Reem Rasheed ; Jerome Baudot ; Giulio Dujany ; Sviatoslav Bilokin ; Isabelle-Ripp Baudot

15 May 2020

Abstract: This document presents the measurement of B 0 meson lifetimes using the 2019 Belle II dataset that corresponds to an integrated luminosity of $8.7 \pm 0.2 fb^{-1}$. Each candidate is fully reconstructed with hadronic decay final states on the signal side, while the rest-of-event technique allows to infer the decay vertex position on the other (tag) side. $B^{0}$ lifetime is extracted from an unbinned maximum likelihood fit to the distribution of the difference between the signal side $B^{0}$ candidate and the tag side decay times. The measured lifetime is $\tau_{B^{0}} = 1.48 \pm 0.28 \pm 0.06$ ps, where the first uncertainty is statistical and the second is systematic.

Keyword(s): B^{0} lifetime, ; Belle II ; hadronic decays