Constraints from the decay B_s -> mu mu and LHC limits on Supersymmetry

TL;DR

This paper examines how recent LHC limits on the decay B_s -> mu mu constrain Supersymmetry models, finding that these constraints are less restrictive than direct searches when considering relic density and Higgs limits.

Contribution

It demonstrates that the B_s -> mu mu decay limits do not significantly restrict the SUSY parameter space compared to direct searches and Higgs constraints, especially when relic density is considered.

Findings

B_s -> mu mu limits are less restrictive than direct searches.

Large tanbe regions are not excluded when considering relic density.

Negative interference regions can suppress B_s -> mu mu below SM expectations.

Abstract

The pure leptonic decay B_s -> mu mu is strongly suppressed in the Standard Model (SM), but can have large enhancements in Supersymmetry, especially at large values of tanbe. New limits on this decay channel from recent LHC data have been used to claim that these limits restrict the SUSY parameter space even more than the direct searches. However, direct searches are hardly dependent on tanbe, while BR(B_s -> mu mu) is proportional to tanbe^6. The relic density constraint requires large tanbe in a large region of the parameter space, which can lead to large values of B_s -> mu mu. Nevertheless, the experimental upper limit on BR(B_s -> mu mu) is not constraining the parameter space of the CMSSM more than the direct searches and the present Higgs limits, if combined with the relic density. We also observe SUSY parameter regions with negative interferences, where the B_s -> mu mu value is up to a factor three below the SM expectation, even at large values of tanbe.