Cosmology Journal Club on Friday 12th

12.12.2025 10:15 – 11:00

Dear all,

we warmly invite you to join us on Friday, December 12th, at the usual Journal Club time (10:15 a.m.) in EP234 for a talk by Dr. Fumio Uchida (IBS, Daejeon, South Korea).

TITLE
Primordial magnetic fields during the electroweak crossover and baryogenesis from magnetic helicity decay

ABSTRACT
Magnetic fields are ubiquitous in the present universe. Their existence has been discussed as a relic from the early universe, which may be a consequence of some physics beyond the Standard Model. In particular, if primordial magnetic fields were generated at high temperatures, the electroweak symmetry breaking implies a transition from the hyper- (U(1)Y) magnetic field in the high-temperature phase to the ordinary (U(1)em) magnetic field in the low-temperature phase. However, this transition process has been understood only naively. We examine the electroweak symmetry breaking from the viewpoint of symmetry-breaking pattern, and characterize the evolution of magnetic fields across the crossover in a gauge-invariant manner. In particular, we point out that the baryogenesis scenario based on primordial magnetic fields suffers from both quantitative and qualitative uncertainties. This makes the previously-proposed cosmological constraints on primordial magnetic fields, which concern two baryon asymmetry problems, less robust. Consequently, the co-genesis scenario for the intergalactic magnetic fields and the baryon asymmetry of the universe may revive.


Best regards,
Antonino and Alberto

Lieu

Bâtiment: Ecole de Physique

234

entrée libre