Measurements of branching fractions and decay amplitudes in B→J/ψ K* decays

The branching fractions and the decay amplitudes of B --> J/psiK* decays are measured in a 29.4 fb(-1) data sample collected with the Belle detector at the KEKB electron-positron collider. The decay amplitudes of helicity states of the J/psiK* system are determined from the full angular distribution of the final state particles in the transversity basis. The branching fractions are measured to be (1.29 +/- 0.05 +/- 0.13) x 10(-3) for neutral mesons and (1.28 +/- 0.07 +/- 0.14) x 10(-3) for charged mesons. The measured longitudinal and transverse (perpendicular to the transversity plane) amplitudes are \A(0)\(2) = 0.62 +/- 0.02 +/- 0.03 and \A(perpendicular to)\(2) = 0.19 +/- 0.02 +/- 0.03, respectively. The value of \A(perpendicular to)\(2) shows that the CP even component dominates in the B-0 --> J/psiK*(0)(K(S)pi(0)) decay. (C) 2002 Elsevier Science B.V. All rights reserved.