Direct CP Violation in Charm Decays due to Left-Right Mixing

TL;DR

This paper explores how left-right mixing in a general LR symmetric model can explain the observed CP asymmetry difference in charm decays, aligning with recent experimental deviations while satisfying existing constraints.

Contribution

It demonstrates that the large CP asymmetry difference in charm decays can be explained by non-manifest LR mixing without conflicting with other flavor constraints.

Findings

LR mixing can account for the observed CP asymmetry difference

Constraints from kaon and D-meson mixing are satisfied

The model provides a viable new physics explanation for recent experimental results

Abstract

Motivated by the $3.8\sigma$ deviation from no CP violation hypothesis for the CP asymmetry (CPA) difference between $D^0\to K^+ K^-$ and $D^0\to \pi^+ \pi^-$, reported recently by LHCb and CDF, we investigate the CP violating effect due to the left-right (LR) mixing in the general LR symmetric model. In particular, in the non-manifest LR model we show that the large CPA difference could be explained, while the constraints from $(\epsilon'/\epsilon)_K$ and $D^0$-$\bar D^0$ are satisfied.