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Title: Evolution equation for the B-meson distribution amplitude in the heavy-quark effective theory in coordinate space

Journal Article · · Physical Review. D, Particles Fields
 [1];  [2]
  1. Department of Mathematical Sciences, University of Liverpool, Liverpool, L69 3BX (United Kingdom)
  2. Department of Physics, Juntendo University, Inba-gun, Chiba 270-1695 (Japan)

The B-meson distribution amplitude (DA) is defined as the matrix element of a quark-antiquark bilocal light-cone operator in the heavy-quark effective theory, corresponding to a long-distance component in the factorization formula for exclusive B-meson decays. The evolution equation for the B-meson DA is governed by the cusp anomalous dimension as well as the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-type anomalous dimension, and these anomalous dimensions give the ''quasilocal'' kernel in the coordinate-space representation. We show that this evolution equation can be solved analytically in the coordinate space, accomplishing the relevant Sudakov resummation at the next-to-leading logarithmic accuracy. The quasilocal nature leads to a quite simple form of our solution which determines the B-meson DA with a quark-antiquark light-cone separation t in terms of the DA at a lower renormalization scale {mu} with smaller interquark separations zt (z{<=}1). This formula allows us to present rigorous calculation of the B-meson DA at the factorization scale {approx}{radical}(m{sub b{Lambda}QCD}) for t less than {approx}1 GeV{sup -1}, using the recently obtained operator product expansion of the DA as the input at {mu}{approx}1 GeV. We also derive the master formula, which reexpresses the integrals of the DA at {mu}{approx}{radical}(m{sub b{Lambda}QCD}) for the factorization formula by the compact integrals of the DA at {mu}{approx}1 GeV.

OSTI ID:
21407955
Journal Information:
Physical Review. D, Particles Fields, Vol. 81, Issue 11; Other Information: DOI: 10.1103/PhysRevD.81.114009; (c) 2010 The American Physical Society; ISSN 0556-2821
Country of Publication:
United States
Language:
English