%AKniehl, B A [Wisconsin Univ., Madison, WI (United States). Dept. of Physics]
%A[Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]
%ASirlin, A [New York Univ., NY (United States). Dept. of Physics]
%D1991
%I; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
%J
%K72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS, WEINBERG LEPTON MODEL, VACUUM POLARIZATION, FERMIONS, PERTURBATION THEORY, WARD IDENTITY, DISPERSION RELATIONS, QUANTUM ELECTRODYNAMICS, QUANTUM CHROMODYNAMICS, REST MASS, RENORMALIZATION, RADIATIVE CORRECTIONS, FUNCTIONS, 662210, UNIFIED THEORIES AND MODELS
%PMedium: X; Size: 11 p.
%TDispersion relations for vacuum-polarization functions in electroweak physics
%XWe propose a class of once-subtracted dispersion relations for the vacuum-polarization functions of massive fermions, in which the subtraction constants are determined explicitly from Ward indentities. We show that in perturbation theory to O({alpha}) and O({alpha}{alpha}{sub s}) this approach, the alternative dispersion relations proposed by Chang, Gaemers, and van Neerven, and dimensional regularization all give the same contributions to electroweak observables such as {Delta}{rho} and {Delta}{rho}. The threshold behaviours of the subtraction integrands are, however, very different and the two dispersion methods are expected to lead to significantly variant estimates of contributions arising form non-perturbative tanti t threshold effects. (orig.).
%0Technical Report
Germany Other: ON: DE92759320; CNN: Contract DE-AC02-76ER00881; Grant PHY-90-17585; TRN: DE9200739 DEN English