Lepton asymmetries in heavy baryon decays of Λb→Λl+l−

Abstract

We study the dilepton forward–backward and the longitudinal, normal and transverse lepton polarization asymmetries in the heavy baryon decays of Λb→Λl+l−. We show that the asymmetries have a less dependence on the nonperturbative QCD effects. In the standard model, we find that the integrated forward–backward asymmetries (FBAs) and three components of the polarizations in the QCD sum rule approach (pole model) are −0.13(−0.12) and (58.3,−9.4,−0.07)% ((58.3,−12.6,−0.07)%) for Λb→Λμ+μ− and −0.04(−0.03) and (10.9,−10.0,−0.39)% ((10.9,−0.2,−0.34)%) for Λb→Λτ+τ−, respectively.