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Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2
A previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R_b. We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and the Tevatron, finding that a generic supersymmetric model can...
Autores principales: | , , |
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Lenguaje: | eng |
Publicado: |
1996
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Materias: | |
Acceso en línea: | https://dx.doi.org/10.1016/S0370-2693(97)00156-1 http://cds.cern.ch/record/317020 |
_version_ | 1780890422816538624 |
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author | Ellis, John R. Lopez, Jorge L. Nanopoulos, Dimitri V. |
author_facet | Ellis, John R. Lopez, Jorge L. Nanopoulos, Dimitri V. |
author_sort | Ellis, John R. |
collection | CERN |
description | A previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R_b. We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and the Tevatron, finding that a generic supersymmetric model cannot contribute more than about one-and-a-half current experimental standard deviations to R_b. We then specialize this analysis to minimal supergravity models with universal high-energy boundary conditions, and find a much more stringent upper bound R^{susy}_b < 0.0003. We discuss in detail why such models can only attain values of R^{susy}_b that are considerably smaller even than those obtainable in more general supersymmetric models. |
id | cern-317020 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 1996 |
record_format | invenio |
spelling | cern-3170202023-03-15T19:10:52Zdoi:10.1016/S0370-2693(97)00156-1http://cds.cern.ch/record/317020engEllis, John R.Lopez, Jorge L.Nanopoulos, Dimitri V.Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2Particle Physics - PhenomenologyA previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R_b. We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and the Tevatron, finding that a generic supersymmetric model cannot contribute more than about one-and-a-half current experimental standard deviations to R_b. We then specialize this analysis to minimal supergravity models with universal high-energy boundary conditions, and find a much more stringent upper bound R^{susy}_b < 0.0003. We discuss in detail why such models can only attain values of R^{susy}_b that are considerably smaller even than those obtainable in more general supersymmetric models.A previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R_b. We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and the Tevatron, finding that a generic supersymmetric model cannot contribute more than about one-and-a-half current experimental standard deviations to R_b. We then specialize this analysis to minimal supergravity models with universal high-energy boundary conditions, and find a much more stringent upper bound R~{susy}_b < 0.0003. We discuss in detail why such models can only attain values of R~{susy}_b that are considerably smaller even than those obtainable in more general supersymmetric models.A previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R b ≡ Γ(Z 0 → b b) Γ(Z 0 → hadrons ) . We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and the Tevatron, finding that a generic supersymmetric model cannot contribute more than about one-and-a-half current experimental standard deviations to R b . We then specialize this analysis to minimal supergravity models with universal high-energy boundary conditions, and find a much more stringent upper bound R b susy < 0.0003. We discuss in detail why such models can only attain values of R b susy that are considerably smaller than those obtainable in more general supersymmetric models.hep-ph/9612376CERN-TH-96-354DOE-ER-40717-37CTP-TAMU-64-96ACT-18-96ACT-1996-18CERN-TH-96-354CTP-TAMU-96-64DOE-ER-40717-37oai:cds.cern.ch:3170201996-12-16 |
spellingShingle | Particle Physics - Phenomenology Ellis, John R. Lopez, Jorge L. Nanopoulos, Dimitri V. Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2 |
title | Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2 |
title_full | Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2 |
title_fullStr | Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2 |
title_full_unstemmed | Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2 |
title_short | Supersymmetry, Supergravity and $R_b$ revisited in the light of LEP 2 |
title_sort | supersymmetry, supergravity and $r_b$ revisited in the light of lep 2 |
topic | Particle Physics - Phenomenology |
url | https://dx.doi.org/10.1016/S0370-2693(97)00156-1 http://cds.cern.ch/record/317020 |
work_keys_str_mv | AT ellisjohnr supersymmetrysupergravityandrbrevisitedinthelightoflep2 AT lopezjorgel supersymmetrysupergravityandrbrevisitedinthelightoflep2 AT nanopoulosdimitriv supersymmetrysupergravityandrbrevisitedinthelightoflep2 |