Search for dark matter and unparticles produced in association with a Z boson in proton-proton collisions at root s=8 TeV


Khachatryan V., Sirunyan A. M. , Tumasyan A., Adam W., Asilar E., Bergauer T., ...More

PHYSICAL REVIEW D, vol.93, no.5, 2016 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 93 Issue: 5
  • Publication Date: 2016
  • Doi Number: 10.1103/physrevd.93.052011
  • Title of Journal : PHYSICAL REVIEW D

Abstract

A search for evidence of particle dark matter (DM) and unparticle production at the LHC has been performed using events containing two charged leptons, consistent with the decay of a Z boson, and large missing transverse momentum. This study is based on data collected with the CMS detector corresponding to an integrated luminosity of 19.7 fb(-1) of pp collisions at the LHC at a center-of-mass energy of 8 TeV. No significant excess of events is observed above the number expected from the standard model contributions. The results are interpreted in terms of 90% confidence level limits on the DM-nucleon scattering cross section, as a function of the DM particle mass, for both spin-dependent and spin-independent scenarios. Limits are set on the effective cutoff scale., and on the annihilation rate for DM particles, assuming that their branching fraction to quarks is 100%. Additionally, the most stringent 95% confidence level limits to date on the unparticle model parameters are obtained.