Quarks don't have quantum energy states to transition between, hence they aren't subject to radiating photons due to acceleration.
Similar to why the electron in a hydrogen atom doesn't keep emitting radiation and crash into the nucleus once it reaches its ground state... there's no lower state for it to jump to.
Similar to why the electron in a hydrogen atom doesn't keep emitting radiation and crash into the nucleus once it reaches its ground state... there's no lower state for it to jump to.