skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Form factors and QCD in spacelike and timelike region

Abstract

The authors analyze the basic hard exclusive processes: {pi}{gamma}{sup *}{gamma}-transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q{sup 2} < 0 to the timelike region q{sup 2} > 0 of the relevant momentum transfers. They describe the construction of the timelike version of the coupling constant {alpha}{sub s}. They show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. They found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, they use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region.

Authors:
; ;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
754870
Report Number(s):
DOE/ER/40150-1418; JLAB-THY-00-12; RUB-TPII-06/00; hep-ph/0005085
TRN: US0100880
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys.Rev.D62:113001,2000; Journal Volume: D; Journal Issue: 62; Other Information: Submitted to Phys.Rev.D62:113001,2000; PBD: 1 May 2000
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COUPLING CONSTANTS; EIGENFUNCTIONS; ELECTROMAGNETIC FORM FACTORS; FORM FACTORS; MOMENTUM TRANSFER; NUCLEONS; PIONS; POWER FACTOR; QUANTUM CHROMODYNAMICS; SUM RULES

Citation Formats

Bakulev, A P, Radyushkin, A V, and Stefanis, N G. Form factors and QCD in spacelike and timelike region. United States: N. p., 2000. Web. doi:10.1103/PhysRevD.62.113001.
Bakulev, A P, Radyushkin, A V, & Stefanis, N G. Form factors and QCD in spacelike and timelike region. United States. doi:10.1103/PhysRevD.62.113001.
Bakulev, A P, Radyushkin, A V, and Stefanis, N G. Mon . "Form factors and QCD in spacelike and timelike region". United States. doi:10.1103/PhysRevD.62.113001. https://www.osti.gov/servlets/purl/754870.
@article{osti_754870,
title = {Form factors and QCD in spacelike and timelike region},
author = {Bakulev, A P and Radyushkin, A V and Stefanis, N G},
abstractNote = {The authors analyze the basic hard exclusive processes: {pi}{gamma}{sup *}{gamma}-transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q{sup 2} < 0 to the timelike region q{sup 2} > 0 of the relevant momentum transfers. They describe the construction of the timelike version of the coupling constant {alpha}{sub s}. They show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. They found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, they use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region.},
doi = {10.1103/PhysRevD.62.113001},
journal = {Phys.Rev.D62:113001,2000},
number = 62,
volume = D,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2000},
month = {Mon May 01 00:00:00 EDT 2000}
}