Bound on the Ratio of Decay Amplitudes for B̅[superscript 0]→J/ψK[superscript *0] and B[superscript 0]→J/ψ[superscript *0]

Abstract

We have measured the time-dependent decay rate for the process B→J/ψK[superscript *0](892) in a sample of about 88×10[superscript 6] Υ(4S)→BB̅ decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In this sample we study flavor-tagged events in which one neutral B meson is reconstructed in the J/ψK[superscript *0] or J/ψK̅[superscript *0] final state. We measure the coefficients of the cosine and sine terms in the time-dependent asymmetries for J/ψK[superscript *0] and J/ψK̅[superscript *0], find them to be consistent with the standard model expectations, and set upper limits at 90% confidence level (C.L.) on the decay amplitude ratios |A(B̅[superscript 0]→J/ψK[superscript *0])|/|A(B[superscript 0]→J/ψK[superscript *0])|<0.26 and |A(B[superscript 0]→J/ψK̅[superscript *0])|/|A(B̅[superscript 0]→J/ψK̅[superscript *0])|<0.32. For a single ratio of wrong-flavor to favored amplitudes for B[superscript 0] and B̅[superscript 0] combined, we obtain an upper limit of 0.25 at 90% C.L.