CP violation in B0_d --> tau+ tau- decays

Abstract

Establishing CP violation in B0 (bar{B0}) --> l+ l- decays requires a measurement of polarization of the final lepton pair, or a precise determination of the B0 --> l+ l- and bar{B0} --> l+ l- rates. We first argue that if the amplitudes of these decays are dominated by the scalar and pseudoscalar Higgs penguin diagrams, as happens e.g. in supersymmetry with large tan(beta), the CP asymmetries depend practically on only one CP violating phase. This phase can be large, of the order of the CKM phase, leading to large CP asymmetries in the tau+ tau- decay channel of B0_d (bar{B0}_d) mesons, potentially measurable in BELLE or BABAR experiments. Secondly, we show that the existing TAUOLA tau-lepton decay library supplemented by its universal interface can efficiently be used to search for B0 (bar{B0}) --> tau+ tau- decays, and to investigate how the CP asymmetry is reflected in realistic experimental observables.