Polarization effects in the cascade decay Lambda_b -> Lambda(-> p pi-) + J/psi(-> l+ l-) in the covariant confined quark model

Understand

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.