What do you mean by subparticles? Could it be subatomic particles?
The great hunt now on in the subatomic particle field is for the Higgs particle. According to the Standard Model, the current theory of particles, the Higgs is what gives mass to the other particles. That is, all the massiveness and gravity in the world is ultimately due to the Higgs.
The Higgs might be seen by the Tevatron accelerator in Illinois within the next few years, or if it's too massive itself for that, we will have to wait for the LEP accelerator at CERN on the French/Swiss border, now under construction. If it isn't found at all, that will be a disaster for contemporary physics.