Abstract We consider a new mechanism for enhancing the self-scattering and annihilation cross sections for dark matter with multiple components but without a light mediator. The lighter dark matter component plays a role of the u-channel pole in the elastic co-scattering for dark matter. leading to a large self-scattering cross section and a Sommerfeld enhancement for semi-annihilatio... https://foldlyers.shop/product-category/phone-wallplates/