Count the particles this topic has named: six quark flavors, the electron, the neutrino, the photon, the gluon, the W boson, the Z boson. Twelve particles and three carried forces. Is there one chart that holds them all?
Physicists built exactly that chart, and the theory behind it is one of the most tested ideas in science. Lay the particles out in columns: the quarks in one, the leptons in another, the force-carrier bosons in a third.
A standard-model chart is the theory at a glance. To find the electron, look in the lepton column.
One honest note: the chart on this page is simplified. The full chart lists six leptons. You have met the two this course names, the electron and the neutrino. Composite particles never appear on the chart: the proton, the neutron, and whole atoms are made of smaller particles, and the chart lists only fundamental ones.
A friend asks what the standard model is. What is the short answer?
The standard model is a theory, and a chart shows it at a glance.
The standard model is the theory that catalogs all known fundamental particles and the forces they exert.
Its particles are the quarks, the leptons, and the force-carrier bosons.
Where does the up quark sit on a standard-model chart?
The up is one of the six quark flavors.
In the quark column.
Physicists keep one complete catalog of nature's particles. What does it list?
On a standard-model chart, the electron sits among which group?
One theory catalogs the fundamental particles and the forces they exert. What is it called?
Which three groups of particles does the standard model catalog?
On a standard-model chart, the neutrino appears in which column?
Which of these does the standard model catalog?