We examine Sommerfeld enhancement in dark matter annihilation as a potential origin of the halo-like gamma-ray excess near E ~ 20 GeV reported by Totani. A minimal model with a light CP-even scalar mediator naturally produces a velocity-dependent annihilation cross section consistent with thermal freeze-out, the Milky Way excess, and limits from dwarf spheroidal galaxies. We discuss future...
We investigate a cogenesis scenario for composite asymmetric dark matter framework: a dark sector has a similar strong dynamics to quantum chromodynamics in the standard model, and the dark-sector counterpart of baryons is the dark matter candidate. The Hawking evaporation of primordial black holes plays the role of a source of heavy scalar particles whose CP-violating decay into quarks and...
We explore the potential of future lepton colliders to shed light on the reheating era through the detection of dark matter (DM) that undergoes freeze-out during this phase of the Universe. In this framework, DM interacts with the Standard Model (SM) primarily via leptophilic effective operators, exhibiting highly suppressed couplings to quarks and gluons, consistent with the null results from...
