Golden mode for a baryonicZ′boson at hadronic colliders:pp/pp¯→WZ′→ℓνbb¯

Abstract

Associated production of a baryonic ${Z}^{\ensuremath{'}}$ 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 ${Z}^{\ensuremath{'}}$ at the Tevatron and at the LHC, including $\ensuremath{\gamma}{Z}^{\ensuremath{'}}$ and $Z{Z}^{\ensuremath{'}}$ with ${Z}^{\ensuremath{'}}\ensuremath{\rightarrow}jj$. We show that the chances of confirming this baryonic ${Z}^{\ensuremath{'}}$ are 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 the $\ensuremath{\gamma}{Z}^{\ensuremath{'}}$ and $Z{Z}^{\ensuremath{'}}$ channels at the Tevatron and also at the LHC. Nevertheless, the search using the $b\overline{b}$ decay mode of ${Z}^{\ensuremath{'}}$ is much more feasible at the LHC, provided that the branching ratio $B({Z}^{\ensuremath{'}}\ensuremath{\rightarrow}b\overline{b})>0.1$. In particular, the $W{Z}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\ell}\ensuremath{\nu}b\overline{b}$ mode has a signal-to-background ratio larger than 1. Even with $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ luminosity at the LHC, it can lead to a high significance level. The $W{Z}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\ell}\ensuremath{\nu}b\overline{b}$ and $\ensuremath{\gamma}{Z}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}b\overline{b}$ are also highly observable at the Tevatron.