Study of B[superscript ±]→J/ψπ[superscript ±] and B[superscript ±]→J/ψK[superscript ±] Decays: Measurement of the Ratio of Branching Fractions and Search for Direct CP Violation

Abstract

We study B[superscript ±]→J/ψπ[superscript ±] and B[superscript ±]→J/ψK[superscript ±] decays in a sample of about 89×10[superscript 6] BB̅ pairs collected with the BABAR detector at the PEP-II asymmetric B factory at SLAC. We observe a signal of 244±20 B[superscript ±]→J/ψπ[superscript ±] events and determine the ratio B(B[superscript ±]→J/ψπ[superscript ±])/B(B[superscript ±]→J/ψK±) to be [5.37±0.45(stat)±0.11(syst)]%. The charge asymmetries for the B[superscript ±]→J/ψπ[superscript ±] and B[superscript ±]→J/ψ[superscript ±] decays are determined to be A[subscript π]=0.123±0.085(stat)±0.004(syst) and A[subscript K]=0.030±0.015(stat)±0.006(syst), respectively.