Search

We introduce a model for matter genesis in which both the baryonic and dark matter asymmetries originate from a first-order phase transition in a dark sector with an SU(3)×SU(2)×U(1) gauge group and minimal matter content. In the simplest scenario, we predict that dark matter is a dark antineutron with mass of either mn¯=1.36 GeV or mn¯=1.63 GeV. Alternatively, dark matter may be comprised of equal numbers of dark antiprotons and pions. In either scenario, this model is highly discoverable through both dark matter direct detection and dark photon search experiments. The strong dark matter self-interactions may ameliorate small-scale structure problems, while the strongly first-order phase transition may be confirmed at future gravitational wave observatories.

It is often said that asymmetric dark matter is light compared to typical weakly interacting massive particles. Here we point out a simple scheme with a neutrino portal and O(60 GeV) asymmetric dark matter which may be "added"to any standard electroweak baryogenesis scenario. The dark sector contains a copy of the Standard Model gauge group, as well as one matter family (at least), Higgs, and right-handed neutrino. After baryogenesis, some lepton asymmetry is transferred to the dark sector through the neutrino portal where dark sphalerons convert it into a dark baryon asymmetry. Dark hadrons form asymmetric dark matter and may be directly detected due to the vector portal. Surprisingly, even dark anti-neutrons may be directly detected if they have a sizeable electric dipole moment. The dark photons visibly decay in current and future experiments which probe complementary parameter space to dark matter direct detection searches. Exotic Higgs decays are excellent signals at future e+e- Higgs factories.

A recent cosmological bound on the gravitino mass, m3/2

Dark matter could be a thermal relic comprised of strongly interacting massive particles (SIMPs), where 3→2 interactions set the relic abundance. Such interactions generically arise in theories of chiral symmetry breaking via the Wess-Zumino-Witten term. In this work, we show that an axionlike particle can successfully maintain kinetic equilibrium between the dark matter and the visible sector, allowing the requisite entropy transfer that is crucial for SIMPs to be a cold dark matter candidate. Constraints on this scenario arise from beam dump and collider experiments, from the cosmic microwave background, and from supernovae. We find a viable parameter space when the axionlike particle is close in mass to the SIMP dark matter, with strong-scale masses of order a few hundred MeV. Many planned experiments are set to probe the parameter space in the near future.