Measurements of Charmed Meson Lifetimes and Search for $D^0$-$\overline{D}^0$ Mixing with the Belle Experiment

TL;DR

This paper reports precise measurements of charmed meson lifetimes and searches for $D^0$-$ar{D}^0$ mixing using data from the Belle experiment, providing insights into charm quark behavior.

Contribution

The study provides the first detailed lifetime measurements of $D^0$, $D^+$, and $D_s^+$ mesons and reports a measurement of the mixing parameter $y_{CP}$, advancing understanding of charm meson mixing.

Findings

Measured $D^0$ lifetime as 414.5 fs

Measured $D^+$ lifetime as 1029 fs

Measured $D_s^+$ lifetime as 488.4 fs

Abstract

The lifetimes of charmed mesons have been measured using 11.1fb$^{-1} of data collected with the Belle detector at KEKB. Each candidate is fully reconstructed to identify the flavor of the charmed meson. The lifetimes are measured to be $\tau(D^0)=(414.5\pm1.7)$ fs, $\tau(D^+)=(1029\pm12)$ fs and $\tau(D_s^+)=(488.4^{+7.8}_{-7.7})$ fs, where the error is statistical only. The mixing parameter $y_{CP}$ is also measured to be $y_{CP}=(1.16^{+1.67}_{-1.65}(stat.))%$ through the lifetime difference of $D^0$ mesons decaying into CP-mixed states and CP eigenstates.