A multi-component SIMP model with U(1)X → Z2 x Z3

Multi-component dark matter scenarios are studied in the model with U(1)(X) dark gauge symmetry that is broken into its product subgroup Z(2) x Z(3) a la Krauss-Wilczek mechanism. In this setup, there exist two types of dark matter fields, X and Y, distinguished by different Z(2) x Z(3) charges. The real and imaginary parts of the Z(2)-charged field, X-R and X-I, get different masses from the U(1)(X) symmetry breaking. The field Y, which is another dark matter candidate due to the unbroken Z(3) symmetry, belongs to the Strongly Interacting Massive Particle (SIMP)-type dark matter. Both X-I and X-R may contribute to Y's 3 -> 2 annihilation processes, opening a new class of SIMP models with a local dark gauge symmetry. Depending on the mass difference between X-I and X-R, we have either two-component or three-component dark matter scenarios. In particular two- or three-component SIMP scenarios can be realised not only for small mass difference between X and Y, but also for large mass hierarchy between them, which is a new and unique feature of the present model. We consider both theoretical and experimental constraints, and present four case studies of the multi-component dark matter scenarios.