Dark Matters 2022

Session

DM pheno theory

1 Dec 2022, 09:40

Salle Solvay (NO Buidling, 5th floor) (ULB, Campus de la Plaine)

14. Multi-phase criticality

Martti Raidal (National Institute of Chemical Physics and Biophysics (EE))

01/12/2022, 09:40

I present a scale-invariant Higgs-dilaton model of dynamical symmetry breaking and dark matter which, in the multi-phase criticality regime, generates a huge hierarchy between the electroweak and new physics scales in a technically natural way. The hierarchy follows from tiny scalar couplings required by the multi-phase criticality. I discuss dark matter freeze-out and freeze-in processes as...

15. Minimal sterile neutrino dark matter

Marco HUFNAGEL

01/12/2022, 10:20

We propose a novel mechanism to generate sterile neutrinos νs​ in the early Universe, by converting ordinary neutrinos να in scattering processes νs να → νs νs. After initial production by oscillations, this leads to an exponential growth in the νs abundance. We show that such a production regime naturally occurs for self-interacting νs, and that this opens up significant new parameter space...

32. The domain of thermal dark matter, and a hot, dark history of the Universe

Rupert Coy (ULB)

01/12/2022, 10:45

Thermal dark matter (DM) covers a well-motivated class of candidates. In this talk, I will firstly consider DM in a hidden sector with temperature T', and find the allowed, model-independent parameter space in terms of the DM mass and the ratio T'/T. Then I will look specifically at the T'/T >> 1 case, taking dark QED as a representative example, and show how large entropy production allows...

16. Metastable bound states in the early universe and dark matter freeze-out

Kalliopi Petraki

01/12/2022, 11:40

If dark matter couples to force mediators that are much lighter than itself, then bound states appear in the spectrum of the theory. The formation and decay of metastable dark matter bound states in the early universe can deplete the dark matter abundance, thereby changing the predicted parameters and the interpretation of experimental constraints. I will discuss how metastable bound states...

17. Light thermal relics enabled by a second Higgs

Johannes Herms (Max-Planck-Institut für Kernphysik)

01/12/2022, 12:20

Sub-GeV thermal relic dark matter typically requires the existence of a light mediator particle. We introduce the light two-Higgs-doublet portal, illustrated by a minimal UV-complete model for sub-GeV DM with kinematically forbidden annihilations into leptons. All new physics states in this scenario lie at or below the electroweak scale, affecting Higgs physics, the muon anomalous magnetic...