Measurement of the B-0 lifetime and flavor-oscillation frequency using hadronic decays reconstructed in 2019-2021 Belle II data

Abstract

We measure the B-0 lifetime and flavor-oscillation frequency using B-0 -> D(*)-x+ decays collected by the Belle II experiment in asymmetric-energy e+e- collisions produced by the SuperKEKB collider operating at the T(4S) resonance. We fit the decay-time distribution of signal decays, where the initial flavor is determined by identifying the flavor of the other B meson in the event. The results, based on 33000 signal decays reconstructed in a data sample corresponding to 190 fb(-1), are zB(0) = (1.499 +/- 0.013 +/- 0.008) ps, Amd = (0.516 +/- 0.008 +/- 0.005) ps(-1), where the first uncertainties are statistical and the second are systematic. These results are consistent with the world-average values.