Search for dark matter, extra dimensions, and unparticles in monojet events in proton-proton collisions at sqrt(s) = 8 TeV

TL;DR

This paper reports a search for dark matter, extra dimensions, and unparticles in monojet events at 8 TeV proton-proton collisions, finding no deviation from the standard model and setting new limits on various theoretical models.

Contribution

It provides the most stringent collider limits on ADD extra dimensions, unparticles, and DM-nucleon cross sections to date.

Findings

No excess events observed beyond standard model predictions.

Set new upper limits on DM-nucleon scattering cross sections.

Established the most stringent constraints on ADD and unparticle models.

Abstract

Results are presented from a search for particle dark matter (DM), extra dimensions, and unparticles using events containing a jet and an imbalance in transverse momentum. The data were collected by the CMS detector in proton-proton collisions at the LHC and correspond to an integrated luminosity of 19.7 inverse femtobarns at a centre-of-mass energy of 8 TeV. The number of observed events is found to be consistent with the standard model prediction. Limits are placed on the DM-nucleon scattering cross section as a function of the DM particle mass for spin-dependent and spin-independent interactions. Limits are also placed on the scale parameter M[D] in the ADD model of large extra dimensions, and on the unparticle model parameter Lambda[U]. The constraints on ADD models and unparticles are the most stringent limits in this channel and those on the DM-nucleon scattering cross section are an improvement over previous collider results.