Indirect Searches of the Degenerate MSSM

TL;DR

This paper explores a degenerate MSSM scenario where nearly equal soft mass terms allow for a light supersymmetric spectrum compatible with current experimental constraints and the muon anomalous magnetic moment.

Contribution

It introduces a nearly degenerate soft term scenario in MSSM that remains consistent with Higgs, B-physics, and dark matter constraints, and highlights its testability with upcoming direct detection experiments.

Findings

Supersymmetric particles as light as 600 GeV are viable.

The scenario can explain the muon g-2 anomaly within 2σ.

XENONnT will test this degenerate MSSM framework.

Abstract

A degenerate sfermionic particle spectrum can escape constraints from flavor physics, and at the same time evade the limits from the direct searches if the degeneracy extends to the gaugino-higgsino sector. Inspired by this, we consider a scenario where all the soft terms have an approximately common mass scale at $M_{\text{SUSY}}$, with splittings $\lesssim \mathcal{O}(10\%)$. As a result, the third generation sfermions have large to maximal (left-right) mixing, the same being the case with charginos and some sectors of the neutralino mass matrix. We study this scenario in the light of discovery of the Higgs boson with mass $\sim$ 125 GeV. We consider constraints from $B$-physics, the anomalous magnetic moment of the muon and the dark matter relic density. We find that a supersymmetric spectrum as light as 600 GeV could be consistent with all current data and also account for the observed anomalous magnetic moment of the muon within $2\sigma$. The neutralino relic density is generally too small to saturate the measured cold dark matter relic density. Direct detection limits from XENON100 and LUX put severe constraints on this scenario which will be conclusively probed by XENONnT experiment.