CMS-PAS-EXO-12-054

CMS-PAS-EXO-12-054
Search for dark matter and unparticles produced in association with a Z boson in pp collisions at $\sqrt{s} =$ 8 TeV
CMS Collaboration
July 2015

Abstract: Events containing two oppositely charged same-flavor leptons and large missing transverse energy are investigated to probe for evidence of dark matter (DM) or unparticle production at the Large Hadron Collider (LHC). This study is based on the data collected by 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. In the selected signal region, the observed data are consistent with the expected standard model backgrounds; no excess of events is observed. 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 also set on the DM annihilation rate assuming 100% branching fraction of DM annihilating to quarks and on the effective coupling cut-off scale $\Lambda$. Finally, the most stringent limits on the unparticle model parameters $\lambda$ and $\Lambda_{\mathcal U}$ are obtained.
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; These preliminary results are superseded in this paper, PRD 93 (2016) 052011. The superseded preliminary plots can be found here.

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