Editing Standard Model (section)

=== Fermions ===
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[[File:Standard Model.svg|upright=1.5|right|thumb|The pattern of [[weak isospin]], T<sub>3</sub>, [[weak hypercharge]], Y<sub>W</sub>, and [[color charge]] of all known elementary particles, rotated by the [[Weinberg angle|weak mixing angle]] to show electric charge, Q, roughly along the vertical. The neutral [[Higgs field]] (gray square) breaks the [[electroweak symmetry]] and interacts with other particles to give them mass.]]
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The Standard Model includes 12 [[elementary particle]]s of [[Spin (physics)|spin]] {{1/2}}, known as [[fermion]]s.<ref name=":0">{{Cite web |title=The Standard Model |url=https://www-project.slac.stanford.edu/e158/StandardModel.html |url-status=live |archive-url=https://web.archive.org/web/20060620190613/http://www-project.slac.stanford.edu/e158/StandardModel.html |archive-date=June 20, 2006 |access-date=January 18, 2024 |website=[[SLAC National Accelerator Laboratory]]}}</ref> Fermions respect the [[Pauli exclusion principle]], meaning that two [[Indistinguishable particles|identical fermions]] cannot simultaneously occupy the same quantum state in the same atom.<ref>{{Cite journal |last=Eisert |first=Jens |date=January 22, 2013 |title=Pauli Principle, Reloaded |url=https://physics.aps.org/articles/v6/8 |journal=Physics |language=en |volume=6 |issue=4 |pages=8 |doi=10.1103/PhysRevLett.110.040404|pmid=25166142 |arxiv=1210.5531 }}</ref> Each fermion has a corresponding [[antiparticle]], which are particles that have corresponding properties with the exception of [[Additive inverse|opposite]] [[Charge (physics)|charges]].<ref>{{Cite web |date=January 24, 2002 |title=What is antimatter? |url=https://www.scientificamerican.com/article/what-is-antimatter-2002-01-24/ |url-status=live |archive-url=https://web.archive.org/web/20140331153524/http://www.scientificamerican.com/article/what-is-antimatter-2002-01-24 |archive-date=March 31, 2014 |access-date=January 19, 2024 |website=[[Scientific American]]}}</ref> Fermions are classified based on how they interact, which is determined by the charges they carry, into two groups: [[Quark|quarks]] and [[Lepton|leptons]]. Within each group, pairs of particles that exhibit similar physical behaviors are then grouped into [[Generation (particle physics)|generations]] (see the table). Each member of a generation has a greater mass than the corresponding particle of generations prior. Thus, there are three generations of quarks and leptons.<ref name=":1">{{cite web |title=Standard Model - ATLAS Physics Cheat Sheet |url=https://cds.cern.ch/record/2759492/files/Standard%20Model%20-%20ATLAS%20Physics%20Cheat%20Sheet.pdf |access-date=2024-01-19 |website=[[ATLAS experiment|ATLAS]] |publisher=[[CERN]]}}</ref>  As first-generation particles do not decay, they comprise all of ordinary ([[baryon]]ic) matter. Specifically, all atoms consist of electrons orbiting around the [[atomic nucleus]], ultimately constituted of up and down quarks. On the other hand, second- and third-generation charged particles decay with very short [[Half-life|half-lives]] and can only be observed in high-energy environments. Neutrinos of all generations also do not decay, and pervade the universe, but rarely interact with baryonic matter.

There are six quarks: [[up quark|up]], [[down quark|down]], [[charm quark|charm]], [[strange quark|strange]], [[top quark|top]], and [[bottom quark|bottom]].<ref name=":0" /><ref name=":1" /> Quarks carry [[color charge]], and hence interact via the [[strong interaction]]. The [[color confinement]] phenomenon results in quarks being strongly bound together such that they form color-neutral composite particles called [[hadron]]s; quarks cannot individually exist and must always bind with other quarks. Hadrons can contain either a quark-antiquark pair ([[meson]]s) or three quarks ([[baryon]]s).<ref>{{cite web |title=Color Charge and Confinement |url=https://fafnir.phyast.pitt.edu/particles/color.html |url-status=live |archive-url=https://web.archive.org/web/20020322100232/http://fafnir.phyast.pitt.edu/particles/color.html |archive-date=March 22, 2002 |access-date=January 8, 2024 |website=[[University of Pittsburgh]]}}</ref> The lightest baryons are the [[Nucleon|nucleons]]: the [[proton]] and [[neutron]]. Quarks also carry [[electric charge]] and [[weak isospin]], and thus interact with other fermions through [[electromagnetism]] and [[weak interaction]]. The six leptons consist of the [[electron]], [[electron neutrino]], [[muon]], [[muon neutrino]], [[tau (particle)|tau]], and [[tau neutrino]]. The leptons do not carry color charge, and do not respond to strong interaction. The charged leptons carry an [[electric charge]] of −1&nbsp;''[[Elementary charge|e]]'', while the three [[neutrino]]s carry zero electric charge. Thus, the neutrinos' motions are influenced by only the [[weak interaction]] and [[gravity]], making them difficult to observe.