Measurement of the absolute branching fraction of the inclusive decay Λc+ → Λ+X

Abstract

Based on an e+e- collision data sample corresponding to an integrated luminosity of 567 pb-1 taken at the center-of-mass energy of s=4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay Λc+→Λ+X to be B(Λc+→Λ+X)=(38.2-2.2+2.8±0.9)% using the double-tag method, where X refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain ACP≡[B(Λc+→Λ+X)-B(Λc-→Λ+X)]/[B(Λc+→Λ+X)+B(Λc-→Λ+X)]=(2.1-6.6+7.0±1.6)%, a statistically limited result with no evidence of CP violation.