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Title: Heavy-to-light form factors: Sum rules on the light cone and beyond

Abstract

We report the first systematic analysis of the off-light-cone effects in sum rules for heavy-to-light form factors. These effects are investigated in a model based on scalar constituents, which allows a technically rather simple analysis but has the essential features of the analogous QCD calculation. The correlator relevant for the extraction of the heavy-to-light form factor is calculated in two different ways: first, by adopting the full Bethe-Salpeter amplitude of the light meson and, second, by performing the expansion of this amplitude near the light cone x{sup 2}=0. We demonstrate that the contributions to the correlator from the light-cone term x{sup 2}=0 and the off-light-cone terms x{sup 2}{ne}0 have the same order in the 1/m{sub Q} expansion. The light-cone correlator, corresponding to x{sup 2}=0, is shown to systematically overestimate the full correlator, the difference being {approx}{lambda}{sub QCD}/{delta}, with {delta} the continuum subtraction parameter of order 1 GeV. Numerically, this difference is found to be 10 divide 20%.

Authors:
 [1];  [1];  [2];  [3]
  1. Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050, Vienna (Austria)
  2. (Russian Federation)
  3. INFN, Sezione di Roma III, Via della Vasca Navale 84, I-00146, Rome (Italy)
Publication Date:
OSTI Identifier:
21020515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevD.75.096002; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; BETHE-SALPETER EQUATION; FORM FACTORS; GEV RANGE; LIGHT CONE; MESONS; QUANTUM CHROMODYNAMICS; SUM RULES

Citation Formats

Lucha, Wolfgang, Melikhov, Dmitri, Nuclear Physics Institute, Moscow State University, 119992, Moscow, and Simula, Silvano. Heavy-to-light form factors: Sum rules on the light cone and beyond. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.096002.
Lucha, Wolfgang, Melikhov, Dmitri, Nuclear Physics Institute, Moscow State University, 119992, Moscow, & Simula, Silvano. Heavy-to-light form factors: Sum rules on the light cone and beyond. United States. doi:10.1103/PHYSREVD.75.096002.
Lucha, Wolfgang, Melikhov, Dmitri, Nuclear Physics Institute, Moscow State University, 119992, Moscow, and Simula, Silvano. Tue . "Heavy-to-light form factors: Sum rules on the light cone and beyond". United States. doi:10.1103/PHYSREVD.75.096002.
@article{osti_21020515,
title = {Heavy-to-light form factors: Sum rules on the light cone and beyond},
author = {Lucha, Wolfgang and Melikhov, Dmitri and Nuclear Physics Institute, Moscow State University, 119992, Moscow and Simula, Silvano},
abstractNote = {We report the first systematic analysis of the off-light-cone effects in sum rules for heavy-to-light form factors. These effects are investigated in a model based on scalar constituents, which allows a technically rather simple analysis but has the essential features of the analogous QCD calculation. The correlator relevant for the extraction of the heavy-to-light form factor is calculated in two different ways: first, by adopting the full Bethe-Salpeter amplitude of the light meson and, second, by performing the expansion of this amplitude near the light cone x{sup 2}=0. We demonstrate that the contributions to the correlator from the light-cone term x{sup 2}=0 and the off-light-cone terms x{sup 2}{ne}0 have the same order in the 1/m{sub Q} expansion. The light-cone correlator, corresponding to x{sup 2}=0, is shown to systematically overestimate the full correlator, the difference being {approx}{lambda}{sub QCD}/{delta}, with {delta} the continuum subtraction parameter of order 1 GeV. Numerically, this difference is found to be 10 divide 20%.},
doi = {10.1103/PHYSREVD.75.096002},
journal = {Physical Review. D, Particles Fields},
number = 9,
volume = 75,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}