Constraints on the minimal supergravity model from the $b \to s\gamma$ decay

Wu, Ji-zhi; Nath, Pran; Arnowitt, Richard L.

doi:10.1103/PhysRevD.51.1371

Article
Report number	hep-ph/9406346 ; CTP-TAMU-03-94 ; NUB-TH-7316-94 ; CERN-TH-3092-94 ; CTP-TAMU-03-94 ; NUB-TH-7316-94-[SIC!] ; CERN-TH-3092-94-[SIC!] ; NUB-TH-3092-94 ; CERN-TH-7316-94
Title	Constraints on the minimal supergravity model from the $b \to s\gamma$ decay
Author(s)	Wu, Ji-zhi (Texas A-M) ; Arnowitt, Richard L. (Texas A-M) ; Nath, Pran (CERN ; Northeastern U.)
Publication	1995
Imprint	1994
Number of pages	18
In:	Phys. Rev. D 51 (1995) 1371-1376
DOI	10.1103/PhysRevD.51.1371
Subject category	Particle Physics - Phenomenology
Abstract	The constraints on the minimal supergravity model from the b->s+\gamma decay are studied. A large domain in the parameter space for the model satisfies the CLEO bound, BR(b->s+\gamma)<5.4X10 {-4}. However, the allowed domain is expected to diminish significantly with an improved bound on this decay. The dependence of the b->s+\gamma branching ratio on various parameters is studied in detail. It is found that, for A_t<0 and the top quark mass within the vicinity of the center of the CDF value, m_t {pole}=174\pm17 GeV, there exists only a small allowed domain because the light stop is tachyonic for most of the parameter space. A similar phenomenon exists for a lighter top and A_t negative when the GUT coupling constant is slightly reduced. For A_t>0, however, the branching ratio is much less sensitive to small changes in m_t, and \alpha_G.