3+1 and 3+2 Sterile Neutrino Fits
  We present the results of fits of short-baseline neutrino oscillation data in
3+1 and 3+2 neutrino mixing schemes. In spite of the presence of a tension in
the interpretation of the data, 3+1 neutrino mixing is attractive for its
simplicity and for the natural correspondence of one new entity (a sterile
neutrino) with a new effect (short-baseline oscillations). The allowed regions
in the oscillation parameter space can be tested in near-future experiments. In
the framework of 3+2 neutrino mixing there is less tension in the
interpretation of the data, at the price of introducing a second sterile
neutrino. Moreover, the improvement of the parameter goodness of fit is mainly
a statistical effect due to an increase of the number of parameters. The CP
violation in short-baseline experiments allowed in 3+2 neutrino mixing can
explain the positive antinu_mu -> antinu_e signal and the negative nu_mu ->
nu_e measurement in the MiniBooNE experiment. For the CP-violating phase we
obtained two minima of the marginal chi^2 close to the two values where
CP-violation is maximal.
