R. Tiwary ; R. Mehta ; R. Dhamija ; S Sandilya ; G. B. Mohanty

10 October 2021

Abstract: This paper reports a study of B→K∗γ decays using 62.8±0.6 fb−1 of data collected during 2019–2020 by the Belle II experiment at the SuperKEKB e+e− asymmetric-energy collider, corresponding to (68.2±0.8)×10^6 BB events. We find 454±28, 50±10, 169±18, and 160±17 signal events in the decay modes B0→K∗0[K+π−]γ, B0→K∗0[K0Sπ0]γ, B+→K∗+[K+π0]γ, and B+→K∗+[K+π0]γ, respectively. The uncertainties quoted for the signal yield are statistical only. We report the branching fractions of these decays: B[B0→K∗0[K+π−]γ] = (4.5±0.3±0.2)×10−5, B[B0→K∗0[K0Sπ0]γ] = (4.4±0.9±0.6)×10−5, B[B+→K∗+[K+π0]γ] = (5.0±0.5±0.4)×10−5, and B[B+→K∗+[K0Sπ+]γ] = (5.4±0.6±0.4)×10−5, where the first uncertainty is statistical, and the second is systematic. The results are consistent with world-average values.

Keyword(s): Radiative penguin ; Electroweak penguin ; Flavor changing neutral current ; FCNC ; EWP