Inclusive semileptonic ${\Lambda }_b$ decays in the Standard Model and beyond

Abstract

Inclusive semileptonic decays of beauty baryons are studied using the heavy quark expansion to $\mathcal{O}(1/m_b^3)$, at leading order in ${\alpha }_s$. The case of a polarized decaying baryon is examined, with reference to ${\Lambda }_b$. An extension of the Standard Model effective Hamiltonian inducing $b\to U\ell {\bar{\nu }}_{\ell }$ transitions ($U=u,c$ and $\ell =e,\mu ,\tau$) is considered, which comprises the full set of D=6 semileptonic operators with left-handed neutrinos. The effects of the new operators in several observables are described.

Comments: 50 pages, 12 figures. Corrected eq. (C.5)