Hiding the little hierarchy problem in the NMSSM

TL;DR

This paper explores a specific pattern of supersymmetry breaking in the NMSSM that naturally reduces the hierarchy between the supersymmetry breaking scale and the electroweak scale, with phenomenological implications.

Contribution

It introduces a minimal set of soft terms at the GUT scale within the NMSSM, inspired by gaugino mediation and higher-dimensional models, and analyzes their low-energy phenomenology.

Findings

Light singlet scalar for low $mbda$

Singlino as LSP at low $mbda$

Gravitino as LSP for large $mbda$

Abstract

In this paper we consider a set of soft supersymmetry breaking terms within the NMSSM which leads to a small hierarchy between the supersymmetry breaking scale and the electroweak scale. Specifically only the gaugino masses and the soft term in the Higgs sector are non-vanishing at the GUT scale. This pattern can be found in gaugino mediated models and in higher-dimensional orbifold GUTs. We study the phenomenology of this scenario and find different low energy spectra depending on the Yukawa coupling $\lambda$ of the NMSSM singlet. In particular, for low values of $\lambda$ the singlet is the lightest scalar and the singlino is the LSP while for large values of $\lambda$ both are heavy and the gravitino can be the LSP. The singlet pseudoscalar is very light in the entire parameter space.