On the possibility of light string resonances at the LHC and Tevatron from Randall-Sundrum throats

Abstract

In string realizations of the Randall-Sundrum scenario, the higher-spin Regge excitations of Standard Model states localized near the IR brane are warped down to close to the TeV scale. We argue that, as a consequence of the localization properties of Randall-Sundrum models of flavour, the lightest such resonance is the spin-3/2 excitation, tR*, of the right-handed top quark over a significant region of parameter space. A mild accidental cancellation allows the tR* to be as light or lighter than the Kaluza-Klein excitations of the Standard Model states. We consider from a bottom-up effective theory point of view the production and possible observability of such a spin-3/2 excitation at the LHC and Tevatron. Current limits are weaker than might be expected because of the excess of WWjj events at the Tevatron reported by CDF at Minv ≃ 400−500 GeV.