Quasi-Dirac neutrinos and solar neutrino data

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

We will present an analysis of the solar neutrino data in the context of a 3 + 1 quasi-Dirac neutrino model in which the lepton mixing matrix is given at tree level by the tribimaximal matrix. When radiative corrections are taken into account, new effects in neutrino oscillations, as v(e) -> v(s), could appear. This oscillation is constrained by the solar neutrino data. In our analysis, we have found an allowed region for our two free parameters epsilon and m(1). The radiative correction, epsilon, can vary approximately from 5 x 10(-9) to 10(-6) and the calculated fourth mass eigenstate, m(4), varies in the interval 0.01-0.2 eV, at 2 sigma level. These results are in agreement with the ones presented in the literature in 2 + 1 and 2 + 2 quasi-Dirac models.