# Implication of the D^0 Width Difference On CP-Violation in D^0-\bar D^0 Mixing

## TL;DR

This paper discusses how the observed width difference in the D0-D0bar system constrains CP-violation, suggesting that a significant CP-violating phase would indicate new physics beyond the Standard Model.

## Contribution

It demonstrates that current measurements of the width difference impose constraints on the CP-violating phase in D0-D0bar mixing, highlighting potential signals of new physics.

## Key findings

- Measured width difference constrains CP-violating phase
- Significant CP-violation would indicate new physics
- Current data limits possible CP-violation in D mixing

## Abstract

Both BaBar and Belle have found evidence for a non-zero width difference in the $D^0$-$\bar D^0$ system. Although there is no direct experimental evidence for CP-violation in $D$ mixing (yet), we show that the measured values of the width difference $y\sim \Delta\Gamma$ already imply constraints on the CP-violating phase in $D$ mixing, which, if significantly different from zero, would be an unambiguous signal of new physics.