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), Vol. 44:3; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

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