Avodyne
Science Advisor
- 1,396
- 85
Quarks and gluons most definitely "exist" in the sense that the quantum field theory that we believe describes hadrons, QCD, has quark fields and gluon fields in it, in exactly the same way that quantum electrodynamics (QED) has electron/positron fields and photon fields in it. If we set the QCD coupling constant to zero, we get a QFT of free quarks and gluons. Though there is not yet a fully mathematically rigorous construction of QCD, there is ample evidence that we can start with a lattice version and take the zero-spacing limit, with the result being the correct QFT of hadrons. In this sense, QCD is on a much better mathematical footing than QED, which is expected to be a trivial theory that cannot survive removal of the cutoff (equivalently, taking the lattice spacing to zero).