Measurement of B (Bs ?dsX) with Bs semileptonic tagging

Abstract

We report the first direct measurement of the inclusive branching fraction B(Bs?DsX) via Bs tagging in e+e-? (5S) events. Tagging is accomplished through a partial reconstruction of semileptonic decays Bs?DsX??, where X denotes unreconstructed additional hadrons or photons and ? is an electron or muon. With 121.4 fb-1 of data collected at the (5S) resonance by the Belle detector at the KEKB asymmetric-energy e+e- collider, we obtain B(Bs?DsX)=(60.2�5.8�2.3)%, where the first uncertainty is statistical and the second is systematic. � 2022 authors. Published by the American Physical Society.