Implications of precision electroweak experiments for m sub t ,. rho. sub 0 , sin sup 2. theta. sub W , and grand unification

Journal Article · Thu Aug 01 00:00:00 EDT 1991 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.44.817· OSTI ID:5451276

Langacker, P; Luo, M ^[1]

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1. University of Pennsylvania, Philadelphia, Pennsylvania 19104 (US)

The implications of precision {ital Z}-pole, {ital W}-mass, and weak-neutral-current data for SU(2){times}U(1) models are described. Within the minimal model one finds sin{sup 2}{cflx {theta}}{sub {ital W}}({ital M}{sub {ital Z}})=0.2334{plus minus}0.0008 in the modified minimal subtraction scheme or sin{sup 2}{theta}{sub {ital W}}==1{minus}{ital M}{sub {ital W}}{sup 2}/{ital M}{sub {ital Z}}{sup 2}=0.2291{plus minus}0.0034 in the on-shell scheme, where the uncertainties include the {ital m}{sub {ital t}} and {ital M}{sub {ital H}} dependence. The top-quark mass is predicted to be 124{sub {minus}34{minus}15}{sup +28+20} GeV, where the second uncertainty is from {ital M}{sub {ital H}}, with {ital m}{sub {ital t}}{lt}174 (182) GeV at 90 (95)% C.L. For the first time subleading effects and vertex corrections allow a significant separation of {ital m}{sub {ital t}} and {rho}{sub 0} in models with a nonminimal Higgs structure. Allowing arbitrary {ital m}{sub {ital t}} and Higgs representations one obtains sin{sup 2}{cflx {theta}}{sub {ital W}}({ital M}{sub {ital Z}})=0.2333{plus minus}0.0008, {rho}{sub 0}=0.992{plus minus}0.011, and {ital m}{sub {ital t}}{lt}294 (310) GeV. The implications of these results for ordinary and supersymmetric grand unified theories are considered. Supersymmetric theories with a grand desert between the supersymmetry and unification scales are in striking agreement with data for {ital M}{sub SUSY} in the {ital M}{sub {ital Z}--}1 TeV range. Ordinary grand unified theories breaking to the standard model in more than one step are also discussed.

• DOE Contract Number: AC02-76ER03071
• OSTI ID: 5451276
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 44:3; ISSN PRVDA; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

645203* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
CURRENTS
ELEMENTARY PARTICLES
LIE GROUPS
MASS
MATHEMATICAL MODELS
NEUTRAL CURRENTS
PARTICLE MODELS
POSTULATED PARTICLES
STANDARD MODEL
SU GROUPS
SUPERSYMMETRY
SYMMETRY
SYMMETRY GROUPS
TOP PARTICLES
U GROUPS
U-1 GROUPS
UNIFIED GAUGE MODELS
WEINBERG ANGLE