  We analyze the dependence on neutrino energy of the gravitational attraction
between ultrarelativistic neutrinos using Special Relativity and the
equivalence principle of inertial and gravitational mass. It is found that when
accounting for the special relativistic increase in particle mass with particle
speed, then this gravitational force reaches the value of the Strong Force at a
neutrino energy of 313 MeV, corresponding to the effective mass of a quark.
This force can sustain the rotational motion of self-gravitating neutrino
triads or electron/positron-neutrino pairs, and thus lead to the self driven
generation of mass, i.e. of hadrons and bosons, the masses of which can be
computed with an astonishing precision of 1\% without any adjustable
parameters.
