Neutrino Masses and Beyond the Standard Model

Fermions gain their Dirac masses by the Higgs mechanism, but the matter content of the Standard Model (SM) doesn''t include right handed neutrinos. So neutrinos are assumed to be massless in the SM. Recent experiments revealed that three neutrinos associated with three charge leptons have tiny masses. It is essential to extend SM. This thesis works under the Higgs scalar triplet model, as a little extension to the SM by employing one Higgs triplet. The additional scalar fields may be the candidates for dark matters. The branch ratio of the fields decay into leptons is discussed. If the model can explain the recent observations on PAMELA and ATIC searches, it is possible to determine which hierarchy of mass differences is in the neutrino''s nature