Probing supergravity models with the b→ sγ microscope

الأصل · EN

We present a calculation of the branching ratio in two well motivated supersymmetric models: the minimal SU(5) and the no-scale flipped SU(5) supergravity models. We find that the improved CLEO upper bound (<5.4×10⁻⁴ at 95% CL) does not yet constrain the minimal SU(5) supergravity model, where =(2.3-3.6)×10⁻⁴. In the flipped SU(5) model the CLEO bound is constraining, although still not very significantly, even for light charged Higgs masses. An improvement in sensitivity by a factor of two will probe all (more than half) of the parameter space of the minimal (flipped) SU(5) supergravity model. This ``resolution" of the microscope far surpasses that of present collider experiments. In the flipped model there exists a significant region of parameter space where is highly suppressed due to a new phenomenon involving a complicated cancellation against the QCD correction parameter.