Description
Right handed neutrinos are introduced to the Standard Model to explain the observed active neutrino masses. If CP is violated during their radiative decays, an asymmetry between two circularly--polarised photons can be generated. The CP asymmetry is somehow connected to circular polarisation. Therefore, observations of such polarised signals potentially lead to a measurement of the CP violation in the process. Here, I will discuss the connection between these two asymmetries for Dirac neutrinos and then apply this formalism to a minimal seesaw mode.