CP violation in hadronic tau decays

TL;DR

This paper investigates CP violation effects in specific tau decays involving multiple pions and kaons, exploring potential signals of physics beyond the Standard Model through interference with charged Higgs contributions.

Contribution

It analyzes CP-odd observables in tau decays, focusing on asymmetries that could reveal new physics beyond the Standard Model.

Findings

Partial rate asymmetries are expected to be small.

Other asymmetries could be measurable.

Interference with charged Higgs can induce observable CP violation.

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.