Dai-Freed anomaly in the standard model and topological inflation

Abstract

Abstract When we impose discrete symmetries in the standard model we have Dai-Freed global anomalies. However, interestingly if we introduce three right-handed neutrinos we can have an anomaly-free discrete Z 4 gauge symmetry. This Z 4 symmetry should be spontaneously broken down to the Z 2 symmetry to generate the heavy Majorana masses for the right-handed neutrinos. We show that this symmetry breaking naturally generates topological inflation, which is consistent with the CMB observations at present and predicts a significant tensor mode with scalar-tensor ratio r > 0.03. The right-handed neutrinos play an important role in reheating processes. The reheating temperature is as high as ∼ 108 GeV, and non-thermal leptogenesis successfully takes place.

Keywords

• Cosmology of Theories BSM
• Baryo-and Leptogenesis
• Early Universe Particle Physics
• Anomalies in Field and String Theories