[epsilon][sub [ital b]] constraints on the minimal SU(5) and SU(5)[times]U(1) supergravity models

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.50.R6686· OSTI ID:7097926

Kim, J E ^[1]; Park, G T ^[2]

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1. Center for Theoretical Physics and Department of Physics, Seoul National University, Seoul, 151-742 (Korea, Republic of)
2. Center for Theoretical Physics, Seoul National University, Seoul, 151-742 (Korea, Republic of)

We have performed a systematic analysis to compute the one-loop electroweak corrections to the [ital Z][r arrow][ital b[bar b]] vertex in terms of [epsilon][sub [ital b]] and [ital R][sub [ital b]] in the context of the minimal SU(5) and no-scale SU(5)[times]U(1) supergravity models. With the measured top mass, [ital m][sub [ital t]]=174[plus minus]10[sub [minus]12][sup +13] GeV, recently announced by CDF, we use the latest CERN LEP data on [epsilon][sub [ital b]] and [ital R][sub [ital b]] [[equivalent to][Gamma]([ital Z][r arrow][ital b[bar b]])/[Gamma]([ital Z][r arrow]hadrons)] in order to constrain further the two models. We find that the present LEP data on [epsilon][sub [ital b]] and [ital R][sub [ital b]] constrain the two models rather severely. Especially the low-tan[beta] region is constrained more severely. tan[beta][approx lt]2.5 (4.0) is excluded by [epsilon][sub [ital b]] at 90% C.L. for [ital m][sub [ital t]][approx gt]170 [180] GeV in the minimal SU(5) [no-scale SU(5)[times]U(1)] supergravity. An even more stringent constraint comes from [ital R][sub [ital b]]. It excludes tan[beta][approx lt]4.0 at 90% C.L. for [ital m][sub [ital t]][approx gt]160 [170] GeV in the minimal SU(5) [no-scale SU(5)[times]U(1)] supergravity. We also find that the sign on [mu] in the two models can be determined from [epsilon][sub [ital b]] and [ital R][sub [ital b]] at 90% C.L.

• OSTI ID: 7097926
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 50:11; ISSN 0556-2821; ISSN PRVDAQ
• Country of Publication: United States
• Language: English

Related Subjects

662210* -- Specific Theories & Interaction Models
662380 -- Decays of Intermediate Bosons-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOSONS
BOTTOMONIUM
CONSTRAINTS
CORRECTIONS
DECAY
ELEMENTARY PARTICLES
FIELD THEORIES
HADRONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
LIE GROUPS
MASS
MESONS
PARTICLE DECAY
POSTULATED PARTICLES
Pa
Particle Systematics-- Unified Theories & Models-- (1992-)
QUARKONIUM
SU GROUPS
SU-5 GROUPS
SUPERGRAVITY
SYMMETRY GROUPS
TOP PARTICLES
U GROUPS
U-1 GROUPS
UNIFIED-FIELD THEORIES
Z NEUTRAL BOSONS