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Title: {ital R}{sub {ital b}} in supersymmetric models

Abstract

We compute the supersymmetric contribution to {ital R}{sub {ital b}}{equivalent_to}{Gamma}({ital Z}{r_arrow}{ital b{bar b}})/{Gamma}({ital Z}{r_arrow} hadrons) in a variety of supersymmetric models. In the context of supergravity models with universal soft supersymmetry breaking and radiative electroweak breaking we find {ital R}{sub {ital b}}{sup SUSY}{approx_lt}0.0004, which does not shift significantly the standard model prediction ({ital R}{sub {ital b}}{sup SM}=0.2157 for {ital m}{sub {ital t}}=175 GeV; {ital R}{sub {ital b}}{sup expt}=0.2204{plus_minus}0.0020). We also compute {ital R}{sub {ital b}} in the minimal supersymmetric standard model (MSSM), and delineate the region of parameter space which yields interestingly large values of {ital R}{sub {ital b}}. This region entails light charginos and top squarks, but is {ital strongly} restricted by the {ital combined} constraints from {ital B}({ital b}{r_arrow}{ital s}{gamma}) and a not-too-large invisible top-quark branching ratio: only a few percent of the points with {ital R}{sub {ital b}}{sup SUSY}{gt}0.0020 (1{sigma}) are allowed.

Authors:
;  [1];  [1]
  1. Center for Theoretical Physics, Department of Physics, Texas A&M University, College Station, Texas 77843-4242 (United States)
Publication Date:
Research Org.:
Texas A&M Research Foundation
OSTI Identifier:
249543
DOE Contract Number:  
FG05-91ER40633
Resource Type:
Journal Article
Journal Name:
Physical Review, D
Additional Journal Information:
Journal Volume: 52; Journal Issue: 7; Other Information: PBD: 1 Oct 1995
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; SUPERSYMMETRY; Z NEUTRAL BOSONS; WEAK HADRONIC DECAY; SUPERGRAVITY; STANDARD MODEL; SYMMETRY BREAKING; BOTTOMONIUM; HADRONS

Citation Formats

Wang, X, Lopez, J L, Astroparticle Physics Group, Houston Advanced Research Center, Nanopoulos, D V, Astroparticle Physics Group, Houston Advanced Research Center, and CERN Theory Division, 1211 Geneva 23. {ital R}{sub {ital b}} in supersymmetric models. United States: N. p., 1995. Web. doi:10.1103/PhysRevD.52.4116.
Wang, X, Lopez, J L, Astroparticle Physics Group, Houston Advanced Research Center, Nanopoulos, D V, Astroparticle Physics Group, Houston Advanced Research Center, & CERN Theory Division, 1211 Geneva 23. {ital R}{sub {ital b}} in supersymmetric models. United States. https://doi.org/10.1103/PhysRevD.52.4116
Wang, X, Lopez, J L, Astroparticle Physics Group, Houston Advanced Research Center, Nanopoulos, D V, Astroparticle Physics Group, Houston Advanced Research Center, and CERN Theory Division, 1211 Geneva 23. Sun . "{ital R}{sub {ital b}} in supersymmetric models". United States. https://doi.org/10.1103/PhysRevD.52.4116.
@article{osti_249543,
title = {{ital R}{sub {ital b}} in supersymmetric models},
author = {Wang, X and Lopez, J L and Astroparticle Physics Group, Houston Advanced Research Center and Nanopoulos, D V and Astroparticle Physics Group, Houston Advanced Research Center and CERN Theory Division, 1211 Geneva 23},
abstractNote = {We compute the supersymmetric contribution to {ital R}{sub {ital b}}{equivalent_to}{Gamma}({ital Z}{r_arrow}{ital b{bar b}})/{Gamma}({ital Z}{r_arrow} hadrons) in a variety of supersymmetric models. In the context of supergravity models with universal soft supersymmetry breaking and radiative electroweak breaking we find {ital R}{sub {ital b}}{sup SUSY}{approx_lt}0.0004, which does not shift significantly the standard model prediction ({ital R}{sub {ital b}}{sup SM}=0.2157 for {ital m}{sub {ital t}}=175 GeV; {ital R}{sub {ital b}}{sup expt}=0.2204{plus_minus}0.0020). We also compute {ital R}{sub {ital b}} in the minimal supersymmetric standard model (MSSM), and delineate the region of parameter space which yields interestingly large values of {ital R}{sub {ital b}}. This region entails light charginos and top squarks, but is {ital strongly} restricted by the {ital combined} constraints from {ital B}({ital b}{r_arrow}{ital s}{gamma}) and a not-too-large invisible top-quark branching ratio: only a few percent of the points with {ital R}{sub {ital b}}{sup SUSY}{gt}0.0020 (1{sigma}) are allowed.},
doi = {10.1103/PhysRevD.52.4116},
url = {https://www.osti.gov/biblio/249543}, journal = {Physical Review, D},
number = 7,
volume = 52,
place = {United States},
year = {1995},
month = {10}
}