A non-zero topological angle in a confining dark sector induces CP-violating pion-baryon couplings that naturally generate velocity-dependent dark matter self-interactions and dark electric dipole moments for direct detection.
Split SIMPs with Decays
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
We discuss a minimal realization of the strongly interacting massive particle (SIMP) framework. The model includes a dark copy of QCD with three colors and three light flavors. A massive dark photon, kinetically mixed with the Standard Model hypercharge, maintains kinetic equilibrium between the dark and visible sectors. One of the dark mesons is necessarily unstable but long-lived, with potential impact on CMB observables. We show that an approximate "isospin" symmetry acting on the down-type quarks is an essential ingredient of the model. This symmetry stabilizes the dark matter and allows to split sufficiently the masses of the other states to suppress strongly their relic abundances. We discuss for the first time the SIMP cosmology with sizable mass splittings between all meson multiplets. We demonstrate that the SIMP mechanism remains efficient in setting the dark matter relic density, while CMB constraints on unstable relics can be robustly avoided. We also consider the phenomenological consequences of isospin breaking, including dark matter decay. Cosmological, astrophysical, and terrestrial probes are combined into a global picture of the parameter space. In addition, we outline an ultraviolet completion in the context of neutral naturalness, where confinement at the GeV scale is generic. We emphasize the general applicability of several novel features of the SIMP mechanism that we discuss here.
citation-role summary
citation-polarity summary
fields
hep-ph 3years
2026 3roles
background 1polarities
background 1representative citing papers
Dark pions stabilized by U(1) flavor symmetry in an SU(3)/SO(3) dark sector obtain the correct thermal relic density through up-scatterings to heavier mesons and dark eta decays, producing LHC signals from long-lived particle showers.
A minimal electrophilic ALP portal for SIMP pion dark matter widens the allowed parameter space, making an ALP mass of order 10 MeV viable and consistent with the X17 anomaly.
citing papers explorer
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Dark Neutrons as Dark Matter: Collisions in Halos and Direct Detection from Dark CP Violation
A non-zero topological angle in a confining dark sector induces CP-violating pion-baryon couplings that naturally generate velocity-dependent dark matter self-interactions and dark electric dipole moments for direct detection.
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Dark Matter on a Slide
Dark pions stabilized by U(1) flavor symmetry in an SU(3)/SO(3) dark sector obtain the correct thermal relic density through up-scatterings to heavier mesons and dark eta decays, producing LHC signals from long-lived particle showers.
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Axion-Like Electrophilic Portal for Pion Dark Matter
A minimal electrophilic ALP portal for SIMP pion dark matter widens the allowed parameter space, making an ALP mass of order 10 MeV viable and consistent with the X17 anomaly.