# EPS-HEP2019

Jul 10 – 17, 2019
Ghent
Europe/Brussels timezone

## Missing energy and electroweak penguin modes in early Belle II data

Jul 12, 2019, 9:55 AM
20m
Campus Ledeganck - Aud. 5 (Ghent)

### Campus Ledeganck - Aud. 5

#### Ghent

Parallel talk Flavour Physics and CP Violation

### Speaker

William Sutcliffe (Karlsruhe Institute of Technology (KIT))

### Description

The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of $5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$, and Belle II has recorded a data sample of about 0.5 fb$^{-1}$. Main operation of SuperKEKB has started in March 2019.

In this presentation we show first results from studying missing energy signatures, such as leptonic and semileptonic B meson decays based on early Belle II data. We report first studies on re-measuring important standard candle processes, such as the abundant inclusive $B\to X\ell\nu$ and $B\to D^*\ell\nu$ decays. Furthermore, we will also present an overview of the semileptonic B decays that will be measured in the upcoming years at Belle II and discuss prospects for important B-anomalies like R(D) and R(D*), as well as other tests of lepton flavor universality. Early physics goals of the Belle II physics program are also to rediscover rare B decays. Especially radiative $b\to s \gamma$ decays can be measured on a small dataset and in the near future Belle II can provide independent tests of anomalies in $b\to s\ell \ell$ decays. Ultimately, the clean Belle II environment will allow to study modes with large missing energy such as $B\to K^\ast \nu \bar\nu$.

### Primary authors

Ida Peruzzi (Laboratori Nazionali di Frascati dell'INFN) William Sutcliffe (Karlsruhe Institute of Technology (KIT))