We present a novel dark matter candidate, an Elastically Decoupling Relic (ELDER), which is a cold thermal relic whose present abundance is determined by the cross-section of its elastic scattering on Standard Model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross-section with electrons, photons and/or...
In this talk I will go over a new mechanism for setting the relic abundance of a thermal dark matter candidate. Unlike the usual WIMP paradigm, the abundance is set without chemical equilibrium between the Standard Model and the dark sector at freeze-out. The premise is to consider multiple degenerate particles in the dark sector, with a subset of those particles decaying to the visible...
In this talk, I will present a dark matter model in which both the dark sector and the visible sector share a common asymmetry. This asymmetry is mediated by an unstable dark particle of baryon number one through a semi-annihilation process. We realize a viable parameter space in which we find (1) the correct dark matter abundance, (2) the correct baryon asymmetry, and (3) a plausible dark...
Of the three notable exceptions to the standard calculation of dark matter freezeout, namely co-annihilation, resonant annihilation and forbidden annihilation, the third is the least explored in the literature. Here DM annihilates to states heavier than itself, therefore the thermal annihilation cross-section is set by averaging over the tail of its velocity distribution. (At zero temperature,...
Besides solving the hierarchy problem by introducing an SM-neutral twin sector (hidden naturalness), Twin Higgs models naturally furnish a WIMP-like dark matter (DM) scenario with an attractive DM candidate ${}-{}$ the lightest twin charged lepton. The twin particle spectrum contains light twin particles, including the twin-photon and neutrinos, that are customarily assumed to be either heavy...
Dynamical Dark Matter (DDM) is a new frame work for dark-matter physics that relies on a balancing between decay widths and abundances across a vast ensemble of particle species which collectively constitute the dark-matter candidate. Such a balancing can be achieved in broad variety of ways; however, only a small number of these possibilities have thus far been explored in the literature....
In non-minimal dark-matter models such as Dynamical Dark Matter (DDM), the mass spectrum of the dark-sector states plays a crucial role in dark-matter phenomenology. In this talk, I examine one natural method in which a particularly auspicious mass spectrum can be generated for an ensemble of such states via early-universe processes which are essentially random. Despite this inherent...
We demonstrate that multi-component scalar ensembles in the early universe can experience a variety of surprising phenomena when subject to a cosmological mass-generating phase transition. These include severe suppressions to their late-time cosmological (relic) abundance, parametrically resonant enhancements, re-distribution of energy density across the ensemble, and a ``re-overdamping''...
