Radiative corrections to neutrino mass matrix in the Standard Model and beyond

We study the effect of radiative corrections on the structure of neutrino mass matrix. We analyze the renormalization of the matrix from the electroweak scale mZ to the scale m0 at which the effective operator that gives masses to neutrinos is generated. Apart from Standard Model and MSSM, non-standard extensions of SM are considered at a scale mX intermediate between mZ and m0. We find that the dominant structure of the neutrino mass matrix does not change. SM and MSSM corrections produce small (few percents) independent renormalization of each matrix element. Non-standard (flavor changing) corrections can modify strongly small (subdominant) matrix elements, which are important for the low energy phenomenology. In particular, we show that all sub-dominant elements can have purely radiative origin, being zero at m0. The set of non-zero elements at m0 can be formed by (i) diagonal elements (unit matrix); (ii) Mee and Mμτ ; (iii)Mee and μτ -block elements; (iv) μτ -block elements. In the case of unit matrix, both atmospheric and solar mixing angles and mass squared differences are generated radiatively. Ref.SISSA 95/2002/EP hep-ph/0212263 PACS number: 14.60.Pq, 11.10.Hi, 12.60.-i ∗ [email protected] † [email protected]