Direct CP Violation in Nonleptonic Charm Decays

TL;DR

This paper analyzes recent experimental evidence of direct CP violation in charm decays, constrains standard model penguin contributions, and predicts effects on other decay channels.

Contribution

It provides a QCD-enhanced standard model analysis of CP violation in charm decays and predicts asymmetries in additional decay modes.

Findings

Measured $ riangle A_{CP}$ constrains penguin amplitudes.

Predicted CP asymmetries in $D^0 o\pi^0\pi^0$ and $D^+ o K^+ar{K}^0$.

Supports standard model explanations for observed CP violation.

Abstract

LHCb, CDF and most recently Belle have observed a large difference between direct CP asymmetries in $D^0\to K^+K^-$ and $D^0\to\pi^+\pi^-$. We use the measured value of $\Delta A_{CP}$ to constrain the magnitude and strong phase of a QCD-enhanced standard model penguin and predict its effects on direct CP asymmetry in $D^0\to\pi^0\pi^0$ and $D^+\to K^+\bar{K}^0$.