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

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.

Figures (3)

• Figure 1: The photon $p_{\mathrm{T}}$ distribution for the candidate sample, compared with estimated contributions from SM backgrounds and a prediction from ADD for $M_{D}=1\,\text{Te\spaceV}\xspace$ and $n$ = 3.
• Figure 2: The 90% CL upper limits on the $\chi$-nucleon cross section as a function of $M_{\chi}$ for (a) spin-independent and (b) spin-dependent scattering. Also shown are the limits from selected experiments with published XENON100CDMS1CDMS2COGENTSIMPLE1COUPPIceCubeSUPERK and preliminary CDFdm results.
• Figure 3: (a) The 95% CL upper limits on the LO and NLO ADD cross sections as a function of $M_{D}$ for $n$ = 4 and 6. (b) Limits on $M_{D}$ as a function of $n$, compared to LO results from similar searches at the Tevatron CDFgammaD0gamma and LEP LEPgamma.