Form factors and QCD in spacelike and timelike regions

被引:61
作者
Bakulev, AP [1 ]
Radyushkin, AV
Stefanis, NG
机构
[1] Joint Inst Nucl Res, Bogolyubov Lab Theoret Phys, Dubna 141980, Russia
[2] Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA
[3] Jefferson Lab, Theory Grp, Newport News, VA 23606 USA
[4] Ruhr Univ Bochum, Inst Theoret Phys 2, D-44780 Bochum, Germany
关键词
D O I
10.1103/PhysRevD.62.113001
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We analyze the basic hard exclusive processes, the pi gamma* gamma -transition and the pion and nucleon electromagnetic form factors. and discuss the analytic continuation of QCD formulas from the spacelike q(2)<0 to the timelike region q(2)>0 of the relevant momentum transfers. We describe the construction of the timelike version of the coupling constant <alpha>(s). We Show that due to the analytic continuation of the collinear logarithms, each eigenfunction of the evolution equation acquires a phase factor curd investigate the resulting interference effects which an shown to be very small. We find 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, we use a QCD sum rule inspired model and show that there are noncanceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region.
引用
收藏
页码:1 / 14
页数:14
相关论文
共 96 条
[81]  
RADYUSHKIN AV, 1994, TH9413 CEBAF
[82]  
RADYUSHKIN AV, HEPPH9907228
[83]   FIELD-THEORY APPROACH TO PROCESSES WITH LARGE MOMENTUM-TRANSFER .3. GAUGE-THEORIES [J].
EFREMOV, AV ;
RADYUSHKIN, AV .
THEORETICAL AND MATHEMATICAL PHYSICS, 1980, 44 (03) :774-784
[84]  
REYA E, 1981, PHYS REP, V69, P196
[85]  
SARMADI MH, 1982, THESIS PITTSBURGH U
[86]   QCD AND RESONANCE PHYSICS - APPLICATIONS [J].
SHIFMAN, MA ;
VAINSHTEIN, AI ;
ZAKHAROV, VI .
NUCLEAR PHYSICS B, 1979, 147 (05) :448-518
[87]   QCD AND RESONANCE PHYSICS - THEORETICAL FOUNDATIONS [J].
SHIFMAN, MA ;
VAINSHTEIN, AI ;
ZAKHAROV, VI .
NUCLEAR PHYSICS B, 1979, 147 (05) :385-447
[88]   Renormalization group, causality, and nonpower perturbation expansion in QFT [J].
Shirkov, DV .
THEORETICAL AND MATHEMATICAL PHYSICS, 1999, 119 (01) :438-447
[89]   Analytic model for the QCD running coupling with universal (alpha)over-bar(s)(0) value [J].
Shirkov, DV ;
Solovtsov, IL .
PHYSICAL REVIEW LETTERS, 1997, 79 (07) :1209-1212
[90]  
SHIRKOV DV, JINRE2200046