Dark Sector Physics at the Belle II Experiment

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 $8\times 10^{35}$ 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. 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 the Large Hadron Collider (LHC) and dedicated low energy experiments; these searches will benefit from more data in the process of being accumulated. 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.

Comments: 6 pages, 5 figures. To appear in the proceedings of the XXXIII workshop of "Les Rencontres des Physique de la Vallee d'Aoste"