  In this work we consider a possible conceptual similarity between recent,
amazing OPERA experiment of the superluminal propagation of neutrino and
experiment of the gain-assisted superluminal light propagation realized about
ten years ago. Last experiment refers on the propagation of the light,
precisely laser pulse through a medium, precisely caesium atomic gas, with
characteristic anomalous dispersion and corresponding negative group-velocity
index with very large amplitude between two closely spaced gain lines (that is
in some way similar to quantum theory of the ferromagnetism). It implies
superluminal propagation of the light through this medium. Nevertheless all
this, at it has been pointed out by authors, "is not at odds with causality or
special relativity", since it simply represents "a direct consequence of the
classical interference between ... different frequency components". We suggest
that OPERA experiment can be in some way conceptually similar to the
gain-assisted superluminal light propagation experiment. For this reason we
suppose too that OPERA experiment can be simply explained in full agreement
with causality and special relativity if there is some medium, precisely a
scalar field (e.g. dark matter field, Higgs field or similar) through which
neutrino propagates. We prove that, according to OPERA experiment data,
supposed medium must be non-dispersive while its refractive index must be
positive, smaller but relatively close to 1 (that is in some way similar to
quantum theory of the diamagnetism). If it is true OPERA experiment results do
not mean that special theory of relativity is broken, but they mean detection
of suggested medium, i.e. a scalar field (e.g. dark matter field, Higgs field
or similar).
