Present Status and Future Tests of the Higgsino-Singlino Sector in the NMSSM

TL;DR

This paper assesses the current experimental constraints and future prospects for detecting higgsino-singlino particles in the NMSSM, highlighting unexplored natural regions with lighter charginos.

Contribution

It provides a comprehensive analysis of the viable parameter space of the higgsino-singlino sector in the NMSSM under recent constraints and forecasts future LHC testability.

Findings

Current constraints do not exclude all natural regions with lighter charginos.

Run I LHC data does not rule out additional parameter space.

HL-LHC will probe some but not all remaining viable regions.

Abstract

The light higgsino-singlino scenario of the NMSSM allows to combine a naturally small $\mu$ parameter with a good dark matter relic density. Given the new constraints on spin-dependent and spin-independent direct detection cross sections in 2016 we study first which regions in the plane of chargino- and LSP-masses below 300 GeV remain viable. Subsequently we investigate the impact of searches for charginos and neutralinos at the LHC, and find that the limits from run I do not rule out any additional region in this plane. Only the HL-LHC at 3000 fb$^{-1}$ will test parts of this plane corresponding to higgsino-like charginos heavier than 150 GeV and relatively light singlinos, but notably the most natural regions with lighter charginos seem to remain unexplored.