The Belle II Collaboration

25 July 2020

Abstract: We study e+e−→J/ψ(→µ+µ−) via initial-state radiation (ISR) using a data sample of an integrated luminosity of 37.8 fb^-1 collected with the Belle II detector at the Υ(4S) resonance and nearby. The distributions which represent ISR characteristics between data and MC are consistent. The J/ψ signal yield in data is compatible with our expectation according to MC simulation. We also give the muon identification efficiency corrections as functions of momenta and polar angles of muons. This analysis helps to understand ISR performances at Belle II, and perform the follow-up analysis, i.e., e+e−→π+π−J/ψ.