Inclusive semileptonic Λb decays in the Standard Model and beyond

Inclusive semileptonic decays of beauty baryons are studied using the heavy quark expansion to $$ \mathcal{O}\left(1/{m}_b^3\right) $$ O 1 / m b 3 , at leading order in αs. The case of a polarized decaying baryon is examined, with reference to Λb. An extension of the Standard Model effective Hamiltonian inducing b → $$ U\mathrm{\ell}{\overline{\nu}}_{\mathrm{\ell}} $$ U ℓ ν ¯ ℓ transitions (U = u, c and ℓ = e, μ, τ) 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.

HIGHER-ORDERS IN SEMILEPTONIC B-DECAYS

In this paper, on a talk given at Lawrence Berkeley Laboratory, we discuss higher-order non-perturbative corrections in inclusive semileptonic decays of B mesons. First the generic calculation is reviewed and then we identify the relevant hadronic matrix-elements up to [Formula: see text]. For a quantitative analysis of these effects, the value of these new matrix-elements is estimated within an approximation scheme. We investigate the role of so-called "intrinsic-charm" operators in this decay, appearing first at order [Formula: see text] in the heavy-quark expansion. These operators induce an expansion infrared sensitive to the charm quark [Formula: see text]. Parametrically the power corrections complement the estimate of the potential impact of [Formula: see text] contributions, which we will explore. In this context, we draw semiquantitative conclusions for the expected scale of valence weak annihilation contribution in semileptonic B decays. Furthermore the effects on the integrated rate and on kinematic moments are then estimated up to [Formula: see text].

DETERMINATION OF |Vcb| AND RELATED RESULTS FROM BABAR

The CKM matrix element amplitude |Vcb| was determined using the data collected by the BABAR detector. The partial branching fraction, lepton-energy moments, and hadron-mass moments were measured in inclusive semileptonic decays B→Xcℓν. A global fit to a Heavy-Quark-Expansion calculation allowed precise determination of |Vcb|, mb, mc, ℬ(B→Xcℓν) and four non-perturbative parameters.

|Vub| AND |Vcb|, CHARM COUNTING AND LIFETIME DIFFERENCES IN INCLUSIVE BOTTOM HADRON DECAYS

Inclusive bottom hadron decays are analyzed based on the heavy quark effective field theory (HQEFT). Special attentions in this paper are paid to the b→u transitions and nonspectator effects. As a consequence, the CKM quark mixing matrix elements |Vub| and |Vcb| are reliably extracted from the inclusive semileptonic decays B→Xueν and B→Xceν. Various observables, such as the semileptonic branch ratio BSL, the lifetime differences among B-, B0, Bsand Λbhadrons, the charm counting nc, are predicted and found to be consistent with the present experimental data.