Precise measurement of the $D^0$ and $D^+$ lifetimes at Belle II

TL;DR

This paper reports the most precise measurements to date of the $D^0$ and $D^+$ meson lifetimes using Belle II data, confirming previous results with improved accuracy.

Contribution

First precise measurement of $D^0$ and $D^+$ lifetimes at Belle II, utilizing 72 fb$^{-1}$ of data and advanced reconstruction techniques.

Findings

$D^0$ lifetime measured as 410.5 fs

$D^+$ lifetime measured as 1030.4 fs

Results are consistent with previous measurements

Abstract

We report a measurement of the $D^0$ and $D^+$ lifetimes using $D^0\to K^-\pi^+$ and $D^+\to K^-\pi^+\pi^+$ decays reconstructed in $e^+e^-\to c\bar{c}$ data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy $e^+e^-$ collider. The data, collected at center-of-mass energies at or near the $\Upsilon(4S)$ resonance, correspond to an integrated luminosity of $72\,{\rm fb}^{-1}$. The results, $\tau(D^0) = 410.5\pm1.1\,{\rm(stat)}\pm0.8\,{\rm(syst.)}\,{\rm fs}$ and $\tau(D^+) = 1030.4\pm4.7\,{\rm(stat)}\pm3.1\,{\rm(syst.)}\,{\rm fs}$, are the most precise to date and are consistent with previous determinations.