Belle II status and prospects for studies of neutral currents

TL;DR

The paper reviews Belle II's recent measurements of neutral current processes in B meson decays, discusses current status, and outlines future prospects for exploring rare decays and potential new physics signals.

Contribution

It provides an update on Belle II's recent results and future plans for studying neutral current transitions in B meson decays, highlighting new measurements and search strategies.

Findings

Measurements of $B\to K^*\gamma$ and $B\to X_s\gamma$ branching fractions.

Search for $B^+\to K^+\nu\bar\nu$ decays.

Prospects for $B\to K^{*}\tau\tau$ and lepton flavor violating channels.

Abstract

The Belle II experiment at the SuperKEKB energy-asymmetric electron-positron collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. Belle II collected a sample of $362~\mathrm{fb}^{-1}$ at the $\Upsilon(4S)$ resonance between 2019 and 2022, with a maximum peak luminosity of $4.7 \times 10^{34} \mathrm{cm}^{-2}s^{-1}$. Belle II is currently facing a long shutdown period, required for several upgrades of the detector and the collider. Data taking will resume at the end of 2023. We report the recent measurements which involve neutral current transitions in $B$ meson decays. In particular, we present the current status and future prospects for the branching fractions measurements of the radiative decays $B\to K^*\gamma$ and the fully inclusive $B\to X_s\gamma$, the search for $B^+\to K^+\nu\bar \nu$ decays, the measurement of the branching fractions of $B\to J/\psi(\to \ell\ell)K$ and $B\to K^*\ell\ell$. Finally, we show the perspectives of the search for $B\to K^{*}\tau\tau$ and the searches of lepton flavor violating channels $B\to K^{(*)}\ell\ell'$, with $\ell=e, \mu, \tau$.