Perturbative corrections to Λ <sub>b</sub> → Λ form factors from QCD light-cone sum rules

Author(s)
Yu-Ming Wang, Yue-Long Shen
Abstract

Abstract: We compute radiative corrections to Λ

b → Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ

b-baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ

b-baryon correlation function is justified at leading power in Λ/m

b, with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to-B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at (Formula presented.) shift the Λ

b → Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ

b → Λ from factors we further investigate several decay observables in the electro-weak penguin Λ

b → Λ ℓ

+

transitions in the factorization limit (i.e., ignoring the “non-factorizable” hadronic effects which cannot be expressed in terms of the Λ

b → Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

Organisation(s)
Particle Physics
External organisation(s)
Technische Universität München, Ocean University of China
Journal
Journal of High Energy Physics
Volume
2016
No. of pages
51
ISSN
1029-8479
DOI
https://doi.org/10.1007/JHEP02(2016)179
Publication date
02-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
103012 High energy physics
Keywords
ASJC Scopus subject areas
Nuclear and High Energy Physics
Portal url
https://ucris.univie.ac.at/portal/en/publications/perturbative-corrections-to--b---form-factors-from-qcd-lightcone-sum-rules(2774af40-d88c-48ce-97ec-8f6132314fd1).html