Axion inflation as the origin of baryon asymmetry of the Universe and cosmological magnetic fields

by Prof. Kohei Kamada (University of Chinese Academy of Sciences)

Tuesday 24 Dec 2024, 14:00 → 16:00 Asia/Shanghai

B105 (CHEP)

Pseudoscalar inflation or axion inflation is one of the most well-motivated models of inflation because the approximate shift symmetry guarantees the flatness of the potential against the quantum corrections. The CP and shift symmetric properties of pseudoscalar inflaton allows it to have a coupling to the Chern-Pontryagin density of the gauge fields. In this talk, I will argue that if the inflaton has such a coupling to the hyper U(1) gauge fields in the Standard Model, it can give a significant impact on the baryon asymmetry of the Universe. Namely, through the chiral anomaly, baryon asymmetry is directly produced at the end of inflation together with the helical magnetic fields. Although this asymmetry suffers from the sphaleron washout, I will show that it is likely that the present baryon asymmetry can be explained together with the contribution from the hypermagnetic helicity decay. I will explain some details of relevant phenomena in the scenario. I will also show a variant of this scenario in the gauged B-L theory. 

CV: 
Kohei Kamada is a distinguished researcher at Haongzhou Institute for Advanced Study, University of Chinese Academy of Sciences. He received his Ph.D from the University of Tokyo in 2011 and has worked at Deutsches Elektronen-Synchrotron (DESY), École Polytechnique Fédérale de Lausanne (EPFL), Arizona State University, and Institute for Basic Science as a postdoc. From 2018 to 2023, he has worked at the University of Tokyo as an Assistant Professor before joining HIAS. His research interest centers on the early Universe cosmology and particle phenomenology. His main works include theoretical consistency of Higgs inflation and baryogenesis from magnetic fields. He is also known as his work on the chiral effects in cosmology.