Enhanced Cosmic-Ray Antinuclei Fluxes with Dark Matter Annihilation into SUEPs

TL;DR

This paper proposes that dark matter annihilations into a confining dark sector producing SUEPs can significantly enhance cosmic-ray antinuclei fluxes, potentially explaining signals detected by AMS-02 and GAPS.

Contribution

It introduces a novel mechanism where dark matter annihilates into SUEPs, leading to increased antinuclei production, contrasting with standard predictions.

Findings

Dark matter annihilation into SUEPs can produce detectable antinuclei fluxes.

Predicted antinuclei signals could be observed by AMS-02 and GAPS experiments.

The model constrains dark sector parameters based on potential future detections.

Abstract

Standard-Model (SM) hadronic parton showers initiated by secondary cosmic-ray production or dark matter (DM) annihilations robustly predict very low antinuclei yields and a strong additional suppression for heavier antinuclei. We show that an important exception can arise if DM annihilates into a confining dark sector that produces Soft Unclustered Energy Patterns (SUEPs). The hallmark of SUEPs is the emission of very large multiplicities of soft dark mesons ($\pi_D$), which can overcome the usual phase-space suppression of antinuclei formation in parton showers, provided that the dark mesons decay promptly into SM quarks, i.e. within a SM hadronization length. We study several benchmark realizations and find that for DM masses $m_{\rm DM}\sim\mathcal{O}(10~\mathrm{TeV})$, dark meson masses $m_{\pi_D} \sim 400~\mathrm{GeV}$, $\pi_D$ dominantly decaying to $t\bar t$, and a SUEP temperature $T_{\rm SUEP}\simeq 0.1\,m_{\pi D}$, DM annihilation into SUEPs can yield tens of antideuterons and a few antihelium--3 events at AMS-02 at kinetic energies of $\mathcal{O}(\mathrm{GeV}$/n) and a few antideuterons and antihelium-3 events in GAPS at energies below 0.5 GeV/n. A future confirmation of an antinuclei signal by the AMS-02 or GAPS experiments could provide hints for hidden confining dynamics and would significantly constrain the relevant SUEP parameters.