Search for High-Mass Diphoton Resonances in pp Collisions at sqrt(s)=8 TeV with the CMS Detector

A search for high-mass diphoton resonances is performed in proton-proton collisions at $\sqrt{s}=8$~TeV, with data corresponding to an integrated luminosity of 19.5~fb$^{-1}$, collected by the CMS detector at the CERN Large Hadron Collider. Such a diphoton resonance could be a signature of an excited state of the graviton in the Randall-Sundrum scenario with a warped extra dimension of space. The background to this signal comes from real standard model diphoton production, and from photon+jet or dijet processes where one or two jets produce a fake photon signature in the detector. The observed diphoton mass distribution is compared to the background prediction, and no significant excess of events over the background is found. 95\% confidence level limits are set in the parameter space of the Randall-Sundrum model: masses below $1450-2780$~GeV are excluded for the first excited state of the Randall-Sundrum graviton, for values of the coupling parameter $k/M_{\textrm{Pl}}$ in the range $0.01 \le k/M_{\textrm{Pl}} \le 0.1$.