WIMP Dark Matter in the U$\mu \nu$SSM

TL;DR

This paper explores a supersymmetric model extension called UμνSSM, which naturally includes a stable WIMP dark matter candidate, and analyzes its relic density and detection prospects considering collider and experimental constraints.

Contribution

It introduces a novel UμνSSM model with a built-in stable WIMP dark matter candidate and evaluates its relic density and detection signals within current experimental bounds.

Findings

The singlet fermion can account for the observed dark matter relic density.

Large parameter regions are accessible to upcoming direct detection experiments.

Constraints from LHC Z' searches significantly shape the viable parameter space.

Abstract

The U$\mu\nu$SSM is a $U(1)'$ extension of the $\mu\nu$SSM supersymmetric model, where baryon-number-violating operators as well as explicit mass terms are forbidden, and the potential domain wall problem is avoided. The gauge anomaly-cancellation conditions impose the presence of exotic quark superfields in the spectrum of U$\mu\nu$SSM models, and allow the presence of several singlet superfields under the standard model gauge group, in addition to the right-handed neutrino superfields. The gauge structure implies an additional discrete $Z_2$ symmetry in the superpotential, ensuring the stability of a singlet which behaves as WIMP dark matter without invoking $R$-parity. We analyze this novel possibility in detail, using the fermionic component of the singlet as the dark matter candidate. In particular, we compute its amount of relic density via $Z'$, Higgs-right sneutrino and dark matter mediated annihilations, and its potential signals in dark matter direct detection experiments. The constraints on the parameter space due to $Z'$ direct searches at the LHC are imposed in the analysis, as well as those from the hadronization inside the detector of the exotic quarks. Large regions of the parameter space turn out to be in the reach of the upcoming Darwin experiment.