We compute the QCD form factor resumming threshold logarithms in B → Xc + l + νl decays to next-to-leading logarithmic approximation. We present an interpolation formula including soft as well as collinear effects softened by the non-vanishing charm mass which, in the N-space, reads: {Mathematical expression}, where y = (mXc2 - mc2) / (Q2 - mc2), ρ = mc2 / (Q2 - mc2) and Q = EXc + | over(p, →)Xc |. The function A (ρ ; αS) describes soft radiation collinearly enhanced off the charm quark and reduces to the standard double-logarithmic function A (αS) in the massless limit ρ → 0. The function B (αS) describes hard collinear emission off the charm quark, being the standard jet function. D (αS) and Δ (αS) describe soft radiation not collinearly enhanced off the beauty and the charm quark respectively. © 2007 Elsevier B.V. All rights reserved.
Threshold resummation in B → Xc l νl decays / Aglietti, U.; Di Giustino, L.; Ferrera, G.; Renzaglia, A.; Ricciardi, G.; Trentadue, L.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 653:1(2007), pp. 38-52. [10.1016/j.physletb.2007.07.041]
Threshold resummation in B → Xc l νl decays
Trentadue L.
2007-01-01
Abstract
We compute the QCD form factor resumming threshold logarithms in B → Xc + l + νl decays to next-to-leading logarithmic approximation. We present an interpolation formula including soft as well as collinear effects softened by the non-vanishing charm mass which, in the N-space, reads: {Mathematical expression}, where y = (mXc2 - mc2) / (Q2 - mc2), ρ = mc2 / (Q2 - mc2) and Q = EXc + | over(p, →)Xc |. The function A (ρ ; αS) describes soft radiation collinearly enhanced off the charm quark and reduces to the standard double-logarithmic function A (αS) in the massless limit ρ → 0. The function B (αS) describes hard collinear emission off the charm quark, being the standard jet function. D (αS) and Δ (αS) describe soft radiation not collinearly enhanced off the beauty and the charm quark respectively. © 2007 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
