Measurement of the decays Bs0→J/ψφ(1020), Bs0→J/ ψf2′(1525) and Bs0→J/ψK+K- at Belle

Abstract

We report a measurement of the branching fraction of the decay Bs0→J/ψφ(1020), evidence and a branching fraction measurement for Bs0→J/ψf2′(1525), and the determination of the total Bs0→J/ψK+K- branching fraction, including the resonant and nonresonant contributions to the K+K- channel. We also determine the S-wave contribution within the φ(1020) mass region. The absolute branching fractions are B[Bs0→J/ψφ(1020)]=(1. 25±0.07(stat)±0.08(syst)±0.22(fs))×10 -3, B[Bs0→J/ψf2′(1525)]=(0.26±0.06(stat) ±0.02(syst)±0.05(fs))×10-3, and B[Bs0→J/ψK+K-]=(1.01±0.09(stat)±0. 10(syst)±0.18(fs))×10-3, where the last systematic error is due to the branching fraction of bb̄→Bs(*) Bs(*). The branching fraction ratio is found to be B[Bs0→J/ ψf2′(1525)]/B[Bs0→J/ψφ(1020)]=(21.5±4.9(stat) ±2.6(syst))%. All results are based on a 121.4 fb-1 data sample collected at the Υ(5S) resonance by the Belle experiment at the KEKB asymmetric-energy e+e- collider. © 2013 American Physical Society.