Heavy-light decay topologies as a new strategy to discover a heavy gluon

TL;DR

This paper explores a new collider signature involving heavy-light decays of a Kaluza-Klein gluon in warped extra dimension theories, showing these channels are promising for discovering heavy gluons and heavy fermions at the LHC.

Contribution

It introduces the significance of heavy-light decay channels of the KK gluon, overlooked before, and analyzes their potential for discovery at the LHC using a simplified two-site model.

Findings

LHC can discover KK gluons with masses 1.8-2.2 TeV at 7 TeV with 10 fb^{-1}.

Heavy-light decay channels are powerful for heavy gluon detection.

Potential to discover heavy fermion partners with relatively low luminosity.

Abstract

We study the collider phenomenology of the lightest Kaluza-Klein excitation of the gluon, G*, in theories with a warped extra dimension. We do so by means of a two-site effective lagrangian which includes only the lowest-lying spin-1 and spin-1/2 resonances. We point out the importance of the decays of G* to one SM plus one heavy fermion, that were overlooked in the previous literature. It turns out that, when kinematically allowed, such heavy-light decays are powerful channels for discovering the G*. In particular, we present a parton-level Montecarlo analysis of the final state Wtb that follows from the decay of G* to one SM top or bottom quark plus its heavy partner. We find that at \sqrt{s} = 7 TeV and with 10 fb^{-1} of integrated luminosity, the LHC can discover a KK gluon with mass in the range M_{G*} = (1.8 - 2.2) TeV if its coupling to a pair of light quarks is g_{G*qqbar} = (0.2-0.5) g_3. The same process is also competitive for the discovery of the top and bottom partners as well. We find, for example, that the LHC at \sqrt{s} = 7 TeV can discover a 1 TeV KK bottom quark with an integrated luminosity of (5.3 - 0.61) fb^{-1} for g_{G*qqbar} = (0.2-0.5) g_3.