  A statistical model is proposed which ascribes the Z^0 mass to the screening
properties of the neutrino Fermi sea (neutrino vacuum). Concerning the fermion
masses, some puzzling features of the Higgs mechanism are examined. Arguments
are advanced, based on the Zitterbevegung theory of the electron substructure,
showing that in low energy experiments electron behaves as an extended
distribution of charge, though its size comes out less than 10^-16 cm in high
energy experiments. This might be a clue for explaining the origin of fermion
masses without resorting to Higgs field.
