Theory seminar (11am): Maksym Ovchynnikov: GeV-mass new physics particles: status and searches

Thursday 17 Jul 2025, 11:00 → 12:00 Europe/Amsterdam

Veltman Centre (Nikhef)

I discuss status and searches of feebly interacting particles (FIPs) in the GeV mass range. I begin by underscoring the synergy between cosmological and laboratory searches for FIPs. On the laboratory side, I survey the intensity frontier experiments poised to exclude or, potentially, discover them. A central theme is the role of theoretical uncertainties in FIP phenomenology and how they shape experimental constraints and sensitivities. On the cosmology side, I delve into FIPs’ effects on Big Bang Nucleosynthesis and the Cosmic Microwave Background, with a special focus on the neutrino decoupling epoch - the principal boundary of these observations. Finally, I highlight recent advances in modeling how decaying FIPs influence the primordial neutrino background at MeV temperatures.