Speaker: Andrew Long, University of Chicago, Kavli Institute for Cosmological Physics (KICP)
Abstract: Due to quantum anomalies in the Standard Model, baryon number is violated in the early universe in the presence of a helical (hyper)magnetic field. I will discuss how the matter / anti-matter asymmetry of the universe may have been created from the decaying helicity of a primordial (hyper)magnetic field. This scenario has the interesting feature that baryogenesis occurs without the violation of (B-L), since the (B+L) asymmetry generated by the hypermagnetic field counteracts the washout by electroweak sphalerons. After the electroweak crossover, the hypermagnetic field becomes an electromagnetic field. Thus, observations of the relic, intergalactic magnetic field today may inform our understanding of the cosmological excess of matter over anti-matter.