Forward-backward asymmetries of lepton pairs in events with a large transverse momentum jet at hadron colliders

Abstract

We discuss forward-backward charge asymmetries for lepton pair production in association with a large transverse momentum jet at hadron colliders. The measurement of the lepton charge asymmetry relative to the jet direction A_{FB}^j gives a new determination of the effective weak mixing angle sin^2{\theta_{eff}^{lept}(M_Z^2)} with in principle a statistical precision after cuts of \sim 10^{-3} (8 x 10^{-3}) at LHC (Tevatron), due to the large cross section of the process with initial gluons. The identification of b jets also allows for the measurement of the bottom quark Z asymmetry A_{FB}^b at hadron colliders although with a lower precision than at LEP, the resulting statistical precision for sin^2{\theta_{eff}^{lept}(M_Z^2)} being \sim 9 x 10^{-4} (2 x 10^{-2} at Tevatron).