Measurement of $y_{CP}$ in $D$ meson decays to CP eigenstates

TL;DR

This paper reports a measurement of the $y_{CP}$ parameter in $D^0$ meson decays to CP eigenstates, using a large data sample from the Belle detector, providing insights into charm meson mixing phenomena.

Contribution

First measurement of $y_{CP}$ in $D^0$ decays to $K_S^0K^+K^-$ using an untagged sample and Belle data, expanding understanding of charm mixing.

Findings

Measured $y_{CP} = (0.21 \, ext{±} \, 0.63 \, ext{(stat.)} \, ext{±} \, 0.78 \, ext{(syst.)} \, ext{±} \, 0.01 \, ext{(model))} ext{%}$.

Results consistent with no mixing within uncertainties.

Provides a new experimental constraint on charm mixing parameters.

Abstract

We present a measurement of the $D^0$-$\overline{D}^0$ mixing parameter $y_{CP}$ using a flavor-untagged sample of $D^0\to K_S^0K^+K^-$ decays. The measurement is based on a 673 fb$^{-1}$ data sample recorded by the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We find $y_{CP} = (0.21 \pm 0.63 ({\rm stat.})\pm 0.78 (\rm syst.) \pm 0.01(\rm model))%$.