The semi-leptonic and non-leptonic weak decays of $\Lambda_b^0$

TL;DR

This paper provides a comprehensive theoretical analysis of both semi-leptonic and non-leptonic weak decays of the heavy baryon b0, using a covariant light-front quark model and QCD factorization, aligning well with experimental data.

Contribution

It extends methods from B meson decays to b0 decays, calculating form factors and decay amplitudes with improved precision and including next-to-leading order effects.

Findings

Form factors _3, _3 are significant and non-negligible.

Semi-leptonic decay results agree with experimental measurements.

Predicted branching ratios and CP asymmetries match observed data.

Abstract

The recent experimental developments require a more precise theoretical study of weak decays of heavy baryon $\Lambda_b^0$. In this work, we provide an updated and systematic analysis of both the semi-leptonic and nonleptonic decays of $\Lambda^0_b$ into baryons $\Lambda^+_c$, $\Lambda$, $p$, 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 $f_3, ~g_3$ can be extracted and are found to be non-negligible. The semi-leptonic processes of $\Lambda^0_b\to \Lambda^+_c(p)l^-\bar\nu_l$ are calculated and the results are consistent with the experiment. We study the non-leptonic processes within the QCD factorization approach. The decay amplitudes are calculated at the next-to-leading order in strong coupling constant $\alpha_s$. We calculate the non-leptonic decays of $\Lambda^0_b$ 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.