Tau lepton charge asymmetry and new physics at the LHC

We consider the possibility of studying new physics that singles out the tau lepton at the LHC. We concentrate on the tau lepton charge asymmetry in ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ pair production as a tool to probe this physics beyond the standard model. We consider two generic scenarios for the new physics. We first study a nonuniversal ${Z}^{\ensuremath{'}}$ boson as an example of a new resonance that can single out tau leptons. We then consider vector lepto-quarks coupling the first-generation quarks with the third-generation leptons as an example of nonresonant new physics. We find that in both cases the charge asymmetry can be sufficiently sensitive to the new physics to provide useful constraints at the LHC.