The Belle II experiment: status and prospects

A Martini

doi:10.1088/1742-6596/1137/1/012035

Abstract

In this article the Belle II experiment will be described and its status and physics prospects will be presented. Belle II is situated in Japan, at the KEK laboratory and it is the upgraded version of the Belle experiment. It uses a new collider named SuperKEKB, a new generation of B-factory based on the innovative Nano-Beam scheme technique, which is expected to collect an integrated luminosity of 50 ab −1. Using this amount of data, together with improved detector performances, it will be possible to provide important contributions about several flavour physics topics (i.e. UT angles, CKM matrix elements, FCNC processes, LFV studies, etc.) through high precision measurements. The main aim is to investigate new physics scenarios and validate highly suppressed SM predictions. The experiment is almost completely assembled; it already took the first data without the vertex detector installed while the data taking will start in February 2019.

Highlights

An essential role in the understanding of the Standard Model (SM) and its mechanisms is played by the heavy flavour physics
Phase 2: it ended in July 2018 and some physics data have been collected without the silicon vertex detector installed
SuperKEKB uses asymmetric electron and positron beams resulting in a boost of the center of mass (CM) system corresponding to a factor βγ = 0.28 in order to enable time-dependent CP violation measurements

Summary

Introduction

An essential role in the understanding of the Standard Model (SM) and its mechanisms is played by the heavy flavour physics. Experiments at B-factories investigated deeply this field (BaBar using PEP II and Belle using KEKB) producing important discoveries concerning the B meson physics and more. Many SM predictions have still to be verified and the investigation of New Physics (NP) processes is crucial. For those reasons a second generation of B-factories is rising together with a corresponding experiment. The new SuperKEKB collider [1] (Fig. 1 left), together with an improved detector system with respect to its predecessor Belle, have been assembled and tested at KEK, and it plays a key role in the investigation of NP. Phase 2: it ended in July 2018 and some physics data have been collected without the silicon vertex detector installed. Phase 3: it will start in February 2019 and it consists in the data taking with the whole detector installed

Collider and detector

Physics program

Findings

Conclusions