Dr
Julia Harz
(LPTHE / ILP Paris)
26/09/2018, 16:30
Cosmology & Astroparticle Physics
Given the growing constraints on WIMP dark matter, coannihilation scenarios are gaining more and more interest. However, in order to theoretically predict the relic density with a certain precision for a specific model, different effects have to be taken into account. We introduce a so far neglected effect - Higgs enhancement - that significantly alters the prediction of the dark matter...
Mr
Jeff Dror
(Lawrence Berkeley National Laboratory)
26/09/2018, 16:50
Cosmology & Astroparticle Physics
If supersymmetry exists at any scale, it may be a preserved symmetry in the dark sector enforcing a degeneracy between its lowest lying fermions and bosons. In this talk I explore the plausibility of this scenario, the implications for the early universe, and the corresponding signatures. As I will show this completely changes the thermal history of the dark sector resulting in the sector to...
Mr
Lukas Mittnacht
(Johannes-Gutenberg University)
26/09/2018, 17:10
Cosmology & Astroparticle Physics
The cosmological abundance of dark matter can be significantly influenced by the temperature dependence of particle masses and vacuum expectation values. In the paper we illustrate this
point in three simple freeze-in models. The first one, which we call kinematically induced
freeze-in, is based on the observation that the effective mass of a scalar temporarily becomes
very small as the...
Mr
Marco Hufnagel
(DESY Hamburg)
26/09/2018, 17:25
Cosmology & Astroparticle Physics
We study constraints from Big Bang Nucleosynthesis on inert particles in a
dark sector which contribute to the Hubble rate and therefore change the predictions of the
primordial nuclear abundances. We pay special attention to the case of MeV-scale particles
decaying into dark radiation, which are neither fully relativistic nor non-relativistic during
all temperatures relevant to Big Bang...
Martin B. Krauss
(Chalmers University of Technology)
26/09/2018, 17:40
Cosmology & Astroparticle Physics
The discovery of dark matter (DM) at XENONnT or LZ would place constraints on DM particle mass and coupling constants. It is interesting to ask when these constraints can be compatible with thermal production of DM. We address this question within the most general set of renormalizable models that preserve Lorentz and gauge symmetry, and that extend the standard model by one DM candidate of...
Dr
Camilo Alfredo Garcia Cely
(DESY)
26/09/2018, 18:00
Cosmology & Astroparticle Physics
Self-interacting dark matter is a well-motivated solution to the core-vs-cusp and the too-big-to-fail problems of the ΛCDM model. In this scenario, a light particle mediating the self-interactions is typically invoked in order to achieve velocity-dependent effects. In this talk, I will argue that a light mediator is not the only possible way to do that. In particular, I will discuss two new...
Dr
Sebastian Wild
(DESY)
26/09/2018, 18:20
Cosmology & Astroparticle Physics
Light vector mediators can naturally induce velocity-dependent dark matter self-interactions while at the same time allowing for the correct dark matter relic abundance via thermal freeze-out. If these mediators subsequently decay into Standard Model states such as electrons or photons however, this is robustly excluded by constraints from the Cosmic Microwave Background. We study to what...
Yiming Zhong
(Boston University)
26/09/2018, 18:40
Cosmology & Astroparticle Physics
Dark sector models with light or massless mediators naturally introduce elastic and inelastic self-interactions of dark matter. The heat exchange induced by the elastic scattering permits the gravothermal evolution of the halo. Through the evolution, a halo with a cuspy density profile develops a core first but ultimately collapses to a cuspy density profile. We find that a mild inelastic...
