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

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 ($\ddot{I}{€}_D$), 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 $m_{\mathrm{DM}}\sim \mathcal{O}(10\mathrm{TeV})$, dark meson masses $m_{\ddot{I}{€}_D}\sim 400\mathrm{GeV}$, $\ddot{I}{€}_D$ dominantly decaying to $t\bar{t}$, and a SUEP temperature $T_{\mathrm{SUEP}}\simeq 0.1m_{\ddot{I}€D}$, 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.

20 pages and 10 figures. Comments are welcome