Search for Dark Matter and Large Extra Dimensions in pp Collisions Yielding a Photon and Missing Transverse Energy

TL;DR

This study searches for signs of dark matter particles and large extra dimensions in proton-proton collisions producing a photon and missing energy, setting new limits on these phenomena based on CMS data.

Contribution

It provides the most sensitive upper limits to date on dark matter production and large extra dimensions using photon plus missing energy events at 7 TeV.

Findings

No excess over standard model expectations observed.

Sets new upper limits on dark matter particle production cross sections.

Excludes certain models of large extra dimensions with Planck scales between 1.65 and 1.71 TeV.

Abstract

Results are presented from a search for new physics in the final state containing a photon and missing transverse energy. The data correspond to an integrated luminosity of 5.0 inverse femtobarns collected in pp collisions at sqrt(s) = 7 TeV by the CMS experiment. The observed event yield agrees with standard-model expectations for the photon-plus-missing-transverse-energy events. Using models for production of dark-matter particles (chi), we set 90% confidence level (C.L.) upper limits of 13.6--15.4 femtobarns on chi production in the photon-plus-missing-transverse-energy state. These provide the most sensitive upper limits for spin-dependent chi-nucleon scattering for chi masses between 1 and 100 GeV. For spin-independent contributions, the present limits are extended to chi masses below 3.5 GeV. For models with 3--6 large extra dimensions, our data exclude extra-dimensional Planck scales between 1.65 and 1.71 TeV at 95% C.L.