Stefano Lacaprara

08 May 2019
FPCP 2019

Abstract: 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 × 1035 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 × 1033 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. This early data set is used to establish the performance of the detector in terms of reconstruction efficiency of final states of interest for the measurement of time dependent CP violation, such as J/ψK(∗)0 , η 0Ks, and φKs. A first assessment of the B flavor tagging capabilities of the experiment will be given, along with estimates of the Belle II sensitivity to the CKM angles φ1/β and φ2/α and to potential New Physics contributions in penguin amplitudes dominated decays and in b → sγ transitions.

Note: 12+3 min