Speaker: Toni Bertólez-Martínez, University of Wisconsin-Madison
Abstract: As a new postdoc in the department, I will introduce my research around cosmological neutrinos. In the first part of the talk, I will focus on the physical effects that neutrino masses have in cosmological observables, which allow cosmology to place the most stringent bounds on neutrino masses as of today. Then, I will show how CMB bounds can be relaxed not only by a different assumption on the cosmological model, but by non-standard properties of the neutrino sector. This motivates a novel framework which allows to quantify which properties of neutrinos in cosmology we are actually measuring. In the second part of the talk, I will introduce a model which could explain the origin of neutrino masses by a coupling to ultralight dark matter (ULDM). I will introduce a consistent treatment of the coupled neutrino-UDLM oscillations and use Big Bang Nucleosynthesis to put competitive bounds on neutrino-ULDM interactions. This talk is based in 2411.14524 and 2509.22867, respectively.