Abstract:

In this seminar I will discuss how connecting two seemingly unrelated facts: neutrino masses and strong CP problem, holds the key in addressing multiple open problems in particle, astroparticle physics and cosmology.

In the first part of the talk I will focus on axion frameworks with color-mediated neutrino masses (Phys.Rev.Lett. 132 (2024) 5, 051801 and Phys.Lett.B 868 (2025) 139629). We propose a KSVZ-type axion framework in which vector-like quarks and colored scalars generate Majorana and Dirac neutrino masses radiatively. The axion also accounts for the observed cosmological dark matter within the pre and/or post-inflationary scenario. The framework predicts distinct axion-to-photon couplings, testable through haloscope and helioscope experiments, as well as potentially significant flavor-violating quark-axion interactions.

In the second part of the talk I will discuss a DFSZ axion model extended with two right-handed neutrinos (νDFSZ) supplemented with flavored Peccei-Quinn symmetries (arXiv:2504.00088 [hep-ph]). In this νDFSZ scheme we systematically determine the simplest quark and lepton flavor patterns compatible with masses, mixing and charge-parity violation data, discuss axion dark matter production in pre and post-inflationary cosmology, and determine the predictions for the axion couplings to photons and fermions.