Axion-like particle assisted strongly interacting massive particle

Abstract

We propose a new realization of strongly interacting massive particles (SIMP) as self-interacting dark matter, where SIMPs couple to the Standard Model sector through an axion-like particle. Our model gets over major obstacles accompanying the original SIMP model, such as a missing mechanism of kinetically equilibrating SIMPs with the SM plasma as well as marginal perturbativity of the chiral Lagrangian density. Remarkably, the parameter region realizing ${\sigma }_{\mathrm{self}}/m_{\mathrm{DM}}\simeq 0.1\text{–}1{\mathrm{cm}}^2/\mathrm{g}$ is within the reach of future beam dump experiments such as the Search for Hidden Particles (SHiP) experiment.

Comments: 11 pages, 1 figure. v2: figure updated, discussions improved