We study the special features emerging from a three lepton generation analysis of the available neutrino oscillation data (solar, atmospheric and LSND). First we find that it is possible to explain all three sets of data in terms of the standard left handed neutrinos without the need of sterile neutrinos.Second we find a significant difference in the mass matrix extracted from the data, depending on the analysis (without or with LSND), if the mass of the lightest neutrino, which cannot be determined from the neutrino oscillation data alone, is relatively small, i.e ≤0.1 eV. To compare with other processes we used the R-parity violating Minimal Supersymmetric Standard Model (R p / -MSSM) for the theoretical description of the neutrino masses. Using the oscillation data we were able to constrain the parameters of the model. In particular we were able to obtain values for the coupling constants of the R p / -MSSM.
PACS number(s):{}Searches for neutrino masses have intensively been performed during the last decades.But till now no evidence for massive neutrinos was found in experiments aiming to measure the mass directly, but only upper limits were set as follows [1]On the other hand some hints for massive neutrinos have been seen more than 30 years ago in experiments measuring the electron neutrino flux coming from the sun [2]. In these experiments the flux of ν e coming from the sun to the earth was found to be much smaller