**,b, S. Braibant-Giacomellia**,b, L. Brigliadoria**,b, R. Campaninia**,b, P. Capiluppia**,b, A. Castroa**,b, F.R. Cavalloa, S.S. Chhibraa**,b, G. Codispotia**,b, M. Cuffiania**,b, G.M. Dallavallea, F. Fabbria, A. Fanfania**,b, D. Fasanellaa**,b, P. Giacomellia, C. Grandia, L. Guiduccia**,b, S. Marcellinia, G. Masettia, A. Montanaria, F.L. Navarriaa**,b, A. Perrottaa, A.M. Rossia**,b, T. Rovellia**,b, G.P. Sirolia**,b, N. Tosia**,b,\cmsAuthorMark16 \cmsinstskip**INFN Sezione di Catania a, Università di Catania b, Catania, Italy

** S. Albergoa**,b, S. Costaa**,b, A. Di Mattiaa, F. Giordano*a**,b, R. Potenzaa**,b, A. Tricomia**,b, C. Tuvea**,*b \cmsinstskip**INFN Sezione di Firenze a, Università di Firenze b, Firenze, Italy

** G. Barbaglia, V. Ciullia**,b, C. Civininia, R. D’Alessandroa**,b, E. Focardia**,b, G. Latinoa**,b, P. Lenzia**,b, M. Meschinia, S. Paolettia, L. Russoa**,\cmsAuthorMark31, G. Sguazzonia, D. Stroma, L. Viliania**,b,\cmsAuthorMark16 \cmsinstskip**INFN Laboratori Nazionali di Frascati, Frascati, Italy

** L. Benussi, S. Bianco, F. Fabbri, D. Piccolo, F. Primavera\cmsAuthorMark16 \cmsinstskip**INFN Sezione di Genova a, Università di Genova b, Genova, Italy

** V. Calvellia**,b, F. Ferroa, M.R. Mongea**,b, E. Robuttia, S. Tosi*a**,*b \cmsinstskip**INFN Sezione di Milano-Bicocca a, Università di Milano-Bicocca b, Milano, Italy

** L. Brianzaa**,b,\cmsAuthorMark16, F. Brivioa**,b, V. Ciriolo, M.E. Dinardoa**,b, S. Fiorendia**,b,\cmsAuthorMark16, S. Gennaia, A. Ghezzia**,b, P. Govonia**,b, M. Malbertia**,b, S. Malvezzia, R.A. Manzonia**,b, D. Menascea, L. Moronia, M. Paganonia**,b, D. Pedrinia, S. Pigazzini*a**,b, S. Ragazzia**,b, T. Tabarelli de Fatisa**,*b \cmsinstskip**INFN Sezione di Napoli a, Università di Napoli ’Federico II’ b, Napoli, Italy, Università della Basilicata c, Potenza, Italy, Università G. Marconi d, Roma, Italy

** S. Buontempoa, N. Cavalloa**,c, G. De Nardo, S. Di Guidaa**,d,\cmsAuthorMark16, M. Espositoa**,b, F. Fabozzia**,c, F. Fiengaa**,b, A.O.M. Iorioa**,b, G. Lanzaa, L. Listaa, S. Meolaa**,d,\cmsAuthorMark16, P. Paoluccia**,\cmsAuthorMark16, C. Sciaccaa**,b, F. Thyssena \cmsinstskip**INFN Sezione di Padova a, Università di Padova b, Padova, Italy, Università di Trento c, Trento, Italy

** P. Azzia**,\cmsAuthorMark16, N. Bacchettaa, L. Benatoa**,b, D. Biselloa**,b, A. Bolettia**,b, R. Carlina**,b, P. Checchiaa, M. Dall’Ossoa**,b, P. De Castro Manzanoa, T. Dorigoa, U. Dossellia, F. Gasparinia**,b, S. Lacapraraa, M. Margonia**,b, G. Marona**,\cmsAuthorMark32, A.T. Meneguzzoa**,b, M. Michelottoa, F. Montecassianoa, J. Pazzinia**,b, N. Pozzobona**,b, P. Ronchesea**,b, F. Simonettoa**,b, E. Torassaa, M. Zanetti*a**,b, P. Zottoa**,b, G. Zumerlea**,*b \cmsinstskip**INFN Sezione di Pavia a, Università di Pavia b, Pavia, Italy

** A. Braghieria, D. Comottia**,b, F. De Canioa, F. Fallavollitaa**,b, A. Magnania**,b, P. Montagnaa**,b, B. Nodaria, S.P. Rattia**,b, V. Rea, C. Riccardia**,b, E. Riceputia, P. Salvinia, I. Vai*a**,b, P. Vituloa**,*b \cmsinstskip**INFN Sezione di Perugia a, Università di Perugia b, Perugia, Italy

** L. Alunni Solestizia**,b, G.M. Bileia, D. Ciangottinia**,b, L. Fanòa**,b, P. Laricciaa**,b, R. Leonardia**,b, G. Mantovania**,b, V. Mariania**,b, M. Menichellia, A. Sahaa, A. Santocchiaa**,b, L. Storchia \cmsinstskip**INFN Sezione di Pisa a, Università di Pisa b, Scuola Normale Superiore di Pisa c, Pisa, Italy

** K. Androsova**,\cmsAuthorMark31, P. Azzurria**,\cmsAuthorMark16, G. Bagliesia, J. Bernardinia, T. Boccalia, R. Castaldia, M.A. Cioccia**,\cmsAuthorMark31, R. Dell’Orsoa, S. Donatoa**,c, G. Fedi, A. Giassia, M.T. Grippoa**,\cmsAuthorMark31, F. Ligabuea**,c, T. Lomtadzea, L. Martinia**,b, A. Messineoa**,b, F. Morsania, F. Pallaa, A. Rizzia**,b, A. Savoy-Navarroa**,\cmsAuthorMark33, P. Spagnoloa, R. Tenchinia, G. Tonellia**,b, A. Venturia, P.G. Verdinia \cmsinstskip**INFN Sezione di Roma a, Università di Roma b, Roma, Italy

** L. Baronea**,b, F. Cavallaria, M. Cipriania**,b, D. Del Rea**,b,\cmsAuthorMark16, M. Diemoza, S. Gellia**,b, E. Longoa**,b, F. Margarolia**,b, B. Marzocchia**,b, P. Meridiania, G. Organtinia**,b, R. Paramattia, F. Preiatoa**,b, S. Rahatloua**,b, C. Rovellia, F. Santanastasio*a**,*b \cmsinstskip**INFN Sezione di Torino a, Università di Torino b, Torino, Italy, Università del Piemonte Orientale c, Novara, Italy

** N. Amapanea**,b, R. Arcidiaconoa**,c,\cmsAuthorMark16, S. Argiroa**,b, M. Arneodoa**,c, N. Bartosika, R. Bellana**,b, C. Biinoa, N. Cartigliaa, F. Cennaa**,b, M. Costaa**,b, R. Covarellia**,b, A. Deganoa**,b, N. Demariaa, L. Fincoa**,b, B. Kiania**,b, C. Mariottia, S. Masellia, E. Migliorea**,b, V. Monacoa**,b, E. Monteila**,b, M. Montenoa, M.M. Obertinoa**,b, L. Pachera**,b, N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia**,b, F. Raveraa**,b, A. Rivettia, A. Romeroa**,b, M. Ruspaa**,c, R. Sacchia**,b, K. Shchelinaa**,b, V. Solaa, A. Solanoa**,b, A. Staianoa, P. Traczyk*a**,*b \cmsinstskip**INFN Sezione di Trieste a, Università di Trieste b, Trieste, Italy

** S. Belfortea, M. Casarsaa, F. Cossuttia, G. Della Riccaa**,b, A. Zanettia \cmsinstskip**Kyungpook National University, Daegu, Korea

** D.H. Kim, G.N. Kim, M.S. Kim, S. Lee, S.W. Lee, Y.D. Oh, S. Sekmen, D.C. Son, Y.C. Yang \cmsinstskip**Chonbuk National University, Jeonju, Korea

** A. Lee \cmsinstskip**Chonnam National University, Institute for Universe and Elementary Particles, Kwangju, Korea

** H. Kim \cmsinstskip**Hanyang University, Seoul, Korea

** J.A. Brochero Cifuentes, T.J. Kim \cmsinstskip**Korea University, Seoul, Korea

** S. Cho, S. Choi, Y. Go, D. Gyun, S. Ha, B. Hong, Y. Jo, Y. Kim, K. Lee, K.S. Lee, S. Lee, J. Lim, S.K. Park, Y. Roh \cmsinstskip**Seoul National University, Seoul, Korea

** J. Almond, J. Kim, H. Lee, S.B. Oh, B.C. Radburn-Smith, S.h. Seo, U.K. Yang, H.D. Yoo, G.B. Yu \cmsinstskip**University of Seoul, Seoul, Korea

** M. Choi, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, G. Ryu, M.S. Ryu \cmsinstskip**Sungkyunkwan University, Suwon, Korea

** Y. Choi, J. Goh, C. Hwang, J. Lee, I. Yu \cmsinstskip**Vilnius University, Vilnius, Lithuania

** V. Dudenas, A. Juodagalvis, J. Vaitkus \cmsinstskip**National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia

** I. Ahmed, Z.A. Ibrahim, M.A.B. Md Ali\cmsAuthorMark34, F. Mohamad Idris\cmsAuthorMark35, W.A.T. Wan Abdullah, M.N. Yusli, Z. Zolkapli \cmsinstskip**Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico

** H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz\cmsAuthorMark36, A. Hernandez-Almada, R. Lopez-Fernandez, R. Magaña Villalba, J. Mejia Guisao, A. Sanchez-Hernandez \cmsinstskip**Universidad Iberoamericana, Mexico City, Mexico

** S. Carrillo Moreno, C. Oropeza Barrera, F. Vazquez Valencia \cmsinstskip**Benemerita Universidad Autonoma de Puebla, Puebla, Mexico

** S. Carpinteyro, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada \cmsinstskip**Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico

** A. Morelos Pineda \cmsinstskip**University of Auckland, Auckland, New Zealand

** D. Krofcheck \cmsinstskip**University of Canterbury, Christchurch, New Zealand

** P.H. Butler \cmsinstskip**National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan

** A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, W.A. Khan, A. Saddique, M.A. Shah, M. Shoaib, M. Waqas \cmsinstskip**National Centre for Nuclear Research, Swierk, Poland

** H. Bialkowska, M. Bluj, B. Boimska, T. Frueboes, M. Górski, M. Kazana, K. Nawrocki, K. Romanowska-Rybinska, M. Szleper, P. Zalewski \cmsinstskip**Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland

** K. Bunkowski, A. Byszuk\cmsAuthorMark37, K. Doroba, A. Kalinowski, M. Konecki, J. Krolikowski, M. Misiura, M. Olszewski, M. Walczak \cmsinstskip**Laboratório de Instrumentação e Física Experimental de Partículas, Lisboa, Portugal

** P. Bargassa, C. Beirão Da Cruz E Silva, B. Calpas, A. Di Francesco, P. Faccioli, P.G. Ferreira Parracho, M. Gallinaro, J. Hollar, N. Leonardo, L. Lloret Iglesias, M.V. Nemallapudi, J. Rodrigues Antunes, J. Seixas, O. Toldaiev, D. Vadruccio, J. Varela, P. Vischia \cmsinstskip**Joint Institute for Nuclear Research, Dubna, Russia

** S. Afanasiev, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavin, A. Lanev, A. Malakhov, V. Matveev\cmsAuthorMark38*,*\cmsAuthorMark39, V. Palichik, V. Perelygin, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, N. Voytishin, A. Zarubin \cmsinstskip**Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia

** L. Chtchipounov, V. Golovtsov, Y. Ivanov, V. Kim\cmsAuthorMark40, E. Kuznetsova\cmsAuthorMark41, V. Murzin, V. Oreshkin, V. Sulimov, A. Vorobyev \cmsinstskip**Institute for Nuclear Research, Moscow, Russia

** Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov, N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin \cmsinstskip**Institute for Theoretical and Experimental Physics, Moscow, Russia

** V. Epshteyn, V. Gavrilov, N. Lychkovskaya, V. Popov, I. Pozdnyakov, G. Safronov, A. Spiridonov, M. Toms, E. Vlasov, A. Zhokin \cmsinstskip**Moscow Institute of Physics and Technology, Moscow, Russia

** A. Bylinkin\cmsAuthorMark39 \cmsinstskip**P.N. Lebedev Physical Institute, Moscow, Russia

** V. Andreev, M. Azarkin\cmsAuthorMark39, I. Dremin\cmsAuthorMark39, M. Kirakosyan, A. Leonidov\cmsAuthorMark39, A. Terkulov \cmsinstskip**Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia

** A. Baskakov, A. Belyaev, E. Boos, M. Dubinin\cmsAuthorMark42, L. Dudko, A. Ershov, A. Gribushin, A. Kaminskiy\cmsAuthorMark43, V. Klyukhin, O. Kodolova, I. Lokhtin, I. Miagkov, S. Obraztsov, S. Petrushanko, V. Savrin \cmsinstskip**Novosibirsk State University (NSU), Novosibirsk, Russia

** V. Blinov\cmsAuthorMark44, Y.Skovpen\cmsAuthorMark44, D. Shtol\cmsAuthorMark44 \cmsinstskip**State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, Russia

** I. Azhgirey, I. Bayshev, S. Bitioukov, D. Elumakhov, V. Kachanov, A. Kalinin, D. Konstantinov, V. Krychkine, V. Petrov, R. Ryutin, A. Sobol, S. Troshin, N. Tyurin, A. Uzunian, A. Volkov \cmsinstskip**University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, Belgrade, Serbia

** P. Adzic\cmsAuthorMark45, P. Cirkovic, D. Devetak, M. Dordevic, J. Milosevic, V. Rekovic \cmsinstskip**Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain

** J. Alcaraz Maestre, M. Barrio Luna, E. Calvo, M. Cerrada, M. Chamizo Llatas, N. Colino, B. De La Cruz, A. Delgado Peris, A. Escalante Del Valle, C. Fernandez Bedoya, J.P. Fernández Ramos, J. Flix, M.C. Fouz, P. Garcia-Abia, O. Gonzalez Lopez, S. Goy Lopez, J.M. Hernandez, M.I. Josa, E. Navarro De Martino, A. Pérez-Calero Yzquierdo, J. Puerta Pelayo, A. Quintario Olmeda, I. Redondo, L. Romero, M.S. Soares \cmsinstskip**Universidad Autónoma de Madrid, Madrid, Spain

** J.F. de Trocóniz, M. Missiroli, D. Moran \cmsinstskip**Universidad de Oviedo, Oviedo, Spain

** J. Cuevas, J. Fernandez Menendez, I. Gonzalez Caballero, J.R. González Fernández, E. Palencia Cortezon, S. Sanchez Cruz, I. Suárez Andrés, J.M. Vizan Garcia \cmsinstskip**Instituto de Física de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain

** I.J. Cabrillo, A. Calderon, E. Curras, M. Fernandez, J. Garcia-Ferrero, G. Gomez, A. Lopez Virto, J. Marco, C. Martinez Rivero, F. Matorras, J. Piedra Gomez, T. Rodrigo, A. Ruiz-Jimeno, L. Scodellaro, N. Trevisani, I. Vila, R. Vilar Cortabitarte \cmsinstskip**CERN, European Organization for Nuclear Research, Geneva, Switzerland

** D. Abbaneo, E. Auffray, G. Auzinger, P. Baillon, A.H. Ball, D. Barney, G. Blanchot, P. Bloch, A. Bocci, J. Bonnaud, C. Botta, T. Camporesi, A. Caratelli, R. Castello, M. Cepeda, D. Ceresa, G. Cerminara, Y. Chen, K. Cichy, D. d’Enterria, A. Dabrowski, V. Daponte, A. David, M. De Gruttola, A. De Roeck, S. Detraz, E. Di Marco\cmsAuthorMark46, M. Dobson, O. Dondelewski, B. Dorney, T. du Pree, D. Duggan, M. Dünser, N. Dupont, A. Elliott-Peisert, P. Everaerts, F. Faccio, S. Fartoukh, G. Franzoni, J. Fulcher, W. Funk, T. Gadek, D. Gigi, K. Gill, M. Girone, F. Glege, D. Gulhan, S. Gundacker, M. Guthoff, P. Harris, J. Hegeman, V. Innocente, P. Janot, L. M. Jara Casas, J. Kaplon, J. Kieseler, H. Kirschenmann, V. Knünz, A. Kornmayer\cmsAuthorMark16, M.J. Kortelainen, K. Kousouris, M. Krammer\cmsAuthorMark1, C. Lange, P. Lecoq, P. Lenoir, C. Lourenço, M.T. Lucchini, S. Marconi, L. Malgeri, M. Mannelli, A. Martelli, S. Martina, F. Meijers, J.A. Merlin, S. Mersi, E. Meschi, S. Michelis, P. Milenovic\cmsAuthorMark47, F. Moortgat, S. Morovic, M. Mulders, H. Neugebauer, S. Orfanelli, L. Orsini, L. Pape, S. Pavis, E. Perez, M. Peruzzi, A. Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, A. Racz, T. Reis, G. Rolandi\cmsAuthorMark48, P. Rose, M. Rovere, H. Sakulin, J.B. Sauvan, C. Schäfer, C. Schwick, M. Seidel, A. Sharma, P. Silva, P. Sphicas\cmsAuthorMark49, J. Steggemann, M. Stoye, Y. Takahashi, M. Tosi, D. Treille, A. Triossi, A. Tsirou, V. Veckalns\cmsAuthorMark50, G.I. Veres\cmsAuthorMark21, B. Verlaat, M. Verweij, N. Wardle, H.K. Wöhri, A. Zagozdzinska\cmsAuthorMark37, W.D. Zeuner, L. Zwalinski \cmsinstskip**Paul Scherrer Institut, Villigen, Switzerland

** W. Bertl, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski, U. Langenegger, T. Rohe \cmsinstskip**Institute for Particle Physics, ETH Zurich, Zurich, Switzerland

** F. Bachmair, L. Bäni, P. Berger, L. Bianchini, B. Casal, G. Dissertori, M. Dittmar, M. Donegà, C. Grab, C. Heidegger, D. Hits, J. Hoss, G. Kasieczka, W. Lustermann, B. Mangano, M. Marionneau, P. Martinez Ruiz del Arbol, M. Masciovecchio, M.T. Meinhard, D. Meister, F. Micheli, P. Musella, F. Nessi-Tedaldi, F. Pandolfi, J. Pata, F. Pauss, G. Perrin, L. Perrozzi, M. Quittnat, M. Rossini, M. Schönenberger, A. Starodumov\cmsAuthorMark51, V.R. Tavolaro, K. Theofilatos, R. Wallny, D. Zhu \cmsinstskip**Universität Zürich, Zurich, Switzerland

** T.K. Aarrestad, C. Amsler\cmsAuthorMark52, K. Bösiger, L. Caminada, M.F. Canelli, A. De Cosa, C. Galloni, A. Hinzmann, T. Hreus, B. Kilminster, R. Maier, J. Ngadiuba, D. Pinna, G. Rauco, P. Robmann, D. Salerno, C. Seitz, Y. Yang, A. Zucchetta \cmsinstskip**National Central University, Chung-Li, Taiwan

** V. Candelise, T.H. Doan, Sh. Jain, R. Khurana, M. Konyushikhin, C.M. Kuo, W. Lin, A. Pozdnyakov, S.S. Yu \cmsinstskip**National Taiwan University (NTU), Taipei, Taiwan

** Arun Kumar, P. Chang, Y.H. Chang, Y. Chao, K.F. Chen, P.H. Chen, F. Fiori, W.-S. Hou, Y. Hsiung, Y.F. Liu, R.-S. Lu, M. Miñano Moya, E. Paganis, A. Psallidas, J.f. Tsai \cmsinstskip**Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand

** B. Asavapibhop, G. Singh, N. Srimanobhas, N. Suwonjandee \cmsinstskip**Cukurova University - Physics Department, Science and Art Faculty

** A. Adiguzel, S. Cerci\cmsAuthorMark53, S. Damarseckin, Z.S. Demiroglu, C. Dozen, I. Dumanoglu, S. Girgis, G. Gokbulut, Y. Guler, I. Hos\cmsAuthorMark54, E.E. Kangal\cmsAuthorMark55, O. Kara, A. Kayis Topaksu, U. Kiminsu, M. Oglakci, G. Onengut\cmsAuthorMark56, K. Ozdemir\cmsAuthorMark57, D. Sunar Cerci\cmsAuthorMark53, B. Tali\cmsAuthorMark53, S. Turkcapar, I.S. Zorbakir, C. Zorbilmez \cmsinstskip**Middle East Technical University, Physics Department, Ankara, Turkey

** B. Bilin, S. Bilmis, B. Isildak\cmsAuthorMark58, G. Karapinar\cmsAuthorMark59, M. Yalvac, M. Zeyrek \cmsinstskip**Bogazici University, Istanbul, Turkey

** E. Gülmez, M. Kaya\cmsAuthorMark60, O. Kaya\cmsAuthorMark61, E.A. Yetkin\cmsAuthorMark62, T. Yetkin\cmsAuthorMark63 \cmsinstskip**Istanbul Technical University, Istanbul, Turkey

** A. Cakir, K. Cankocak, S. Sen\cmsAuthorMark64 \cmsinstskip**Institute for Scintillation Materials of National Academy of Science of Ukraine, Kharkov, Ukraine

** B. Grynyov \cmsinstskip**National Scientific Center, Kharkov Institute of Physics and Technology, Kharkov, Ukraine

** L. Levchuk, P. Sorokin \cmsinstskip**University of Bristol, Bristol, United Kingdom

** R. Aggleton, F. Ball, L. Beck, J.J. Brooke, D. Burns, E. Clement, D. Cussans, H. Flacher, J. Goldstein, M. Grimes, G.P. Heath, H.F. Heath, J. Jacob, L. Kreczko, C. Lucas, D.M. Newbold\cmsAuthorMark65, S. Paramesvaran, A. Poll, T. Sakuma, S. Seif El Nasr-storey, D. Smith, V.J. Smith \cmsinstskip**Rutherford Appleton Laboratory, Didcot, United Kingdom

** K.W. Bell, A. Belyaev\cmsAuthorMark66, C. Brew, R.M. Brown, L. Calligaris, D. Cieri, D.J.A. Cockerill, J.A. Coughlan, K. Harder, S. Harper, E. Olaiya, D. Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, T. Williams \cmsinstskip**Imperial College, London, United Kingdom

** M. Baber, R. Bainbridge, O. Buchmuller, A. Bundock, D. Burton, S. Casasso, M. Citron, D. Colling, L. Corpe, P. Dauncey, G. Davies, A. De Wit, M. Della Negra, R. Di Maria, P. Dunne, A. Elwood, D. Futyan, Y. Haddad, G. Hall, G. Iles, T. James, R. Lane, C. Laner, R. Lucas\cmsAuthorMark65, L. Lyons, A.-M. Magnan, S. Malik, L. Mastrolorenzo, J. Nash, A. Nikitenko\cmsAuthorMark51, J. Pela, B. Penning, M. Pesaresi, D.M. Raymond, A. Richards, A. Rose, E. Scott, C. Seez, S. Summers, A. Tapper, K. Uchida, M. Vazquez Acosta\cmsAuthorMark67, T. Virdee\cmsAuthorMark16, J. Wright, S.C. Zenz \cmsinstskip**Brunel University, Uxbridge, United Kingdom

** J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, A. Morton, I.D. Reid, P. Symonds, L. Teodorescu, M. Turner \cmsinstskip**Baylor University, Waco, USA

** A. Borzou, K. Call, J. Dittmann, K. Hatakeyama, H. Liu, N. Pastika \cmsinstskip**Catholic University of America

** R. Bartek, A. Dominguez \cmsinstskip**The University of Alabama, Tuscaloosa, USA

** A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio, C. West \cmsinstskip**Boston University, Boston, USA

** D. Arcaro, A. Avetisyan, T. Bose, D. Gastler, D. Rankin, C. Richardson, J. Rohlf, L. Sulak, D. Zou \cmsinstskip**Brown University, Providence, USA

** G. Benelli, D. Cutts, A. Garabedian, J. Hakala, U. Heintz, J.M. Hogan, O. Jesus, K.H.M. Kwok, E. Laird, G. Landsberg, Z. Mao, M. Narain, J. Nelson, S. Piperov, S. Sagir, E. Spencer, J. Swanson, R. Syarif, D. Tersegno, J. Watson-Daniels \cmsinstskip**University of California, Davis, Davis, USA

** R. Breedon, D. Burns, M. Calderon De La Barca Sanchez, S. Chauhan, M. Chertok, J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, M. Gardner, W. Ko, R. Lander, C. Mclean, M. Mulhearn, D. Pellett, J. Pilot, S. Shalhout, M. Shi, J. Smith, M. Squires, D. Stolp, K. Tos, M. Tripathi \cmsinstskip**University of California, Los Angeles, USA

** M. Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M. Ignatenko, N. Mccoll, D. Saltzberg, C. Schnaible, V. Valuev, M. Weber \cmsinstskip**University of California, Riverside, Riverside, USA

** E. Bouvier, K. Burt, R. Clare, J. Ellison, J.W. Gary, S.M.A. Ghiasi Shirazi, G. Hanson, J. Heilman, P. Jandir, E. Kennedy, F. Lacroix, O.R. Long, M. Olmedo Negrete, M.I. Paneva, A. Shrinivas, W. Si, H. Wei, S. Wimpenny, B. R. Yates \cmsinstskip**University of California, San Diego, La Jolla, USA

** J.G. Branson, G.B. Cerati, S. Cittolin, M. Derdzinski, R. Gerosa, A. Holzner, D. Klein, V. Krutelyov, J. Letts, I. Macneill, D. Olivito, S. Padhi, M. Pieri, M. Sani, V. Sharma, S. Simon, M. Tadel, A. Vartak, S. Wasserbaech\cmsAuthorMark68, C. Welke, J. Wood, F. Würthwein, A. Yagil, G. Zevi Della Porta \cmsinstskip**University of California, Santa Barbara - Department of Physics, Santa Barbara, USA

** N. Amin, R. Bhandari, J. Bradmiller-Feld, C. Campagnari, A. Dishaw, V. Dutta, M. Franco Sevilla, C. George, F. Golf, L. Gouskos, J. Gran, R. Heller, J. Incandela, S.D. Mullin, A. Ovcharova, H. Qu, J. Richman, D. Stuart, I. Suarez, J. Yoo \cmsinstskip**California Institute of Technology, Pasadena, USA

** D. Anderson, J. Bendavid, A. Bornheim, J. Bunn, J. Duarte, J.M. Lawhorn, A. Mott, H.B. Newman, C. Pena, M. Spiropulu, J.R. Vlimant, S. Xie, R.Y. Zhu \cmsinstskip**Carnegie Mellon University, Pittsburgh, USA

** M.B. Andrews, T. Ferguson, M. Paulini, J. Russ, M. Sun, H. Vogel, I. Vorobiev, M. Weinberg \cmsinstskip**University of Colorado Boulder, Boulder, USA

** J.P. Cumalat, W.T. Ford, F. Jensen, A. Johnson, M. Krohn, S. Leontsinis, T. Mulholland, K. Stenson, S.R. Wagner \cmsinstskip**Cornell University, Ithaca, USA

** J. Alexander, J. Chaves, J. Chu, S. Dittmer, K. Mcdermott, N. Mirman, G. Nicolas Kaufman, J.R. Patterson, A. Rinkevicius, A. Ryd, L. Skinnari, L. Soffi, S.M. Tan, Z. Tao, J. Thom, J. Tucker, P. Wittich, M. Zientek \cmsinstskip**Fairfield University, Fairfield, USA

** D. Winn \cmsinstskip**Fermi National Accelerator Laboratory, Batavia, USA

** S. Abdullin, M. Albrow, G. Apollinari, A. Apresyan, B. Baldin, S. Banerjee, L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, G. Bolla, K. Burkett, J.N. Butler, A. Canepa, H.W.K. Cheung, F. Chlebana, J. Chramowicz, D. Christian, S. Cihangir${}^{\textrm{\textdagger}}$, M. Cremonesi, V.D. Elvira, I. Fisk, J. Freeman, C. Gingu, E. Gottschalk, L. Gray, D. Green, S. Grünendahl, O. Gutsche, D. Hare, R.M. Harris, S. Hasegawa, J. Hirschauer, J. Hoff, M. Hrycyk, Z. Hu, B. Jayatilaka, S. Jindariani, M. Johnson, U. Joshi, F. Kahlid, B. Klima, B. Kreis, S. Lammel, J. Linacre, D. Lincoln, R. Lipton, M. Liu, T. Liu, R. Lopes De Sá, J. Lykken, K. Maeshima, N. Magini, J.M. Marraffino, S. Maruyama, D. Mason, M. Matulik, P. McBride, P. Merkel, S. Mrenna, S. Nahn, V. O’Dell, K. Pedro, O. Prokofyev, G. Rakness, L. Ristori, E. Sexton-Kennedy, A. Shenai, A. Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N. Strobbe, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernieri, M. Verzocchi, R. Vidal, M. Wang, H.A. Weber, A. Whitbeck, Y. Wu, T. Zimmerman \cmsinstskip**University of Florida, Gainesville, USA

** D. Acosta, P. Avery, P. Bortignon, D. Bourilkov, A. Brinkerhoff, A. Carnes, M. Carver, D. Curry, S. Das, R.D. Field, I.K. Furic, J. Konigsberg, A. Korytov, J.F. Low, P. Ma, K. Matchev, H. Mei, G. Mitselmakher, D. Rank, L. Shchutska, D. Sperka, L. Thomas, J. Wang, S. Wang, J. Yelton \cmsinstskip**Florida International University, Miami, USA

** S. Linn, P. Markowitz, G. Martinez, J.L. Rodriguez \cmsinstskip**Florida State University, Tallahassee, USA

** A. Ackert, T. Adams, A. Askew, S. Bein, S. Hagopian, V. Hagopian, K.F. Johnson, H. Prosper, A. Santra, R. Yohay \cmsinstskip**Florida Institute of Technology, Melbourne, USA

** M.M. Baarmand, V. Bhopatkar, S. Colafranceschi, M. Hohlmann, D. Noonan, T. Roy, F. Yumiceva \cmsinstskip**University of Illinois at Chicago (UIC), Chicago, USA

** M.R. Adams, L. Apanasevich, D. Berry, R.R. Betts, I. Bucinskaite, R. Cavanaugh, L. Ennesser, A. Evdokimov, O. Evdokimov, L. Gauthier, C.E. Gerber, D.J. Hofman, K. Jung, S. Makauda, I.D. Sandoval Gonzalez, N. Varelas, H. Wang, Z. Wu, M. Zakaria, J. Zhang \cmsinstskip**The University of Iowa, Iowa City, USA

** B. Bilki\cmsAuthorMark69, W. Clarida, K. Dilsiz, S. Durgut, R.P. Gandrajula, M. Haytmyradov, V. Khristenko, J.-P. Merlo, H. Mermerkaya\cmsAuthorMark70, A. Mestvirishvili, A. Moeller, J. Nachtman, H. Ogul, Y. Onel, F. Ozok\cmsAuthorMark71, A. Penzo, C. Snyder, E. Tiras, J. Wetzel, K. Yi \cmsinstskip**Johns Hopkins University, Baltimore, USA

** I. Anderson, B. Blumenfeld, A. Cocoros, N. Eminizer, D. Fehling, L. Feng, A.V. Gritsan, P. Maksimovic, J. Roskes, U. Sarica, M. Swartz, M. Xiao, Y. Xin, C. You \cmsinstskip**The University of Kansas, Lawrence, USA

** A. Al-bataineh, P. Baringer, A. Bean, S. Boren, J. Bowen, J. Castle, L. Forthomme, R.P. Kenny III, S. Khalil, A. Kropivnitskaya, D. Majumder, W. Mcbrayer, M. Murray, S. Sanders, R. Stringer, J.D. Tapia Takaki, Q. Wang, G. Wilson \cmsinstskip**Kansas State University, Manhattan, USA

** A. Ivanov, K. Kaadze, Y. Maravin, A. Mohammadi, L.K. Saini, N. Skhirtladze, S. Toda \cmsinstskip**Lawrence Livermore National Laboratory, Livermore, USA

** F. Rebassoo, D. Wright \cmsinstskip**University of Maryland, College Park, USA

** C. Anelli, A. Baden, O. Baron, A. Belloni, B. Calvert, S.C. Eno, C. Ferraioli, J.A. Gomez, N.J. Hadley, S. Jabeen, G.Y. Jeng, R.G. Kellogg, T. Kolberg, J. Kunkle, A.C. Mignerey, F. Ricci-Tam, Y.H. Shin, A. Skuja, M.B. Tonjes, S.C. Tonwar \cmsinstskip**Massachusetts Institute of Technology, Cambridge, USA

** D. Abercrombie, B. Allen, A. Apyan, V. Azzolini, R. Barbieri, A. Baty, R. Bi, K. Bierwagen, S. Brandt, W. Busza, I.A. Cali, M. D’Alfonso, Z. Demiragli, L. Di Matteo, G. Gomez Ceballos, M. Goncharov, D. Hsu, Y. Iiyama, G.M. Innocenti, M. Klute, D. Kovalskyi, K. Krajczar, Y.S. Lai, Y.-J. Lee, A. Levin, P.D. Luckey, B. Maier, A.C. Marini, C. Mcginn, C. Mironov, S. Narayanan, X. Niu, C. Paus, C. Roland, G. Roland, J. Salfeld-Nebgen, G.S.F. Stephans, K. Tatar, M. Varma, D. Velicanu, J. Veverka, J. Wang, T.W. Wang, B. Wyslouch, M. Yang \cmsinstskip**University of Minnesota, Minneapolis, USA

** A.C. Benvenuti, R.M. Chatterjee, A. Evans, P. Hansen, S. Kalafut, S.C. Kao, Y. Kubota, Z. Lesko, J. Mans, S. Nourbakhsh, N. Ruckstuhl, R. Rusack, N. Tambe, J. Turkewitz \cmsinstskip**University of Mississippi, Oxford, USA

** J.G. Acosta, S. Oliveros \cmsinstskip**University of Nebraska-Lincoln, Lincoln, USA

** E. Avdeeva, K. Bloom, D.R. Claes, C. Fangmeier, R. Gonzalez Suarez, R. Kamalieddin, I. Kravchenko, A. Malta Rodrigues, J. Monroy, J.E. Siado, G.R. Snow, B. Stieger \cmsinstskip**State University of New York at Buffalo, Buffalo, USA

** M. Alyari, J. Dolen, A. Godshalk, C. Harrington, I. Iashvili, J. Kaisen, D. Nguyen, A. Parker, S. Rappoccio, B. Roozbahani \cmsinstskip**Northeastern University, Boston, USA

** G. Alverson, E. Barberis, A. Hortiangtham, A. Massironi, D.M. Morse, D. Nash, T. Orimoto, R. Teixeira De Lima, D. Trocino, R.-J. Wang, D. Wood \cmsinstskip**Northwestern University, Evanston, USA

** S. Bhattacharya, O. Charaf, K.A. Hahn, A. Kumar, N. Mucia, N. Odell, B. Pollack, M.H. Schmitt, K. Sung, M. Trovato, M. Velasco \cmsinstskip**University of Notre Dame, Notre Dame, USA

** N. Dev, M. Hildreth, K. Hurtado Anampa, C. Jessop, D.J. Karmgard, N. Kellams, K. Lannon, N. Marinelli, F. Meng, C. Mueller, Y. Musienko\cmsAuthorMark38, M. Planer, A. Reinsvold, R. Ruchti, N. Rupprecht, G. Smith, S. Taroni, M. Wayne, M. Wolf, A. Woodard \cmsinstskip**The Ohio State University, Columbus, USA

** J. Alimena, L. Antonelli, B. Bylsma, L.S. Durkin, S. Flowers, B. Francis, A. Hart, C. Hill, R. Hughes, W. Ji, B. Liu, W. Luo, D. Puigh, B.L. Winer, H.W. Wulsin \cmsinstskip**Princeton University, Princeton, USA

** S. Cooperstein, O. Driga, P. Elmer, J. Hardenbrook, P. Hebda, D. Lange, J. Luo, D. Marlow, T. Medvedeva, K. Mei, I. Ojalvo, J. Olsen, C. Palmer, P. Piroué, D. Stickland, A. Svyatkovskiy, C. Tully \cmsinstskip**University of Puerto Rico, Mayaguez, USA

** S. Malik \cmsinstskip**Purdue University, West Lafayette, USA

** A. Barker, V.E. Barnes, S. Folgueras, L. Gutay, N. Hinton, M.K. Jha, M. Jones, A.W. Jung, A. Khatiwada, D.H. Miller, N. Neumeister, J.F. Schulte, X. Shi, J. Sun, F. Wang, W. Xie \cmsinstskip**Purdue University Calumet, Hammond, USA

** N. Parashar, J. Stupak \cmsinstskip**Rice University, Houston, USA

** A. Adair, B. Akgun, Z. Chen, K.M. Ecklund, F.J.M. Geurts, M. Guilbaud, M. Kilpatrick, W. Li, B. Michlin, M. Northup, T. Nussbaum, B.P. Padley, J. Roberts, J. Rorie, Z. Tu, J. Zabel \cmsinstskip**University of Rochester, Rochester, USA

** B. Betchart, A. Bodek, P. de Barbaro, R. Demina, Y.t. Duh, T. Ferbel, M. Galanti, A. Garcia-Bellido, J. Han, O. Hindrichs, A. Khukhunaishvili, K.H. Lo, P. Tan, M. Verzetti \cmsinstskip**Rutgers, The State University of New Jersey, Piscataway, USA

** A. Agapitos, J.P. Chou, Y. Gershtein, T.A. Gómez Espinosa, E. Halkiadakis, M. Heindl, E. Hughes, S. Kaplan, R. Kunnawalkam Elayavalli, S. Kyriacou, A. Lath, K. Nash, M. Osherson, M. Park, H. Saka, S. Salur, S. Schnetzer, D. Sheffield, S. Somalwar, R. Stone, S. Thomas, P. Thomassen, M. Walker \cmsinstskip**University of Tennessee, Knoxville, USA

** A.G. Delannoy, M. Foerster, J. Heideman, G. Riley, K. Rose, S. Spanier, K. Thapa \cmsinstskip**Texas A&M University, College Station, USA

** O. Bouhali\cmsAuthorMark72, A. Celik, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R. Eusebi, J. Gilmore, T. Huang, E. Juska, T. Kamon\cmsAuthorMark73, R. Mueller, Y. Pakhotin, R. Patel, A. Perloff, L. Perniè, D. Rathjens, A. Safonov, A. Tatarinov, K.A. Ulmer \cmsinstskip**Texas Tech University, Lubbock, USA

** N. Akchurin, C. Cowden, J. Damgov, F. De Guio, C. Dragoiu, P.R. Dudero, J. Faulkner, E. Gurpinar, S. Kunori, K. Lamichhane, S.W. Lee, T. Libeiro, T. Peltola, S. Undleeb, I. Volobouev, Z. Wang \cmsinstskip**Vanderbilt University, Nashville, USA

** S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, P. Sheldon, S. Tuo, J. Velkovska, Q. Xu \cmsinstskip**University of Virginia, Charlottesville, USA

** M.W. Arenton, P. Barria, B. Cox, J. Goodell, R. Hirosky, A. Ledovskoy, H. Li, C. Neu, T. Sinthuprasith, X. Sun, Y. Wang, E. Wolfe, F. Xia \cmsinstskip**Wayne State University, Detroit, USA

** C. Clarke, R. Harr, P.E. Karchin, J. Sturdy \cmsinstskip**University of Wisconsin - Madison, Madison, WI, USA

** D.A. Belknap, J. Buchanan, C. Caillol, S. Dasu, L. Dodd, S. Duric, B. Gomber, M. Grothe, M. Herndon, A. Hervé, P. Klabbers, A. Lanaro, A. Levine, K. Long, R. Loveless, T. Perry, G.A. Pierro, G. Polese, T. Ruggles, A. Savin, N. Smith, W.H. Smith, D. Taylor, N. Woods \cmsinstskip†: Deceased

1:  Also at Vienna University of Technology, Vienna, Austria

2:  Also at State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China

3:  Also at Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS/IN2P3, Strasbourg, France

4:  Also at Universidade Estadual de Campinas, Campinas, Brazil

5:  Also at Universidade Federal de Pelotas, Pelotas, Brazil

6:  Also at Université Libre de Bruxelles, Bruxelles, Belgium

7:  Also at Deutsches Elektronen-Synchrotron, Hamburg, Germany

8:  Also at Joint Institute for Nuclear Research, Dubna, Russia

9:  Now at Cairo University, Cairo, Egypt

10: Also at Fayoum University, El-Fayoum, Egypt

11: Now at British University in Egypt, Cairo, Egypt

12: Now at Ain Shams University, Cairo, Egypt

13: Also at Université de Haute Alsace, Mulhouse, France

14: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia

15: Also at Tbilisi State University, Tbilisi, Georgia

16: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland

17: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany

18: Also at University of Hamburg, Hamburg, Germany

19: Also at Brandenburg University of Technology, Cottbus, Germany

20: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary

21: Also at MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös Loránd University, Budapest, Hungary

22: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary

23: Also at Indian Institute of Technology Bhubaneswar, Bhubaneswar, India

24: Also at University of Visva-Bharati, Santiniketan, India

25: Also at Indian Institute of Science Education and Research, Bhopal, India

26: Also at Institute of Physics, Bhubaneswar, India

27: Also at University of Ruhuna, Matara, Sri Lanka

28: Also at Isfahan University of Technology, Isfahan, Iran

29: Also at Yazd University, Yazd, Iran

30: Also at Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran

31: Also at Università degli Studi di Siena, Siena, Italy

32: Also at Laboratori Nazionali di Legnaro dell’INFN, Legnaro, Italy

33: Also at Purdue University, West Lafayette, USA

34: Also at International Islamic University of Malaysia, Kuala Lumpur, Malaysia

35: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia

36: Also at Consejo Nacional de Ciencia y Tecnología, Mexico city, Mexico

37: Also at Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

38: Also at Institute for Nuclear Research, Moscow, Russia

39: Now at National Research Nuclear University ’Moscow Engineering Physics Institute’ (MEPhI), Moscow, Russia

40: Also at St. Petersburg State Polytechnical University, St. Petersburg, Russia

41: Also at University of Florida, Gainesville, USA

42: Also at California Institute of Technology, Pasadena, USA

43: Also at INFN Sezione di Padova; Università di Padova; Università di Trento (Trento), Padova, Italy

44: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia

45: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia

46: Also at INFN Sezione di Roma; Università di Roma, Roma, Italy

47: Also at University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, Belgrade, Serbia

48: Also at Scuola Normale e Sezione dell’INFN, Pisa, Italy

49: Also at National and Kapodistrian University of Athens, Athens, Greece

50: Also at Riga Technical University, Riga, Latvia

51: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia

52: Also at Albert Einstein Center for Fundamental Physics, Bern, Switzerland

53: Also at Adiyaman University, Adiyaman, Turkey

54: Also at Istanbul Aydin University, Istanbul, Turkey

55: Also at Mersin University, Mersin, Turkey

56: Also at Cag University, Mersin, Turkey

57: Also at Piri Reis University, Istanbul, Turkey

58: Also at Ozyegin University, Istanbul, Turkey

59: Also at Izmir Institute of Technology, Izmir, Turkey

60: Also at Marmara University, Istanbul, Turkey

61: Also at Kafkas University, Kars, Turkey

62: Also at Istanbul Bilgi University, Istanbul, Turkey

63: Also at Yildiz Technical University, Istanbul, Turkey

64: Also at Hacettepe University, Ankara, Turkey

65: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom

66: Also at School of Physics and Astronomy, University of Southampton, Southampton, United Kingdom

67: Also at Instituto de Astrofísica de Canarias, La Laguna, Spain

68: Also at Utah Valley University, Orem, USA

69: Also at Argonne National Laboratory, Argonne, USA

70: Also at Erzincan University, Erzincan, Turkey

71: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey

72: Also at Texas A&M University at Qatar, Doha, Qatar

73: Also at Kyungpook National University, Daegu, Korea