CP violation in hadronic tau decays

Abstract

We consider CP-violating effects in tau -> 3 pi nu_ tau and 4 pi nu_ tau (Delta S = 0), and tau -> K pi pi nu_tau (Delta S = 1), assuming that the usual Standard Model amplitudes for these processes interfere with analogous amplitudes mediated by a charged Higgs boson. In the Delta S = 0 case we focus specifically on the intermediate resonant processes tau -> V pi nu_tau (with V=omega, rho, and a_1), and consider three CP-odd observables -- the partial rate asymmetry, a polarization-dependent asymmetry and a triple-product asymmetry. In the Delta S = 1 case we examine the partial rate asymmetry, two "modified" rate asymmetries, and a triple-product asymmetry. The partial rate asymmetry is expected to be small for both the Delta S = 0 and Delta S = 1 cases. Evaluation of the other asymmetries indicates that they could potentially be measurable.