Perpetual motion was notion which became popular in the 19th century, with various schemes designed to either violate the law of energy conservation, or more ingeniously to violate the second law of thermodynamics. read more
Subatomic particles have no other things to lose that energy to and therefore can keep moving forever. Additionally, you're not getting new energy or work out of their motion. All this is before we get into more esoteric topics like zero point energy and weird happenings at the quantum level. read more
In any case, an orbiting body, ignoring any slight deceleration from impacts with atoms and subatomic particles in space, is"perpetual motion". There is nothing against that. The issue is with perpetual motion"machines". read more
This is, in fact, why we do high-energy particle collisions. The extremely-compressed-energy technique is the only one we know that can allow us to create heavy or exceedingly rare particles that humans have never previously observed. We have no other way to make Higgs particles, for instance. read more