Incorporation of QCD effects in basic corrections of the electroweak theory

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.48.307· OSTI ID:6430623

Fanchiotti, S ^[1]; Kniehl, B ^[2]; Sirlin, A ^[3]

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1. Theory Division, CERN, 1211 Geneva 23 (Switzerland)
2. II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 2000 Hamburg 50 (Germany)
3. Department of Physics, New York University, 4 Washington Place, New York, New York 10003 (United States)

We study the incorporation of QCD effects in the basic electroweak corrections [Delta][ital [cflx r]], [Delta][ital [cflx r]][sub [ital W]], and [Delta][ital r]. They include perturbative [ital O]([alpha][alpha][sub [ital s]]) contributions and [ital t[bar t]] threshold effects. The latter are studied in the resonance and Green-function approaches, in the framework of dispersion relations that automatically satisfy relevant Ward identities. Refinements in the treatment of the electroweak corrections, in both the modified minimal subtraction (M[bar S]) and the on-shell schemes of renormalization, are introduced, including the decoupling of the top quark in certain amplitudes, its effect on [ital [cflx e]][sup 2]([ital m][sub [ital Z]]) and sin[sup 2][cflx [theta]][sub [ital W]]([ital m][sub [ital Z]]), the incorporation of recent results on the leading irreducible [ital O]([alpha][sup 2]) corrections, and simple expressions for the residual, i.e., nonelectromagnetic,'' parts of [Delta][ital [cflx r]], [Delta][ital [cflx r]][sub [ital W]], and [Delta][ital r]. The results are used to obtain accurate values for [ital m][sub [ital W]] and sin[sup 2][cflx [theta]][sub [ital W]]([ital m][sub [ital Z]]), as functions of [ital m][sub [ital t]] and [ital m][sub [ital H]]. The higher-order effects induce shifts in these parameters comparable to the expected experimental accuracy, and they increase the prediction for [ital m][sub [ital t]] derived from current measurements. The M[bar S] and the on-shell calculations of [Delta][ital r], in a recently proposed formulation, are compared and found to be in excellent agreement over the wide ranges 60 GeV [le][ital m][sub [ital H]][le]1 TeV, [ital m][sub [ital Z]][le][ital m][sub [ital t]][le]250 GeV.

• OSTI ID: 6430623
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 48:1; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

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PARTICLE MODELS
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
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