Spin identification of the Randall-Sundrum resonance in lepton-pair production at the CERN LHC

Abstract

The determination of the spin of the quantum states exchanged in the various nonstandard interactions is a relevant aspect in the identification of the corresponding scenarios. We discuss the identification reach at the CERN LHC on the spin-2 of the lowest-lying Randall-Sundrum (RS) resonance, predicted by gravity with one warped extra dimension, against spin-1 and spin-0 nonstandard exchanges with the same mass and producing the same number of events in the cross section. We focus on the angular distributions of leptons produced in the Drell-Yan process at the LHC; in particular, we use as a basic observable a 'normalized' integrated angular asymmetry A{sub CE}. Our finding is that the 95% C.L. identification reach on the spin-2 of the RS resonance (equivalently, the exclusion reach on both the spin-1 and spin-0 hypotheses for the peak) is up to a resonance mass scale of the order of 1.0 or 1.6 TeV in the case of weak coupling between graviton excitations and SM particles (k/M{sub Pl}=0.01) and 2.4 or 3.2 TeV for a larger coupling constant (k/M{sub Pl}=0.1) for a time-integrated LHC luminosity of 10 or 100 fb{sup -1}, respectively. Also, some comments are given on the complementary roles of the angular analysismore » and the eventual discovery of the predicted second graviton excitation in the identification of the RS scenario.« less