Asymptotic behavior of Feynman amplitudes in gauge theories

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6245163

Sen, A

In this dissertation we investigate the asymptotic behavior of the Feynman amplitudes in perturbation theory. It contains two parts. In the first part we compute the asymptotic behavior of the on shell quark form factor, in the limit of large momentum transfer (Sudakov form factor) in non-Abelian gauge theories. We ignore terms which are suppressed by a power of momentum transfer, but keep all non leading logarithms of the momentum transfer and all powers of the coupling constant. Our result shows that the form factor goes down to zero faster than any power of the momentum transfer, as the momentum transfer goes to infinity. In the second part, we calculate the asymptotic behavior of e/sup +/e/sup -/ amplitude in massive QED, in the limit of large center of mass energy and finite momentum transfer. We show that, although the individual Feynman diagrams contributing to the amplitude contains two logs of center of mass energy per loop, they cancel in the sum of all diagrams, and the final amplitude contains only one log per loop. We also sum up the logs in the leading logarithmic approximation and show that the result is a Regge behavior.

• Research Organization: State Univ. of New York, Stony Brook (USA)
• OSTI ID: 6245163
• Country of Publication: United States
• Language: English

Related Subjects

645400* -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMPTOTIC SOLUTIONS
DIAGRAMS
ELECTRODYNAMICS
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
FEYNMAN DIAGRAM
FIELD THEORIES
FORM FACTORS
INTERACTIONS
LEPTON-LEPTON INTERACTIONS
MOMENTUM TRANSFER
PARTICLE INTERACTIONS
PARTICLE PROPERTIES
PERTURBATION THEORY
POSTULATED PARTICLES
QUANTUM ELECTRODYNAMICS
QUANTUM FIELD THEORY
QUARKS
REGGE POLES