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The Standard Model Chart


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The standard model of particle physics is summarized in a chart which is slightly reminiscent of chemistry's Periodic Table. The chart is a simplified reference that is not complete, partly because the standard model is not complete. It does not, for example, take gravity into account. At the particle level, of course, gravity is a vanishingly small force. But we would like to put it in the chart anyway; we just do not have the facts to do it. The chart also has nothing to say about cold dark matter and forces which have not been integrated into the Standard Model. The anti-particles are omitted, but only because they are symmetrical with particles and including them would be redundant. The chart also do not include every property, such as "color."

The only things on the chart likely to be recognized by the person on the street are the electron and the photon. The familiar proton and neutron are not fundamental particles, so they do not show up on the chart.

"Standard Model Chart"

The chart of fundamental particles can be divided and grouped in several ways. Masses in the chart, where there is any, are expressed in terms of energy.

The first three columns (blue and green) are fermions. They have a spin of one half. The particles in the first column are first generation particles which are stable and are found in ordinary matter today. The particles in second are much more massive, are unstable, and may be found in cosmic rays. The particles in the third column are even more massive and today are found only particle accelerators.

The top two rows of the first three columns are the quarks. They have fractional electric charges, and more notably have an attribute called color. Color has nothing whatever to do with the color of visible light and of objects in light. The values of the color attributes are Red, Green, Blue, and the anti-colors Anti-red, Anti-green, and Anti-blue. The names of the quarks are also called their flavors, and again, the normal world meanings of the names should not be taken as having anything in particular to do with the quarks.

The lower two rows of the first three columns are call leptons.

The fourth and fifth column are the bosons.

The fourth column are the gauge bosons. They mediate the three forces of the standard model. The gluon mediates the strong force. It affects only the quarks and is associated with color changing. Since only the quarks have color, the gluon does not affect other fermions. The photo mediates the electromagnetic force, and so affects only those particles which have electric charge, which are all the quarks and the top row of the leptons. The Z and W bosons mediate the weak force, and so play a role with all of the fermions. The Z boson has no charge, while the W boson may have a positive or negative charge. When charges must be balanced, it is easy to determine which of weak-force bosons is involved.


Sources:

  1. Chart By MissMJ - Own work by uploader, PBS NOVA [1], Fermilab, Office of Science, United States Department of Energy, Particle Data Group, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4286964

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Categories: Standard Model


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