Marcello Campajola

24 February 2020
Conference on Neutrino and Nuclear Physics 2020 (CNNP2020)

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−2s−1 and the Belle II experiment aims to record 50 ab−1 of data, a factor of 50 more than its predecessor. Main operation of SuperKEKB has started in March 2019, with the full detector installed; this first running period ended in July. The machine reached a peak luminosity of 1.2×1034 cm−2s−1, and Belle II recorded a data sample of about 6.5 fb−1. Data taking will resume in October 2019. Already this early data set, with specifically designed triggers, offers the possibility to search for a large variety of dark sector particles in the GeV mass range, complementary to LHC and to dedicated low energy experiments; these searches will benefit from more data which will be accumulated in the upcoming Fall/Winter run. This talk will review the state of the dark sector searches at Belle II with a focus on the discovery potential of the early data, and show the first results