Matching of the shape function

Citation
U. Aglietti et G. Ricciardi, Matching of the shape function, PHYS LETT B, 466(2-4), 1999, pp. 313-318
Citations number
24
Categorie Soggetti
Physics
Journal title
PHYSICS LETTERS B
ISSN journal
03702693 → ACNP
Volume
466
Issue
2-4
Year of publication
1999
Pages
313 - 318
Database
ISI
SICI code
0370-2693(19991104)466:2-4<313:MOTSF>2.0.ZU;2-6
Abstract
The shape function f(k(+)) describes Fermi motion effects in inclusive semi -leptonic decays such as B --> X-u + e + v near the end-point of the lepton spectrum. We compute the leading one-loop corrections to the shape functio n f(k(+)) in the effective theory with a hard cut-off regularization. The m atching constant onto full QCD is infrared safe, i.e. the leading infrared singularity represented by the term log(2)k(+) cancels in the difference of integrals. We compare the hard cut-off result with the result in dimension al regularization, the latter containing an additional factor of two in the coefficient of the log(2)k(+) term, and consequently requiring an oversubt raction. (C) 1999 Published by Elsevier Science B.V. All rights reserved.