000001611 001__ 1611 000001611 005__ 20190813065717.0 000001611 037__ $$aBELLE2-TALK-CONF-2019-090 000001611 041__ $$aeng 000001611 088__ $$aBELLE2-TALK-DRAFT-2019-080 000001611 100__ $$aAlberto Martini 000001611 245__ $$aDark sector physics with Belle II 000001611 260__ $$aPASCOS 2019$$c2019-07-01 000001611 300__ $$amult. p 000001611 500__ $$a20 min 000001611 520__ $$aThe 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 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. 000001611 8560_ $$fdoris.yangsoo.kim@desy.de 000001611 8564_ $$uhttps://docs.belle2.org/record/1611/files/BELLE2-TALK-CONF-2019-090.pdf