Editing Charm quark (section)

== Characteristics ==
The charm quark is a [[Generation (particle physics)|second-generation]] up-type quark.{{sfn|Harari|1977|p=6}}{{sfn|Gersabeck|2014|p=2}} It carries charm, a [[quantum number]].{{sfn|Appelquist|Barnett|Lane|1978|p=388}} According to the 2022 ''Particle Physics Review'', the charmed quark has a mass of {{val|1.27|0.02|ul=GeV/c2}},{{efn|The ''Particle Physics Review'' uses the unit GeV instead of GeV/''c''<sup>2</sup>.{{sfn|Workman et al.|2022|p=32}} This is because particle physics uses [[natural units]], in which the [[speed of light]] is set to be one.{{sfn|Thomson|2013|p=31}} The ''Review'' also notes this mass corresponds to the "running" mass in the [[minimal subtraction scheme]] (MS scheme).{{sfn|Workman et al.|2022|p=32}}}} a charge of +{{sfrac|2|3}}&nbsp;[[elementary charge|''e'']], and a charm of +1.{{sfn|Workman et al.|2022|p=32}} The charm quark is more massive than the strange quark: the ratio between the masses of the two is about {{val|11.76|+0.05|-0.10}}.{{sfn|Workman et al.|2022|p=32}}

The [[CKM matrix]] describes the weak interaction of quarks.{{sfn|Thomson|2013|p=368}} As of 2022, the values of the CKM matrix relating to the charm quark are:{{sfn|Workman et al.|2022|pp=262–263}}
<math display="block">
\begin{align}
|V_\text{cd}| & = 0.221 \pm 0.004 \\
|V_\text{cs}| & = 0.975 \pm 0.006 \\
|V_\text{cb}| & = (40.8 \pm 1.4) \times 10^{-3}
\end{align}
</math>

<!-- === Particles containing the charm quark=== --->
[[File:Baryon Supermultiplet using four-quark models and half spin.svg|thumb|A [[supermultiplet]] of baryons that contain the up, down, strange and charm quarks with half-spin]]
<!-- {{Main|List of mesons|Charmed baryon}} --->

Charm quarks can exist in either "open charm particles", which contain one or several charm quarks, or as charmonium states, which are bound states of a charm quark and a charm antiquark.{{sfn|Gersabeck|2014|p=2}} There are several charmed mesons, including {{subatomic particle|D+-}} and {{subatomic particle|D0}}.{{sfn|Workman et al.|2022|pp=43–45}} Charmed baryons include {{subatomic particle|Charmed Lambda|link=yes}}, {{subatomic particle|Charmed Sigma|link=yes}}, {{subatomic particle|Charmed Xi|link=yes}}, {{subatomic particle|Charmed Omega|link=yes}}, with various charges and [[resonance (particle physics)|resonances]].{{sfn|Workman et al.|2022|pp=100-4}}

=== Production and decay ===
Particles containing charm quarks can be produced via electron–positron collisions or in hadron collisions.{{sfn|Gersabeck|2014|pp=3–4}} Using different energies, electron–positron colliders can produce psi or [[upsilon meson|upsilon]] mesons.{{sfn|Gersabeck|2014|p=3}} Hadron colliders produce particles that contain charm quarks at a higher [[Cross section (physics)|cross section]].{{efn|According to [[Mark Thomson (physicist)|Mark Thomson]], a ''cross section'' in particle physics is a measure of quantum mechanical probability for the interaction.{{sfn|Thomson|2013|p=26}} It is the ratio between the interaction rate per target particle and the incident particle flux.{{sfn|Thomson|2013|p=69}}}}{{sfn|Gersabeck|2014|p=4}} The [[W boson]] can also decay into hadrons containing the charm quark or the charm antiquark.{{sfn|Thomson|2013|p=412}} The Z boson can decay into [[charmonium]] through charm quark fragmentation.{{sfn|Braaten|Cheung|Yuan|1993}} The Higgs boson can also decay to {{subatomic particle|J/Psi}} or {{subatomic particle|charmed eta}} through the same mechanism. The decay rate of the Higgs boson into charmonium is "governed by the charm-quark [[Yukawa coupling]]".{{sfn|Han|Leibovich|Ma|Tan|2022}}

The charm quark can decay into other quarks via weak decays.{{sfn|Gersabeck|2014|p=2}} The charm quark also annihilates with the charm antiquark during the decays of ground-state charmonium mesons.{{sfn|Gersabeck|2014|p=2}}