Conveners
DM IV
- Robert McGehee (University of California, Berkeley)
In this talk, we analyze the viability of dark matter candidates arising from a secluded, confining, large-N SU(N) gauge theory with a single quark flavor. In a SU(N) gauge theory with a single quark flavor, the low-energy bound states consist of a delta-like baryon and an eta-prime meson. By solving coupled Boltzmann equations, we demonstrate that there are ample regions of parameter space in...
We study the complete history of structure formation of a simple dark sector and show how to form exotic compact objects that vary in size from a few to millions of solar masses. These exotic compact objects may be detected and their properties measured at new high-precision astronomical observatories, giving insight into the particle nature of the dark sector without the requirement of...
We consider a U(1)_X gauge symmetry extension of the Standard Model (SM) with a Z′-portal Majorana fermion dark matter that allows for a relatively light gauge boson Z′ with mass of 10 MeV− a few GeV and a much heavier dark matter through the freeze-in mechanism. In a second scenario the roles are reversed, and the dark matter mass, in the keV range or so, lies well below the Z′ mass, say, ∼1...
We study a simplified freeze-in dark matter model with a dark matter $\chi$ and a light scalar mediator $\phi$ which couples only to neutrinos in the Standard Model. We point out two possible UV origins generating extremely small scalar and pseudo-scalar couplings between $\phi$ and neutrinos. We find benchmarks to realize the correct relic density with and without re-annihilation scheme by...
The freeze-in production of FIMP dark matter candidate through neutrino portal is discussed. The hidden sector is comprised of a fermion and a scalar, while a heavy right handed neutrino is responsible for mediating the interaction between SM and hidden sectors. In addition, we assume that an early matter-dominated era took place for some period between inflation and BBN, making the Universe...
I will present a new mechanism for thermally produced dark matter, based on a semi-annihilation-like process, χ + χ + SM → χ + SM, with intriguing consequences for the properties of dark matter. First, its mass is low, 1 GeV (but 5 keV to avoid structure-formation constraints). Second, it is strongly interacting, leading to kinetic equilibrium between the dark and visible sectors, avoiding...
In the conventional weakly-interacting massive particle (WIMP) paradigm the late-time density of dark matter (DM) is set by the rate of two-body annihilations, but there has been considerable recent interest in exploring alternative DM scenarios where other interactions control the final abundance. I will show that by fully exploring the parameter space of a simple, weakly-coupled dark sector,...
Neutron stars serve as excellent next-generation thermal detectors of dark matter, heated by the scattering and annihilation of dark matter accelerated to relativistic speeds in their deep gravitational wells. However, the dynamics of neutron star cores are uncertain, making it difficult at present to unequivocally compute dark matter scattering in this region. On the other hand, the physics...
