#StudentSeminar: Early-Universe constraints on the electron mass and other observables

por Michela Garramone (IFIC (CSIC - UV) and UniTo)

lunes 5 oct. 2026 15:00 → 16:30 Europe/Madrid

1001-Primera-1-1-1 - Paterna. Seminario (Universe)

Fundamental constants are a crucial ingredient in our understanding of particles and fields. Our knowledge comes mostly from observations performed at terrestrial experiments nowadays, but this cannot provide us any probe about their value throughout the Universe's history. For this reason, it is interesting to investigate whether the fundamental parameters of the Standard Model have always had the same values throughout cosmic history.

The aim of this work is to evaluate the effect of a non-standard electron mass in the early Universe picture, in particular considering the neutrino decoupling scenario and Big Bang Nucleosynthesis (BBN). By comparing the light element abundances predicted by BBN with their observed values and applying constraints on the effective number of relativistic species N_eff , we derive the earliest bound on the value of the electron mass in the early universe, which is remarkably similar to the one measured at terrestrial experiments nowadays. This confirms that the value of the electron mass has been constant throughout most of the life of the Universe.

We will see how this analysis can be extended to other fundamental parameters relevant to the early Universe, and what we can learn from studying their possible variation over cosmic history.