Questions and answers: the Standard Model
- Which two main groups are the elementary particles divided into?
Matter particles and force carriers.
- Give the names of three leptons and three quarks.
Leptons: electron, electron-neutrino, muon, muon-neutrino, tau, tau-neutrino.
Quarks: up-quark, down-quark, charm-quark, strange-quark, top-quark, bottom-quark.
- Which two kinds of quarks build up protons and neutrons?
Up-quarks and down-quarks.
- What is an antiparticle?
The positron is an example of an antiparticle. It is the antiparticle of the electron, i.e.,
it has the opposite charge of the electron but are otherwise identical.
Antiparticles of neutral particles differ in so-called inner quantum numbers.
- What is a hadron?
A hadron is a particle composed of quarks. The proton and the neutron are examples of hadrons.
- Which are the three kinds of force carrying particles of the Standard Model,
and which forces do they mediate?
The photon mediates the electromagnetic force, i.e. the force that keeps the electron
in a orbit around the nucleus of the atom. The vector bosons mediate the weak force,
which makes particle transformations possible. The gluons are responsible for the strong force,
which keep the quarks together into hadrons.
- How did the scientists come to the conclusion that there should be a Higgs particle?
Since the Standard Model says that all particles are massless, which is wrong,
one had to extend the Standard Model. This mathematical extension by professor Higgs made it possible
to have particles with mass, but it also predicts that it should exist another particle, the Higgs particle.