XXth International Conference on Neutrino Physics and Astrophysics
T.Schwetz
Status of Four Neutrino Mass Schemes: A Global and Unified Approach
to Current Neutrino Oscillation Data
We present a unified global analysis of neutrino oscillation data
within the framework of the four-neutrino mass schemes (3+1) and
(2+2). We include all data from solar and atmospheric neutrino
experiments, as well as information from short-baseline experiments
including LSND. If we combine only solar and atmospheric neutrino
data, (3+1) schemes are clearly preferred, whereas short-baseline data
in combination with atmospheric data prefers (2+2) models. When
combining all data in a global analysis the (3+1) mass scheme gives a
slightly better fit than the (2+2) case, though all four-neutrino
schemes are presently acceptable. The LSND result disfavors the
three-active neutrino scenario with only Delta m^2_sol and Delta
m^2_atm at 99.9% CL with respect to the four-neutrino best fit
model. We perform a detailed analysis of the goodness of fit to
identify which sub-set of the data is in disagreement with the best
fit solution in a given mass scheme.
Based on
M.Maltoni, T.Schwetz & J.W.F.Valle,
"Status of Four Neutrino Mass Schemes: A Global and Unified Approach
to Current Neutrino Oscillation Data", Phys. Rev. D (in press)
hep-ph/0112103