Sneutrino cold dark matter, a new analysis: relic abundance and detection rates

TL;DR

The paper reevaluates sneutrinos as cold dark matter candidates across STD MSSM and several neutrino-mass-motivated MSSM extensions, linking relic abundance and detection prospects to the neutrino mass sector. It performs comprehensive parameter-space scans to compute the relic density $\Omega h^{2}$, direct-detection cross sections with rescaling by $\xi$, and a suite of indirect signals (antiprotons, antideuterons, gamma rays) plus Earth-centered neutrinos, across standard, right-handed, and lepton-number-violating scenarios. The key findings are that STD MSSM sneutrinos are generally subdominant DM with strong direct-detection tension, LR models allow broad regions where sneutrinos can be dominant or subdominant DM with viable direct detection and promising indirect signals, and MAJ see-saw frameworks (especially with $M=1$ TeV) yield rich, testable phenomenology via multiple channels, while MAJ[B] with $M=10^9$ GeV is more constrained and typically subdominant. Neutrino-mass constraints and inelastic $Z$-couplings play pivotal roles in shaping the viable parameter space and guiding the complementary use of direct and indirect detection experiments.

Abstract

We perform a new and updated analysis of sneutrinos as dark matter candidates, in different classes of supersymmetric models. We extend previous analyses by studying sneutrino phenomenology for full variations of the supersymmetric parameters which define the various models. We first revisit the standard Minimal Supersymmetric Standard Model, concluding that sneutrinos are marginally compatible with existing experimental bounds, including direct detection, provided they compose a subdominant component of dark matter. We then study supersymmetric models with the inclusion of right-handed fields and lepton-number violating terms. Simple versions of the lepton-number-violating models do not lead to phenomenology different from the standard case when the neutrino mass bounds are properly included. On the contrary, models with right-handed fields are perfectly viable: they predict sneutrinos which are compatible with the current direct detection sensitivities, both as subdominant and dominant dark matter components. We also study the indirect detection signals for such successful models: predictions for antiproton, antideuteron and gamma-ray fluxes are provided and compared with existing and future experimental sensitivities. The neutrino flux from the center of the Earth is also analyzed.