Search for signatures of extra dimensions in the diphoton mass spectrum at the Large Hadron Collider

TL;DR

This study searches for signs of extra spatial dimensions in diphoton mass spectra at the LHC, finding no excess but setting the most restrictive bounds to date on models involving extra dimensions and graviton excitations.

Contribution

It provides new, more stringent experimental limits on the parameters of extra-dimensional models using CMS data at 7 TeV.

Findings

No excess observed above standard model expectations.

Set lower limits on the effective Planck scale (2.3-3.8 TeV).

Set lower limits on graviton mass (0.86-1.84 TeV).

Abstract

A search for signatures of extra dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at sqrt(s) = 7 TeV corresponding to an integrated luminosity of 2.2 inverse femtobarns. In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.