Fermion masses, critical behavior and universality

by Ferruccio Feruglio (Istituto Nazionale di Fisica Nucleare)

Friday 19 May 2023, 11:00 → 13:00 Europe/Rome

Aula B (Via della Vasca Navale 84)

Critical phenomena have always played an important role in
understanding physical systems. In particle physics, hints of criticality
recently came from the discovery of the Higgs and from cosmology.
In this talk, we suggest the relevance of critical behavior in the Yukawa sector.
We point out that, among the large variety of existing models
of fermion masses, those based on modular invariance exhibit a significant hint
of a phase transition between a disordered phase and an ordered one.
After reviewing the construction of modular and CP invariant flavour models, we
show that most of them cluster around the fixed point $\tau=i$,
where the system enjoys enhanced symmetry.
Near the fixed point the models exhibit a universal behavior:
mass ratios and mixing angles scale with appropriate powers of the order
parameter, independently of the details of the theory, a feature reminiscent of
systems belonging to the same universality class in second-order phase
transitions.
 

FF_May19_Roma3.pdf