  The free massless superparticle is reanalysed, in particular by performing
the Gupta-Bleuler quantization, using the first and second class constraints of
the model, and obtaining, as a result, the Weyl equation for the spinorial
component of the chiral superfield. Then we construct a superconformal model of
two interacting massless superparticles from the free case by the introduction
of an invariant interaction. The interaction introduces an effective mass for
each particle by modifying the structure of fermionic constraints, all becoming
second class. The quantization of the model produces a bilocal chiral
superfield. We also generalise the model by considering a system of
superconformal interacting particles and its continuum limit.
