Implications on the first observation of charm CPV at LHCb

TL;DR

The paper discusses the first observation of CP violation in charm decays by LHCb, compares it with Standard Model predictions, and suggests further measurements to explore CPV effects.

Contribution

It validates the FAT approach's prediction of charm CPV and proposes new decay modes for future experimental investigation.

Findings

LHCb observed charm CPV at about -1.54×10^{-3}

FAT approach predicted CPV in the same range

Proposed measurement of D+→K+K−π+ decay

Abstract

Very recently, the LHCb Collaboration observed the $CP$ violation (CPV) in the charm sector for the first time, with $\Delta A_{CP}^{\rm dir}\equiv A_{CP}(D^0\to K^+K^-)-A_{CP}(D^0\to \pi^+\pi^-)=(-1.54\pm0.29)\times10^{-3}$. This result is consistent with our prediction of $\Delta A_{CP}^{\rm SM}=(-0.57\sim -1.87)\times 10^{-3}$ obtained in the factorization-assisted topological-amplitude (FAT) approach in [PRD86,036012(2012)]. It implies that the current understanding of the penguin dynamics in charm decays in the Standard Model is reasonable. Motivated by the success of the FAT approach, we further suggest to measure the $D^+\to K^+K^-\pi^+$ decay, which is the next potential mode to reveal the CPV of the same order as $10^{-3}$.