On the spin and parity of a single-produced resonance at the LHC

Abstract

Both LHC experiments, ATLAS and CMS, observed a new narrow resonance near 125 GeV.We demonstrate that the spin, parity, and, more generally, the tensor structure of the boson couplings of this resonance can be obtained by studying mass and angular distributions of events where the resonance decays to pairs of gauge bosons, ZZ, WW and γγ To account for all spin correlations we calculate kinematic distributions analytically and develop a Monte Carlo generator. We also discuss how to use angular and mass distributions of the resonance decay products for optimal background rejection and for distinguishing different signal hypotheses. By the end of the 8 TeV run of the LHC, it might be possible to separate extreme hypotheses of the spin and parity of the new resonance with a confidence level of 99% or better for a wide range of models.