Inclusive semileptonic Λb decays in the Standard Model and beyond
Pietro Colangelo, Fulvia De Fazio, Francesco Loparco
Abstract
A bstract Inclusive semileptonic decays of beauty baryons are studied using the heavy quark expansion to $$ \mathcal{O}\left(1/{m}_b^3\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:msubsup> <mml:mi>m</mml:mi> <mml:mi>b</mml:mi> <mml:mn>3</mml:mn> </mml:msubsup> </mml:mrow> </mml:mfenced> </mml:math> , at leading order in α s . The case of a polarized decaying baryon is examined, with reference to Λ b . An extension of the Standard Model effective Hamiltonian inducing b → $$ U\mathrm{\ell}{\overline{\nu}}_{\mathrm{\ell}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>U</mml:mi> <mml:mi>ℓ</mml:mi> <mml:msub> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>ℓ</mml:mi> </mml:msub> </mml:math> 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.