Selectron NLSP in Gauge Mediation

TL;DR

This paper explores gauge mediation models with a selectron NLSP, detailing how such spectra can be realized, their collider signatures, and compatibility with a 126 GeV Higgs, including explicit models and LHC constraints.

Contribution

It provides a comprehensive characterization and explicit constructions of gauge mediation models with selectron NLSP, incorporating Higgs mass constraints and collider phenomenology.

Findings

Selectron NLSP spectra can be achieved without new flavor misalignment.

Explicit messenger models compatible with a 126 GeV Higgs are constructed.

Collider signatures include multilepton final states with prompt, displaced, or long-lived NLSP decays.

Abstract

We discuss gauge mediation models in which the smuon and the selectron are mass-degenerate co-NLSP, which we, for brevity, refer to as selectron NLSP. In these models, the stau, as well as the other superpartners, are parametrically heavier than the NLSP. We start by taking a bottom-up perspective and investigate the conditions under which selectron NLSP spectra can be realized in the MSSM. We then give a complete characterization of gauge mediation models realizing such spectra at low energies. The splitting between the slepton families is induced radiatively by the usual hierarchies in the Standard Model Yukawa couplings and hence, no new sources of flavour misalignment are introduced. We construct explicit weakly coupled messenger models which give rise to selectron NLSP, while accommodating a 126 GeV MSSM Higgs mass, both within the framework of General Gauge Mediation and in extensions where direct couplings between the messengers and the Higgs fields are present. In the latter class of models, large A-terms and relatively light stops can be achieved. The collider signatures of these models typically involve multilepton final states. We discuss the relevant LHC bounds and provide examples of models where the decay of the NLSP selectron is prompt, displaced or long-lived. The prompt case can be viewed as an ultraviolet completion of a simplified model recently considered by the CMS collaboration.