Performance of algorithms that reconstruct missing transverse momentum in $\sqrt{s}=$ 8 TeV proton-proton collisions in the ATLAS detector

TL;DR

This paper evaluates the performance of missing transverse momentum reconstruction algorithms in the ATLAS detector at 8 TeV, focusing on pileup suppression and comparing data with simulation for various event types.

Contribution

It presents a detailed assessment of $E_{T}^{miss}$ reconstruction algorithms' performance and systematic uncertainties using 8 TeV collision data, highlighting improvements in pileup mitigation.

Findings

Reconstruction algorithms effectively suppress pileup effects.

Good agreement between data and simulation for $E_{T}^{miss}$.

Quantified systematic uncertainties in $E_{T}^{miss}$ measurements.

Abstract

The reconstruction and calibration algorithms used to calculate missing transverse momentum ($E_{\rm T}^{\rm miss}$) with the ATLAS detector exploit energy deposits in the calorimeter and tracks reconstructed in the inner detector as well as the muon spectrometer. Various strategies are used to suppress effects arising from additional proton-proton interactions, called pileup, concurrent with the hard-scatter processes. Tracking information is used to distinguish contributions from the pileup interactions using their vertex separation along the beam axis. The performance of the $E_{\rm T}^{\rm miss}$ reconstruction algorithms, especially with respect to the amount of pileup, is evaluated using data collected in proton-proton collisions at a centre-of-mass energy of 8 TeV during 2012, and results are shown for a data sample corresponding to an integrated luminosity of 20.3 fb$^{-1}$. The results of simulation modelling of $E_{\rm T}^{\rm miss}$ in events containing a $Z$ boson decaying to two charged leptons (electrons or muons) or a $W$ boson decaying to a charged lepton and a neutrino is compared to data. The acceptance for different event topologies, with and without high transverse momentum neutrinos, is shown for a range of threshold criteria for $E_{\rm T}^{\rm miss}$, and estimates of the systematic uncertainties in the $E_{\rm T}^{\rm miss}$ measurements are presented.