Electroweak baryogenesis without electric dipole moments

by Majid Ekhterachian (Scuola Normale Superiore di Pisa)

Thursday Oct 22, 2026, 12:00 PM → 2:00 PM Europe/Madrid

C7b/058 - Seminar (IFAE Main Building C7b)

 

Electroweak baryogenesis offers an attractive explanation for the observed baryon asymmetry, but the new CP violation it requires is strongly constrained by searches for the electron electric dipole moment (EDM). I will discuss a scenario that can robustly evade these constraints. The CP phase responsible for baryogenesis arises predominantly from spontaneous breaking of CP, is large during the electroweak phase transition, and relaxes to a negligible value today. Composite Higgs theories offer a natural setting for this scenario, with the Higgs and a CP-odd singlet arising as pseudo-Nambu–Goldstone bosons. I will show that the models considered in the literature require an additional tuning beyond the usual one associated with the Higgs mass. This extra tuning is needed to keep the singlet light while generating Higgs-singlet quartic interactions strong enough to support a first-order transition. I will then present two classes of models that resolve this double-tuning problem: one uses symmetry-breaking sources that generate quartics without leading-order mass terms, while the other uses large representations to enhance quartics relative to masses.