Abstract

We calculate the invariant and helicity amplitudes for the nonleptonic decay Lambda(b) -> Lambda + J/psi, psi(2S) in the covariant confined quark model. We discuss joint angular decay distributions in the cascade decay Lambda(b) -> Lambda(-> p pi(-)) + J/psi, psi(2S)(-> l(+)l(-)) and calculate some of the asymmetry parameters that characterize the joint angular decay distribution. We confirm expectations from the naive quark model that the transitions into the lambda(Lambda) = 1/2 helicity states of the daughter baryon Lambda are strongly suppressed leading to a near maximal negative polarization of the Lambda. For the same reason the azimuthal correlation between the two decay planes spanned by (p pi(-)) and (l(+)l(-)) is negligibly small. We provide form factor results for the whole accessible q(2) range. Our results are close to lattice results at minimum recoil and light-cone sum rule results at maximum recoil. A new feature of our analysis is that we include lepton mass effects in the calculation, which allows us to also describe the cascade decay Lambda(b) -> Lambda(-> p pi(-)) + psi(2S)(-> tau(+)tau(-)).