Discovering Asymmetric Dark Matter with Anti-Neutrinos

TL;DR

This paper explores how asymmetric dark matter could be detected via neutrino signals from dark matter decays, emphasizing the role of the neutrino portal operator and current experimental bounds.

Contribution

It identifies the neutrino portal as a key decay channel for ADM and derives bounds on decay operators up to dimension 6, linking particle physics to neutrino observations.

Findings

Decays to neutrinos are the strongest constraints for ADM models.

Current bounds require the suppression scale of decay operators to be >~ 10^12 GeV.

Detection of neutrino signals could confirm ADM presence.

Abstract

We discuss possible signatures of Asymmetric Dark Matter (ADM) through dark matter decays to neutrinos. We specifically focus on scenarios in which the Standard Model (SM) baryon asymmetry is transferred to the dark sector (DS) through higher dimensional operators in chemical equilibrium. In such cases, the dark matter (DM) carries lepton and/or baryon number, and we point out that for a wide range of quantum number assignments, by far the strongest constraints on dark matter decays come from decays to neutrinos through the "neutrino portal" operator HL. Together with the facts that ADM favors lighter DM masses ~ a few GeV and that the decays would lead only to anti-neutrinos and no neutrinos (or vice versa), the detection of such decays at neutrino telescopes would provide compelling evidence for ADM. We discuss current and future bounds on models where the DM decays to neutrinos through operators of dimension <= 6. For dimension 6 operators, the scale suppressing the decay is bounded to be >~ 10^12 - 10^13 GeV.