Belle II studies of missing energy decays and searches for dark photon production

TL;DR

The Belle II experiment aims to explore physics beyond the Standard Model by studying missing energy decays and searching for dark photon candidates with unprecedented data precision.

Contribution

This paper discusses Belle II's capabilities and plans for investigating missing energy decays and dark photon searches with its upcoming large data sample.

Findings

Potential to observe rare decays with missing energy

Sensitivity to dark photon production

Enhanced precision in B decay measurements

Abstract

The Belle II experiment at the SuperKEKB collider is a major upgrade of the KEK "$B$ factory" facility in Tsukuba, Japan. The machine is designed for an instantaneous luminosity of $8\times 10^{35}$~cm$^{-2}$\,s$^{-1}$, and the experiment is expected to accumulate a data sample of about 50 ab$^{-1}$ well within the next decade. With this amount of data, decays sensitive to physics beyond the Standard Model can be studied with unprecedented precision. One promising set of modes are physics processes with missing energy such as $B^+\to\tau^+\nu_{\tau}$, $B\to D^{(*)}\tau\nu_{\tau}$, and $B\to K^{(*)}\nu\bar\nu$ decays. The Belle II data also allows searches for candidates for the dark photon, the gauge mediator of a hypothetical dark sector, which has received much attention in the context of dark matter models.