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(-)).

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

SANTORELLI, PIETRO
2013

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(-)).
File in questo prodotto:
File Dimensione Formato  
2013-03.pdf

accesso aperto

Tipologia: Documento in Post-print
Licenza: Dominio pubblico
Dimensione 519.36 kB
Formato Adobe PDF
519.36 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/599491
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 50
  • ???jsp.display-item.citation.isi??? 42
social impact