  In a first step, we explore the discovery and analysis potentials of the HERA
collider, with and without polarized beams, in the search for electron-quark
compositeness in the neutral current channel. Then we study the parity
violating effects, for jet production in polarized $pp$ collisions at RHIC,
which could be due to the presence of quark subconstituents or new massive
gauge bosons. We emphasize that the measurement of spin asymmetries in such a
polarized context could give some crucial informations on the chiral structure
of these hypothetical new interactions.
