Question: How many different particles are there?

Philip Ratcliffe answered on 17 Nov 2014:

First, here are what we consider to be “matter” particles:
6 quarks (up, down, strange, charm, top and bottom)
3 charged leptons (electron, muon and tau)
3 neutrinos (one for each charged lepton)
although the important ones for the universe as we see it are:
up, down, electron and its neutrino.
Then we have the force fields, which we still consider particles:
the photon (for electromagnetism)
the W+, W- and Z° (for the weak nuclear force)
the gluons, 9 of them (for the strong nuclear force)
Finally, we have the Higgs particle recently found at CERN, Geneva (the particle that gives the others their masses).
There should also be a graviton, but nobody has been able to detect one yet.
Of course, there may be many more that we’ve never seen (probably because they’re too heavy to produce in our experiments).