Hypermagnetic Baryogenesis

Kazuharu Bamba, C. Q. Geng and S. H. Ho Department of Physics, Kinki University, Higashi-Osaka 577-8502, Japan Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300 Abstract We study a new scenario for baryogenesis due to the spontaneous breaking of the CPT invariance through the interaction between a baryon current and a hypermagnetic helicity. The hypermagnetic helicity (Chern-Simons number) of U(1)Y provides a CPT violation background for the generation of baryons via sphaleron processes, which protects these baryons from the sphaleron wash-out effect in thermal equilibrium. It is shown that if the present amplitude of the resultant magnetic fields are sufficiently large, for a wide range mass scale (from TeV to the Planck scale), the observational magnitude of the baryon asymmetry of the Universe can be realized.