Direct CP violation in $\tau^\pm\rightarrow K^\pm \rho^0 (\omega)\nu_\tau \rightarrow K^\pm \pi^+\pi^-\nu_\tau $

TL;DR

This paper investigates direct CP violation in tau decays involving rho and omega mesons within the Standard Model, highlighting a mechanism that could amplify CP asymmetries and leave room for new physics discoveries.

Contribution

It introduces a charge symmetry violating mixing mechanism between rho and omega mesons to enhance CP asymmetry in tau decay processes.

Findings

Maximum differential CP asymmetry: approximately -5.6×10^{-12}

Localized integrated CP asymmetry: approximately 6.3×10^{-11}

Room for new physics beyond the Standard Model.

Abstract

We study the direct CP violation in the $\tau^\pm\rightarrow K^\pm \rho^0 (\omega)\nu_\tau \rightarrow K^\pm \pi^+\pi^-\nu_\tau$ decay process in the Standard Model. An interesting mechanism involving the charge symmetry violating mixing between $\rho^0$ and $\omega$ is applied to enlarge the CP asymmetry. With this mechanism, the maximum differential and localized integrated CP asymmetries can reach $-(5.6^{+2.9}_{-1.7})\times10^{-12}$ and $6.3^{+2.4}_{-3.3}\times 10^{-11}$, respectively, which still leave plenty room for CP-violating New Physics to be discovered through this process.