skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: b{r_arrow}s{gamma} constraints on the minimal supergravity model with large tan{beta}

Abstract

In the minimal supergravity model (MSUGRA), as the parameter tan{beta} increases, the charged Higgs boson and light bottom squark masses decrease, which can potentially increase contributions from tH{sup {plus_minus}}, {tilde g}{tilde b}{sub j} and {tilde Z}{sub i}{tilde b}{sub j} loops in the decay b{r_arrow}s{gamma}. We update a previous QCD improved b{r_arrow}s{gamma} decay calculation to include in addition the effects of gluino and neutralino loops. We find that, in the MSUGRA model, loops involving charginos also increase, and dominate over tW, tH{sup {plus_minus}}, {tilde g}{tilde q} and {tilde Z}{sub i}{tilde q} contributions for tan{beta}{approx_gt}5{minus}10. We find for large values of tan{beta}{approximately}35 that most of the parameter space of the MSUGRA model for {mu}{lt}0 is ruled out due to too large a value of branching ratio B(b{r_arrow}s{gamma}). For {mu}{gt}0 and large tan{beta}, most of parameter space is allowed, although the regions with the least fine-tuning (low m{sub 0} and m{sub 1/2}) are ruled out due to too {ital low} a value of B(b{r_arrow}s{gamma}). We compare the constraints from b{r_arrow}s{gamma} to constraints from the neutralino relic density, and to expectations for sparticle discovery at CERN LEP2 and the Fermilab Tevatron p{bar p} colliders. Finally, we show that non-universal GUT scale soft breaking squarkmore » mass terms can enhance gluino loop contributions to b{r_arrow}s{gamma} decay rate even if these are diagonal. {copyright} {ital 1998} {ital The American Physical Society}« less

Authors:
 [1];  [2];  [3];  [4]
  1. Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States)
  2. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
  3. Saint Leo College, St. Leo, Florida 33574 (United States)
  4. Department of Physics and Astronomy, University of Hawaii, Honolulu, Hawaii 96822 (United States)
Publication Date:
OSTI Identifier:
656285
Resource Type:
Journal Article
Journal Name:
Physical Review, D
Additional Journal Information:
Journal Volume: 58; Journal Issue: 1; Other Information: PBD: Jul 1998
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; B QUARKS; GAMMA DECAY; SUPERGRAVITY; HIGGS BOSONS; MASS; QUANTUM CHROMODYNAMICS; GLUONS; NEUTRAL PARTICLES; SPARTICLES; S QUARKS; GRAND UNIFIED THEORY

Citation Formats

Baer, H, Brhlik, M, Castano, D, and Tata, X. b{r_arrow}s{gamma} constraints on the minimal supergravity model with large tan{beta}. United States: N. p., 1998. Web. doi:10.1103/PhysRevD.58.015007.
Baer, H, Brhlik, M, Castano, D, & Tata, X. b{r_arrow}s{gamma} constraints on the minimal supergravity model with large tan{beta}. United States. doi:10.1103/PhysRevD.58.015007.
Baer, H, Brhlik, M, Castano, D, and Tata, X. Wed . "b{r_arrow}s{gamma} constraints on the minimal supergravity model with large tan{beta}". United States. doi:10.1103/PhysRevD.58.015007.
@article{osti_656285,
title = {b{r_arrow}s{gamma} constraints on the minimal supergravity model with large tan{beta}},
author = {Baer, H and Brhlik, M and Castano, D and Tata, X},
abstractNote = {In the minimal supergravity model (MSUGRA), as the parameter tan{beta} increases, the charged Higgs boson and light bottom squark masses decrease, which can potentially increase contributions from tH{sup {plus_minus}}, {tilde g}{tilde b}{sub j} and {tilde Z}{sub i}{tilde b}{sub j} loops in the decay b{r_arrow}s{gamma}. We update a previous QCD improved b{r_arrow}s{gamma} decay calculation to include in addition the effects of gluino and neutralino loops. We find that, in the MSUGRA model, loops involving charginos also increase, and dominate over tW, tH{sup {plus_minus}}, {tilde g}{tilde q} and {tilde Z}{sub i}{tilde q} contributions for tan{beta}{approx_gt}5{minus}10. We find for large values of tan{beta}{approximately}35 that most of the parameter space of the MSUGRA model for {mu}{lt}0 is ruled out due to too large a value of branching ratio B(b{r_arrow}s{gamma}). For {mu}{gt}0 and large tan{beta}, most of parameter space is allowed, although the regions with the least fine-tuning (low m{sub 0} and m{sub 1/2}) are ruled out due to too {ital low} a value of B(b{r_arrow}s{gamma}). We compare the constraints from b{r_arrow}s{gamma} to constraints from the neutralino relic density, and to expectations for sparticle discovery at CERN LEP2 and the Fermilab Tevatron p{bar p} colliders. Finally, we show that non-universal GUT scale soft breaking squark mass terms can enhance gluino loop contributions to b{r_arrow}s{gamma} decay rate even if these are diagonal. {copyright} {ital 1998} {ital The American Physical Society}},
doi = {10.1103/PhysRevD.58.015007},
journal = {Physical Review, D},
number = 1,
volume = 58,
place = {United States},
year = {1998},
month = {7}
}