First LHC Constraints on Neutralinos

TL;DR

This paper explores how recent Higgs-like particle observations at the LHC constrain the properties of neutralinos in supersymmetric models, focusing on Higgs decay channels and their compatibility with experimental data.

Contribution

It provides the first LHC-based constraints on neutralino parameters, analyzing Higgs decay implications for supersymmetric models with specific parameter regions.

Findings

Large invisible Higgs decay branching ratios are disfavored by data.

Most of the parameter space with mu < 170 GeV and M_1 < 70 GeV at tan beta ~ 10 is excluded.

Parameter regions with mu < 120 GeV and M_1 < 70 GeV at tan beta ~ 40 are also constrained.

Abstract

The ATLAS and CMS collaborations have recently reported tantalizing hints of the existence of a 125 GeV Higgs--like particle, whose couplings appear to match well the Standard Model (SM) expectations. In this work, we study implications of this observation for the neutralino sector of supersymmetric models, assuming that the Higgs signal gets confirmed. In general, the Higgs decay into neutralinos can be one of its dominant decay channels. Since a large invisible Higgs decay branching ratio would be in conflict with the data, this possibility is now constrained. In particular, we find that most of the region mu < 170 GeV, M_1 < 70 GeV at tan beta ~ 10 and mu < 120 GeV, M_1 < 70 GeV at tan beta ~ 40 is disfavored.