Measurement of the B-->J/psi K*(892) Decay Amplitudes

We present a measurement of the decay amplitudes in B → J/ψ K*(892) channels using 20.7 fb-1 of data collected at the Υ(4S) resonance with the BABAR detector at PEP-II. We measure a P-wave fraction R(perpendicular) = (16.0 ± 3.2 ± 1.4)% and a longitudinal polarization fraction (59.7 ± 2.8 ± 2.4)%. The measurement of a relative phase that is neither 0 nor π, φ(parallel) = 2.50 ± 0.20 ± 0.08 radians, favors a departure from the factorization hypothesis. Although the decay B → J/ψ Kπ proceeds mainly via K*(892), there is also evidence for K*2(1430) and Kπ S-wave contributions