Baryon inhomogeneities from the electroweak scale to BBN, CMB and today

by Dr Stefan Stelzl (IFAE)

Wednesday 3 Jun 2026, 14:30 → 16:30 Europe/Rome

1/1-2 - Aula "C. Voci" (Dipartimento di Fisica e Astronomia - Edificio Marzolo)

In this talk I present the implications of precision measurements of light element abundances in concordance with the Cosmic Microwave Background for scenarios of physics beyond the Standard Model that generate large inhomogeneities in the baryon-to-photon ratio. We show that precision Big Bang Nucleosynthesis (BBN) imposes strong constraints on any mechanism that produces large scale inhomogeneities at temperatures of the order or below a TeV. In particular, we find that inhomogeneities of the order of at comoving length scales larger than the comoving horizon at the temperature of are in conflict with the measured light element abundances. Furthermore, I show the evolution of baryon inhomogeneities from BBN, to CMB, to today. In particular, I will highlight that the observed uniformity of D/H measurements yields the strongest constraints on comoving scales larger than around 20 kpc. Finally I briefly highlight the phenomenological consequences of these probes on models beyond the SM.