Talk:Elementary particle

I think the particle counting for the Standard Model bosons is faulty. Why do you count the 8 color combinations for gluons, when you don't count the three possibilities for each quark? I like the way the Fermilab poster counts the particles: 6 quarks (u,d,c,s,t,b), 6 leptons (e,mu,tau,e_nu,mu_nu,tau_nu), the photon, the W, the Z, and the gluon. That's every standard model particle that's been observed, and uniformly leaves out antiparticles and color. I will change the article to this in a few days, unless there are objections. -- SCZenz 20:52, 15 July 2005 (UTC)[reply]

Leaving out color makes no more sense than leaving out flavor, generation or chirality. The only real way to discuss "numbers" of particles is with degrees of freedom. -- Xerxes 02:25, 2005 July 16 (UTC)

But if there are 8 gluons, then there are 18 quarks. It doesn't make any sense to only count color for one and not the other. It seems to me that the color is being counted only for gluons in order to create an artificial parallel between the number of fermions and the number of gague bosons. -- SCZenz 05:19, 16 July 2005 (UTC)[reply]

Not 18. There are (color)(flavor)(generation)(spin) 3×2×3×4 = 72 degrees of freedom in the quark fields. Versus (color)(spin) 8×2 = 16 gluonic ones. 24 leptonic, 12 massless (24 massive) neutrino, 9 W/Z, 2 photon, 1 Higgs and 2 graviton. If I haven't miscounted... -- Xerxes 06:14, 2005 July 16 (UTC)

Well, the page wasn't counting spin (it claims 6 quarks, 6 leptons, 8 gluons, 1 Z, 2 W's, and 1 photon). If you take away your spin DoF, you do get what I said: "if there are 8 gluons, there are 18 quarks." You may be technically correct that we should count everything, but I think this would very much confuse the people who read the page (who are not, in general, physicists). If you're willing to accept experimentally-motivated arguments, I would suggest counting the particles that we can differentiate from each other in observations (and cut down the number by ignoring stuff that more or less just flips, like spin and parity). In any case my assertion that the particle counting on the page is inconsistent is still solid. -- SCZenz 15:17, 16 July 2005 (UTC)[reply]

I guess my basic point is that the notion of there being some "number" of elementary particles doesn't make a lot of sense if you're not counting degrees of freedom. If you can say that spin is "just flips", I could just as easily say that flavor is "just flips of weak isospin space". And while it's not easy, it's certainly possible experimentally to distinguish between different spins of particle. Think astrophysics polarization experiments, or Wu's demonstration of parity-breaking. I think a careful counting of degrees of freedom would be accessible to a novice reader; it's just counting and multiplication. -- Xerxes 16:43, 2005 July 16 (UTC)

A novice reader might be able to follow a DoF-counting, but I am not sure he would not find it very enlightening. Besides, why are you neglecting the degrees of freedom a quark has to be off-shell, or to have any arbitrary momentum, or to exist at any point in spacetime? Doesn't this mean there are, in fact, an uncountable number of quarks? I agree that how one counts particles is a bit arbitrary, but the most common (and most sensible, IMHO) approach to popularizing physics is to count particles that can be differentiated in an experiment--i.e. that have different masses, or different lifetimes, or carry a different force. And then, reduce that set, by ignoring spin and charge and parity, which are detectable but (mostly) flip the behavior of the particle in some obvious way. In the end, the question here is not what is true (which can't possibly have a clear meaning when counting particles), but what will be most educational thing to say on Wikipedia. -- SCZenz 23:37, 16 July 2005 (UTC)[reply]

Well, you don't count spacetime DoF because every particle lives in the same spacetime. But not so for spin. There's no sense in making statements that are false just because they're easier to understand than the truth. Just say half-truths like: "There are 6 flavors of quark." "There are 8 colors of gluon." There's no need to say what the "total number" of particles is. -- Xerxes 00:08, 2005 July 17 (UTC)

There is no capital-T truth in physics. You count particles different ways--sometimes the neutral kaon and its antiparticle are two particles, other times the K-long and K-short (linear combinations thereof) are two particles, and sometimes they're all just collections of the "real" particles, the quarks--depending on what you're doing. We can't ever prove that any of the things on this page are elementary particles at all, in fact--all we can say is that the only good model we have assumes they are, and there's no evidence to the contrary. Everything a physicst ever says is a severe oversimplifcation anyway. The bottom line is counting six quark flavors, and eight gluon colors is comparing apples and oranges, so this article should be changed somehow. To discuss how, I'm going to start a new, less indented, thread below. -- SCZenz 00:53, 17 July 2005 (UTC)[reply]

By all means, let's say there are six quark flavors, but there's no reason to say there are eight gluon colors unless we list the quark colors also. It's probably better to get rid of the particle-counting, and do away with the current non-sensical 12 fermion-12 boson parallel. I'll rewrite a bit, when I get the chance, and we can argue some more then. -- SCZenz 00:53, 17 July 2005 (UTC)[reply]

How much crack are you guys on?

How much crack are you guys on? -- Anon

Good question! We're physics grad students, so probably a lot. -- SCZenz 15:02, 24 July 2005 (UTC)[reply]

Will changes be made?

I was wondering if you are still going to make changes. As someone with little knowledge of this topic, I can tell you what would be confusing to someone like myself, and thus help you to make this a better, more easily understood article.