Electron orbital radius

No, but quarks and leptons (e.g., electrons) all have spin 1/2. Photons and the other messenger particles have spin 1. I think the graviton is the only(?) particle with spin 2. Now that I think about it, I’m not sure that there are any spin 0 particles.

The Standard Model has fermions (matter constituents) with spin 1/2, 3/2, 5/2,… and bosons (force carriers) with spin 0, 1, 2,…

From that chart (I have it on my wall), photons have spin 1, quarks and electrons and protons have spin 1/2, the omega particle has spin 3/2, and pions and kaons have spin 0.

The more interesting spin 0 particle in the minimal Standard Model is the Higgs boson. No, it hasn’t been observed, but it’s the only one regarded as fundamental. While mesons, including the pions and kaons, can be spin 0, they are merely composite.

If quarks are fundamental, right? :slight_smile: