  From a mathematical point of view velocities can be larger than c. It has
been shown that Lorentz transformations are easily extended in Minkowski space
to address velocities beyond the speed of light. Energy and momentum
conservation fixes the relation between masses and velocities larger than c,
leading to the possible observation of negative mass squared particles from a
standard reference frame. Current data on neutrinos' mass square yeld negative
values, making neutrinos as possible candidates for having speed larger than c.
In this paper, an original analysis of the SN1987A supernova data is proposed.
It is shown that all the data measured in '87 by all the experiments are
consistent with the quantistic description of neutrinos as combination of
superluminal mass eigenstates. The well known enigma on the arrival times of
the neutrino bursts detected at LSD, several hours earlier than at IMB, K2 and
Baksan, is explained naturally. It is concluded that experimental evidence for
superluminal neutrinos was recorded since the SN1987A explosion, and that data
are quantitatively consistent with the introduction of tachyons in Einstein's
equation.
