The branching fractions and the decay amplitudes of B→J/ψK∗ 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/ψK∗ 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)×10−3 for neutral mesons and (1.28±0.07±0.14)×10−3 for charged mesons. The measured longitudinal and transverse (perpendicular to the transversity plane) amplitudes are |A0|2=0.62±0.02±0.03 and |A⊥|2=0.19±0.02±0.03, respectively. The value of |A⊥|2 shows that the CP even component dominates in the decay.
Physics Letters B / Volume 538, Issues 1–2, P.11–20