Quark

Key Stage 5

Quarks (q) are a type of fermion and are the constituent parts of hadrons.

The quark is denoted with a lower case q.

Quarks are believed to be fundamental particles but they have never been observed on their own.

Quarks always exist as part of hadron including a baryon, which is a triplet of quarks or a meson which is a quark-antiquark pair.

There are 6 types of quark including:

Up-quark (u) - With a charge of \(+\frac{2}{3}\)e, two of which are found in proton and one of which is found in a neutron.
Down-quark (d) - With a charge of \(-\frac{1}{3}\)e, two of which are found in a neutron and one of which is found in a proton.
Strange-quark (s) - With a charge of \(-\frac{1}{3}\)e which decays quickly via the weak interaction into a down-quark.

(The following are not on all A-level syllabi)

Top-quark (t) - With a charge of \(+\frac{2}{3}\)e which decays quickly via the weak interaction.
Bottom-quark (b) - With a charge of \(-\frac{1}{3}\)e which decays quickly via the weak interaction.
Charm-quark (c) - With a charge of \(+\frac{2}{3}\)e which decays quickly via the weak interaction.