ar X iv : h ep - p h / 99 04 39 5 v 2 3 M ay 1 99 9 Naturalness of nearly degenerate neutrinos

ar X iv : h ep - p h / 99 04 39 5 v 1 1 9 A pr 1 99 9 Naturalness of nearly degenerate neutrinos

If neutrinos are to play a relevant cosmological role, they must be essentially degenerate. We study whether radiative corrections can or cannot be responsible for the small mass splittings, in agreement with all the available experimental data. We perform an exhaustive exploration of the bimaximal mixing scenario, finding that (i) the vacuum oscillations solution to the solar neutrino problem ...

ar X iv : h ep - p h / 99 06 38 1 v 2 6 S ep 1 99 9 Nature of neutrinos in the light of present and future experiments

Two general models with hierarchical and almost degenerate neutrino masses, which are able to explain the solar and atmospheric anomalies are investigated. We show how neutrinoless double beta decay experiments discern Dirac and Majorana natures of neutrinos. The strongest result is, that almost degenerate neutrinos with masses above 0.22 eV combined with the SMA MSW must be Dirac particles. In...

ar X iv : h ep - p h / 99 05 46 9 v 1 2 5 M ay 1 99 9 DESY 99 – 060 hep - ph / 9905469 May 1999 W Boson Production at NLO ∗

We discuss W boson production at HERA including NLO QCD corrections. A detailed comparison with previous work is presented.

ar X iv : h ep - p h / 99 05 38 1 v 1 1 8 M ay 1 99 9 Nearly degenerate neutrinos , Supersymmetry and radiative corrections

If neutrinos are to play a relevant cosmological rôle, they must be essentially degenerate with a mass matrix of the bimaximal mixing type. We study this scenario in the MSSM framework, finding that if neutrino masses are produced by a seesaw mechanism, the radiative corrections give rise to mass splittings and mixing angles that can accommodate the atmospheric and the (large angle MSW) solar n...

ar X iv : h ep - p h / 94 05 25 5 v 1 9 M ay 1 99 4 6453 April , 1994 ( T / E ) Spin , Mass , and Symmetry