Kaluza-Klein gluons as a diagnostic of warped models

We study the properties of g¹, the first excited state of the gluon in representative variants of the Randall-Sundrum (RS) model with the standard model (SM) fields in the bulk. We find that measurements of the coupling to light quarks (from the inclusive cross section for pp→g¹→tt̄), the coupling to bottom quarks (from the rate of pp→g¹b), as well as the overall width can provide powerful discriminants between the models. In models with large brane kinetic terms, the g¹ resonance can even potentially be discovered decaying into dijets against the large QCD background. We also derive bounds based on existing Tevatron searches for resonant tt̄ production and find that they require M_g¹950 GeV. In addition, we explore the pattern of interference between the g¹ signal and the nonresonant SM background, defining an asymmetry parameter for the invariant mass distribution. The interference probes the relative signs of the couplings of the g¹ to light quark pairs and to tt̄, and thus provides an indication that the top is localized on the other side of the extra dimension from the light quarks, as is typical in the RS framework.