Natural Supersymmetry and b -> s gamma constraints

TL;DR

This paper examines how the observed b -> s gamma decay rate constrains natural supersymmetry models, highlighting the unavoidable fine-tuning required due to these experimental limits.

Contribution

It analyzes the impact of b -> s gamma constraints on natural supersymmetry, emphasizing the unavoidable fine-tuning and specific parameter conditions.

Findings

5-10% fine-tuning is inevitable due to b -> s gamma constraints.

Light stops and higgsinos are essential for reducing fine-tuning.

Constraints depend on the messenger scale and gaugino mass relations.

Abstract

We investigate constraints from the observed branching ratio for b -> s gamma and fine-tuning in the framework of natural supersymmetry. The natural supersymmetry requires the large trilinear coupling of the stop sector, light higgsinos (a small mu parameter) and light stops, in order to reduce the fine-tuning in the Higgs sector while avoiding the LEP constraint. It is found that in such a scenario 5% (10%) level of fine-tuning is inevitable due to the b -> s gamma constraint even if the messenger scale is as low as 10^5 GeV (10^4 GeV), provided that the gaugino masses satisfy the GUT relation.