Some constraints on the Yukawa parameters in the neutrino modification of the Standard Model (νMSM) and CP-violation

The equations connecting elements of the Yukawa matrix to elements of the active neutrino mass matrix in the nu MSM theory (an extension of the Standard Model by a singlet of three right-handed neutrinos) was analyzed, and explicit relations for the ratio of the Yukawa matrix elements and elements of the active neutrino mass matrix were obtained. This relation can be used for getting more accurate constraints on the model parameters. Particularly, with the help of the obtained results we investigated CP-violating phase in the nu MSM theory. We demonstrate that even in the case when elements of the active neutrino mass matrix are real the baryon asymmetry can be generated also.