Results and prospects of radiative and electroweak penguin decays at Belle II

TL;DR

This paper discusses the early results and future potential of studying rare flavor-changing neutral current decays, specifically radiative and electroweak penguin decays, at the upgraded Belle II experiment.

Contribution

It reports the first reconstruction of a $B\to K^{*}\gamma$ signal at Belle II and outlines future prospects for these rare decay measurements.

Findings

First $B\to K^{*}\gamma$ signal reconstructed at Belle II

Demonstrates Belle II's capability to detect rare decays

Provides outlook for future measurements of electroweak penguin decays

Abstract

The $b\to s(d)$ quark-level transitions are flavor-changing neutral current processes, which are not allowed at tree level in the standard model. These processes are very rare and constitute a potential probe for new physics. Belle II at SuperKEKB is a substantial upgrade of the Belle experiment. It aims to collect 50 ab$^{-1}$ of data with a design peak luminosity of $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ that is 40 times more than its predecessor. It has been recording data since 2019 and during these early days of the experiment, efforts are being made to detect early signals of the above decays. We report the first reconstrution in Belle II data of a $B\to K^{*}\gamma$ signal as well as future prospects for radiative and electroweak decays at Belle II.