Someone explain the Standard Model to me

Someone explain the Standard Model to me

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stamp collecting

learn quantum field theory first then you can learn it in 15 minutes

The "Standard Model" is (last I checked, I'm not a physicist) the latest-and-greatest theory about the fundamental questions of WHAT the fundamental particles in the universe actually are, and what the physical forces are that act on those particles. It's the best-available picture to describe why physical shit physically happens.

That said, the people who cobbled it together have a good deal of humility, and recognize that their model is incomplete because really big stuff doesn't marry up with really little stuff, so far as the physical science people are able to tell (again, last I checked). The scientists will happily revise their paradigm (indeed they honestly expect to) once a better model is found, or once other compelling evidence of some kind is found.

The idea of a "basic, unbreakable" (fundamental) particle is ancient, and is presumably still regarded as a useful category. But it turns out that atoms are not such particles, and so their name, which has stuck, is a misnomer. Now, so far as we can tell, /electrons/ are an example of fundamental particles, as are the /quarks/ which comprise protons and neutrons. Also neutrinos, and other cutely named bits, but these are more exotic.

With a little violence to accuracy...

Ya got two main classes of fundamental particles: "bosons" and "fermions".

Fermions have half-integer spin, which for reasons, makes it so no two fermions can share the exact same quantum state. When applied to electrons, this is Pauli's exclusion principle. Fermions are what we usually think of as "matter".

Bosons have integer spin, which for reasons, allows as many bosons of the same quantum configuration to occupy the same state. Bosons are typically "force carriers".

For Fermions, there are two main classes of particles based on what forces they participate in.

One class is that of "Quarks", which interact by the stong, em, weak, and gravitation interactions (all of them). Quarks are divided up into 3 "generations", or pairs of quark types; the up and down, the charm and strange, and the top and bottom quarks. Quarks are not usually observed in isolation, but as composite particles called "hadrons", of which their are 2 and 3 quark varieties, called "meson" and "baryons" respectively. Neutrons and protons are examples of baryons. We don't see quarks by themselves because the way the strong force works; it pulls harder the farther things get apart until a bond snaps, but the energy put into breaking the bond creates new quarks. This is called "confinement".

The other class are "Leptons", and like quarks come in 3 generations; the electron and the electron neutrino. the muon and muon neutrino, and the tau and tau neutrino. Leptons do not feel the strong force, but interact with the em, weak, and gravitation forces. You are familiar with the electron, the muon and tau are just heavier versions. Neutrinos are very ghost like because they have no charge, and thus only interact by weak and gravity forces.

The forces themselves are mediated by the force carriers. Gluon for strong, photon for em, and the W and Z for weak forces. Notice how gravity is not included in your chart. Actually gravity is not accounted for in the standard model, but some extensions include the graviton.

Lastly, all of these particles have anti particle twins with opposite charge.

At the end of the day you have this nomenclature zoo of "-ons", but once you get it straight, it isn't that bad.

Gravity is a comparitively incridibly PATHETIC force which yet exerts it influence everywhere, on everything which has mass, all the time (please correct if I've mis-stated something here). The electromagnetic force is a far, far stronger force, having its conventional uses (a tiny magnet can pull a little piece of iron away from the entire mass of the whole earth, acting on it with gravity). The weak force is something to do with atomic decay, and the strong force (strongest of all) somehow keeps atomic nuclei together IIRC.

Other stuff about flavors, color, etc, to classify these things.

Please let me know how I did Veeky Forums.

Thank you!

> intrinsic angular momentum operator (which corresponds to the rotational freedom) for an electron or photon has only two eigenvalues.

wait so does that mean an electron or photon can't rotate in the z axis? what?