The Golden Mode for a Baryonic $Z'$ Boson at Hadronic Colliders: pp/ppbar -> WZ' -> l nu b b-bar

Abstract

Associated production of a baryonic Z' boson with the W boson can account for the excess in Wjj production observed by the CDF collaboration at the Tevatron. We analyze other possible channels of this Z' at the Tevatron and at the LHC, including \gamma Z' and Z Z' with the Z' -> jj. We show that the chances of confirming this baryonic Z' is better at the Tevatron than at the LHC because of the faster growing backgrounds at the LHC. Unfortunately the current systematic uncertainties of the order of 10% cannot yield any significant excess in both \gamma Z' and Z Z' channels at the Tevatron and also at the LHC. Nevertheless the search using the b\bar b decay mode of Z' is much more feasible at the LHC, provided that the branching ratio B(Z' -> b\bar b) > 0.1. In particular, the W Z' -> l \nu b\bar b mode has a signal-to-background ratio larger than 1. Even with 1 fb^{-1} luminosity at the LHC it can lead to a high significance level. The WZ' -> l \nu b \bar b and \gamma Z' -> \gamma b \bar b are also highly observable at the Tevatron.