0
$\begingroup$

Neutrinos come in 3 flavors: electron neutrino, muon neutrino, and tau neutrino.

Quarks come in 6 flavors: up, down, top, bottom, strange and charm.

And lets not forget electron, muons and taus too.

Photon is not a massive particle since it has 0 invariant mass.

Why only massive particles can come in many flavors? It is just a co-incidence so maybe there could be more flavors we haven't discovered?

Improve this question
$\endgroup$
2
  • $\begingroup$ If there is a fourth generation of particles that couple to the weak neutral current, its lightest member is too massive to contribute to the known decay width of the $Z$ boson. One source, complete with the famous $N_\nu = 3$ plot from ALEPH at CERN. $\endgroup$
    – rob ♦
    Commented Dec 13, 2021 at 4:12
  • 1
    $\begingroup$ Please see this physics.stackexchange.com/questions/407688/…, my general answer to "why"questions. ( incidentally you have forgotten the gluons) $\endgroup$
    – anna v
    Commented Dec 13, 2021 at 5:00

1 Answer 1

Reset to default
0
$\begingroup$

No one knows why the universe is so constructed; as far as is known, the two more massive generations aren't required to account for phenomena or solve problems in the realm of the first generation.

As pointed out by Rob in his comment, experimental data can be used to place a limit of 3 on the possible number of generations.

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.