CP Violation in $\tau$ Decays at SuperB \& Super-Belle Experiments -- like Finding Signs of Dark Matter

TL;DR

This paper discusses the potential for future SuperB and Belle II experiments to detect new physics through CP violation measurements in tau decays, building on BaBar's findings and exploring correlations with other particles.

Contribution

It proposes a comprehensive approach to identify new dynamics in CP asymmetries in tau decays and emphasizes the importance of correlations with other final states and experiments.

Findings

BaBar observed a 2.8 sigma deviation in CP asymmetry from SM prediction.

Future experiments can probe more decay channels for CP violation.

Correlations between different final states can help identify new physics.

Abstract

BaBar has found $A_{\rm CP}(\tau^- \to \nu K_S\pi^- [\geq \pi^0]) = (-0.36 \pm 0.23 \pm 0.11)%$ with 2.8 $\sigma$ difference with SM prediction $A_{\rm CP}(\tau^- \to \nu K_S\pi^-) = (0.36 \pm 0.01)%$ based on $K^0 - \bar K^0$ oscillation. Four central points: (i) to establish both the `existence' of New Dynamics (ND) and its `features' in local CP asymmetries; (ii) to increase the number of final states to be probed; (iii) to emphasize correlations of CP violations between different final states; (iv) likewise for the correlations with $D^{\pm}$ final states. These measurements should be possible at SuperB & Belle II experiments.