Sudakov Resummation for Subleading SCET Currents and HeavytoLight Form Factors
Abstract
The hardscattering contributions to heavytolight form factors at large recoil are studied systematically in softcollinear effective theory (SCET). Large logarithms arising from multiple energy scales are resummed by matching QCD onto SCET in two stages via an intermediate effective theory. Anomalous dimensions in the intermediate theory are computed, and their form is shown to be constrained by conformal symmetry. Renormalizationgroup evolution equations are solved to give a complete leadingorder analysis of the hardscattering contributions, in which all single and double logarithms are resummed. In two cases, spinsymmetry relations for the softoverlap contributions to form factors are shown not to be broken at any order in perturbation theory by hardscattering corrections. Oneloop matching calculations in the two effective theories are performed in sample cases, for which the relative importance of renormalizationgroup evolution and matching corrections is investigated. The asymptotic behavior of Sudakov logarithms appearing in the coefficient functions of the softoverlap and hardscattering contributions to form factors is analyzed.
 Publication:

Journal of High Energy Physics
 Pub Date:
 July 2004
 DOI:
 10.1088/11266708/2004/07/081
 arXiv:
 arXiv:hepph/0404217
 Bibcode:
 2004JHEP...07..081H
 Keywords:

 Renormalization Group Weak Decays BPhysics QCD;
 High Energy Physics  Phenomenology
 EPrint:
 50 pages, 10 figures