Semileptonic and nonleptonic weak decays of Λb0

Abstract

The recent experimental developments require a more precise theoretical study of weak decays of heavy baryon Λb0. In this work, we provide an updated and systematic analysis of both the semi-leptonic and nonleptonic decays of Λb0 into baryons Λc+, Λ, p, and n. The diquark approximation is adopted so that the methods developed in the B meson system can be extended into the baryon system. The baryon-to-baryon transition form factors are calculated in the framework of a covariant light-front quark model. The form factors f3, g3 can be extracted and are found to be non-negligible. The semileptonic processes of Λb0→Λc+(p)l-νl are calculated and the results are consistent with the experiment. We study the nonleptonic processes within the QCD factorization approach. The decay amplitudes are calculated at the next-to-leading order in strong coupling constant αs. We calculate the nonleptonic decays of Λb0 into a baryon and a s-wave meson (pseudoscalar or vector) including 44 processes in total. The branching ratios and direct CP asymmetries are predicted. The numerical results are compared to the experimental data and those in the other theoretical approaches. Our results show validity of the diquark approximation and application of QCD factorization approach into the heavy baryon system.