Perturbative corrections to Λ _b → Λ form factors from QCD light-cone sum rules

Autor(en)

Yu-Ming Wang, Yue-Long Shen

Abstrakt

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

⁺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(en)

Teilchenphysik

Externe Organisation(en)

Technische Universität München, Ocean University of China

Journal

Journal of High Energy Physics

Band

2016

Anzahl der Seiten

51

ISSN

1029-8479

DOI

https://doi.org/10.1007/JHEP02(2016)179

Publikationsdatum

02-2016

Peer-reviewed

Ja

ÖFOS 2012

103012 Hochenergiephysik

Schlagwörter

ASJC Scopus Sachgebiete

Nuclear and High Energy Physics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/2774af40-d88c-48ce-97ec-8f6132314fd1