Measurement of Charmed Meson Lifetimes with Belle

TL;DR

This paper reports precise measurements of charmed meson lifetimes and the mixing parameter y_{CP} using Belle detector data, providing important insights into charm quark behavior and CP violation.

Contribution

First measurement of charmed meson lifetimes and y_{CP} parameter using Belle data with full reconstruction and flavor identification.

Findings

Measured lifetimes: D^0=414.8 fs, D^+=1040 fs, D_s^+=479 fs.

Y_{CP} measured as (1.0^{+3.8}_{-3.5}{}^{+1.1}_{-2.1})%.

Y_{CP} 95% confidence interval: -7.0% to 8.7%.

Abstract

The lifetimes of charmed mesons have been measured using 2.75fb$^{-1}$ 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 $\tau(D^0)=(414.8\pm3.8\pm3.4)$ fs, $\tau(D^+)=(1040^{+23}_{-22}\pm18)$ fs and $\tau(D_s^+)=(479^{+17}_{-16}{}^{+6}_{-8})$ fs, where the first error is statistical and the second error is systematic. The mixing parameter $y_{CP}$ is also measured through the lifetime difference of $D^0$ mesons decaying into CP-mixed states and CP eigenstates. We find $y_{CP}=(1.0^{+3.8}_{-3.5}{}^{+1.1}_{-2.1})%$, corresponding to a 95% confidence interval $-7.0%<\ycp<8.7%$.