Abstract

Using a sample of 448.1×106 ψ(2S) events collected with the BESIII detector, we perform a study of the decay J/ψ→K+K− via ψ(2S)→π+π−J/ψ. The branching fraction of J/ψ→K+K− is determined to be BK+K−=(3.072±0.023(stat)±0.050(syst))×10−4, which is consistent with previous measurements but with significantly improved precision. Published by the American Physical Society 2024