Difference between revisions of "Heavy quarks"

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Heavy quarks are specific.
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{{Short description|Type of quark}}
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{{Redirect|Charm (physics)||Charm (disambiguation)#Science and technology}}
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{{Infobox Particle
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|bgcolour        =
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|name            = Charm quark
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|image          =[[FILE:Charm quark.svg|150px]]
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|caption        =
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|num_types      =
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|composition    = [[Elementary particle]]
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|statistics      = [[Fermionic]]
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|group          = [[Quark]]
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|generation      = Second
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|interaction = [[Strong interaction|strong]], [[Weak interaction|weak]], [[electromagnetic force]], [[gravity]]
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|particle        =
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|antiparticle    = Charm antiquark ({{SubatomicParticle|Charm antiquark}})
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|theorized      = [[Sheldon Lee Glashow|Sheldon Glashow]],<br> [[John Iliopoulos]],<br> [[Luciano Maiani]] (1970)
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|discovered      =  {{plainlist|
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*[[Burton Richter]] ''et al.'' ([[SLAC]], 1974)
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*[[Samuel C. C. Ting|Samuel Ting]] ''et al.'' ([[Brookhaven National Laboratory|BNL]], 1974)}}
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|symbol          = {{SubatomicParticle|Charm quark}}
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|mass            = {{val|1.275|+0.025|-0.035|ul=GeV/c2}}<ref name="PDG2018">
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{{cite journal
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|author=M. Tanabashi et al. (Particle Data Group)
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|title=Review of Particle Physics
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|year= 2018
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|doi=10.1103/PhysRevD.98.030001
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|volume=98
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|issue=3
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|pages=030001
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|journal=Physical Review D
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|url=http://pdglive.lbl.gov/DataBlock.action?node=Q004M
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|doi-access=free
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|bibcode=2018PhRvD..98c0001T
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}}</ref>
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|decay_time      =
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|decay_particle  = [[Strange quark]] (~95%), [[down quark]] (~5%)<ref name="hyperphysics">
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{{cite web
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|quote=The c quark has about 5% probability of decaying into a d quark instead of an s quark.
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|author=R. Nave
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|url=http://hyperphysics.phy-astr.gsu.edu/hbase/particles/qrkdec.html
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|title=Transformation of Quark Flavors by the Weak Interaction
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|access-date=2010-12-06
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}}</ref><ref name="PDG2010_CKM">
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{{cite journal
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|author=K. Nakamura ''et al.'' ([[Particle Data Group]])
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|year=2010
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|title=Review of Particles Physics: The CKM Quark-Mixing Matrix
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|url=http://pdg.lbl.gov/2010/reviews/rpp2010-rev-ckm-matrix.pdf
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|journal=[[Journal of Physics G]]
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|volume=37 |issue=75021 |page=150
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|doi=10.1088/0954-3899/37/7a/075021
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|display-authors=etal
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|bibcode=2010JPhG...37g5021N}}</ref>
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|electric_charge = +{{sfrac|2|3}} [[Elementary charge|''e'']]
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|color_charge    = Yes
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|spin            = {{sfrac|1|2}}
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|num_spin_states =
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|weak_isospin    = {{nowrap|[[Chirality (physics)|LH]]: +{{sfrac|1|2}}, [[Chirality (physics)|RH]]: 0}}
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|weak_hypercharge= {{nowrap|[[Chirality (physics)|LH]]: +{{sfrac|1|3}}, [[Chirality (physics)|RH]]: +{{sfrac|4|3}}}}
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}}
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The '''charm quark''', '''charmed quark''' or '''c quark''' (from its symbol, c) is the third most massive of all [[quark]]s, a type of [[elementary particle]]. Charm quarks are found in [[hadron]]s, which are [[subatomic particle]]s made of quarks. Examples of hadrons containing charm quarks include the [[J/ψ]] meson ({{SubatomicParticle|J/Psi}}), [[D meson]]s ({{SubatomicParticle|D}}), [[charmed Sigma baryon]]s ({{SubatomicParticle|charmed Sigma}}), and other charmed particles.
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It, along with the [[strange quark]], is part of the [[generation (particle physics)|second generation]] of matter, and has an [[electric charge]] of +{{sfrac|2|3}}&nbsp;[[elementary charge|''e'']] and a [[Quark#Mass|bare mass]] of {{val|1.275|+0.025|-0.035|ul=GeV/c2}}.<ref name="PDG2018"/> Like all [[quark]]s, the charm quark is an [[elementary particle|elementary]] [[fermion]] with [[spin (physics)|spin]] [[spin-1/2|{{sfrac|1|2}}]], and experiences all four [[fundamental interaction]]s: [[gravitation]], [[electromagnetism]], [[weak interaction]]s, and [[strong interaction]]s. The [[antiparticle]] of the charm quark is the '''charm antiquark''' (sometimes called ''anticharm quark'' or simply ''anticharm''), which differs from it only in that some of its properties have [[additive inverse|equal magnitude but opposite sign]].
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The existence of a fourth quark had been speculated by a number of authors around 1964 (for instance by [[James Bjorken]] and [[Sheldon Lee Glashow|Sheldon Glashow]]<ref>
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{{cite journal
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|author=B.J. Bjorken, S.L. Glashow
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|year=1964
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|title=Elementary particles and SU(4)
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|journal=[[Physics Letters]]
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|volume=11 |pages=255–257
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|doi=10.1016/0031-9163(64)90433-0
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|bibcode = 1964PhL....11..255B
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|issue=3 |last2=Glashow
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}}</ref>), but its prediction is usually credited to [[Sheldon Lee Glashow|Sheldon Glashow]], [[John Iliopoulos]] and [[Luciano Maiani]] in 1970 (see [[GIM mechanism]]).<ref>
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{{cite journal
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|author=S.L. Glashow, J. Iliopoulos, L. Maiani
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|year=1970
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|title=Weak Interactions with Lepton–Hadron Symmetry
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|journal=[[Physical Review D]]
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|volume=2 |pages=1285–1292
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|doi=10.1103/PhysRevD.2.1285
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|bibcode = 1970PhRvD...2.1285G
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|issue=7 |last2=Iliopoulos
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|last3=Maiani
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}}</ref> Glashow is quoted as saying, "We called our construct the 'charmed quark', for we were fascinated and pleased by the symmetry it brought to the subnuclear world."<ref>
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{{cite book
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|author=M. Riordan
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|title=The Hunting of the Quark: A True Story of Modern Physics
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|page=[https://archive.org/details/huntingofquarktr00mich/page/210 210]
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|publisher=[[Simon & Schuster]]
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|year=1987
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|isbn=978-0-671-50466-3
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|url=https://archive.org/details/huntingofquarktr00mich/page/210
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}}</ref> The first charmed particle (a particle containing a charm quark) to be discovered was the [[J/ψ meson]]. It was discovered in 1974 by a team at the [[Stanford Linear Accelerator Center]] (SLAC), led by [[Burton Richter]],<ref>
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{{cite journal
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|author=J.-E. Augustin
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|year=1974
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|title=Discovery of a Narrow Resonance in ''e''<sup>+</sup>''e''<sup>−</sup> Annihilation
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|journal=[[Physical Review Letters]]
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|volume=33 |issue=23 |page=1406
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|bibcode=1974PhRvL..33.1406A
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|doi=10.1103/PhysRevLett.33.1406
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|display-authors=etal|doi-access=free
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}}</ref> and one at the [[Brookhaven National Laboratory]] (BNL), led by [[Samuel C. C. Ting|Samuel Ting]].<ref>
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{{cite journal
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|author=J.J. Aubert
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|year=1974
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|title=Experimental Observation of a Heavy Particle ''J''
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|journal=[[Physical Review Letters]]
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|volume=33 |issue=23 |page=1404
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|bibcode=1974PhRvL..33.1404A
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|doi=10.1103/PhysRevLett.33.1404
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|display-authors=etal|doi-access=free
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}}</ref>
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The 1974 discovery of the {{SubatomicParticle|J/Psi}} (and thus the charm quark) ushered in a series of breakthroughs which are collectively known as the ''[[November Revolution (physics)|November Revolution]]''.
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== Hadrons containing charm quarks ==
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{{Main list|List of baryons|list of mesons}}
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Some of the [[hadron]]s containing charm quarks include:
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* [[D meson]]s contain a charm quark (or its [[antiparticle]]) and an [[up quark|up]] or [[down quark]].
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* {{SubatomicParticle|Strange D}} mesons contain a charm quark and a [[strange quark]].
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* There are many [[charmonium]] states, for example the {{SubatomicParticle|J/Psi}} particle. These consist of a charm quark and its antiparticle.
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* [[Charmed baryon]]s have been observed, and are named in analogy with strange baryons (e.g. {{SubatomicParticle|Charmed Lambda+}}).
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==See also==
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*[[Quark model]]
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== References ==
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{{Reflist}}
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==Further reading==
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*{{cite web
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|author=R. Nave
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|title=Quarks
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|url=http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/quark.html
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|work=[[HyperPhysics]]
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|publisher=[[Georgia State University]], Department of Physics and Astronomy
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|access-date=2008-06-29
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}}
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*{{cite book
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|author=A. Pickering
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|title=Constructing Quarks
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|pages=114–125
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|publisher=[[University of Chicago Press]]
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|year=1984
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|isbn=978-0-226-66799-7
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}}
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{{Particles}}
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{{Authority control}}
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[[Category:Quarks]]
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[[Category:Elementary particles]]

Latest revision as of 08:11, 10 May 2021

Template:Short description Template:Redirect Template:Infobox Particle

The charm quark, charmed quark or c quark (from its symbol, c) is the third most massive of all quarks, a type of elementary particle. Charm quarks are found in hadrons, which are subatomic particles made of quarks. Examples of hadrons containing charm quarks include the J/ψ meson (Template:SubatomicParticle), D mesons (Template:SubatomicParticle), charmed Sigma baryons (Template:SubatomicParticle), and other charmed particles.

It, along with the strange quark, is part of the second generation of matter, and has an electric charge of +Template:Sfrac e and a bare mass of Template:Val.<ref name="PDG2018"/> Like all quarks, the charm quark is an elementary fermion with spin [[spin-1/2|Template:Sfrac]], and experiences all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions. The antiparticle of the charm quark is the charm antiquark (sometimes called anticharm quark or simply anticharm), which differs from it only in that some of its properties have equal magnitude but opposite sign.

The existence of a fourth quark had been speculated by a number of authors around 1964 (for instance by James Bjorken and Sheldon Glashow<ref> Template:Cite journal</ref>), but its prediction is usually credited to Sheldon Glashow, John Iliopoulos and Luciano Maiani in 1970 (see GIM mechanism).<ref> Template:Cite journal</ref> Glashow is quoted as saying, "We called our construct the 'charmed quark', for we were fascinated and pleased by the symmetry it brought to the subnuclear world."<ref> Template:Cite book</ref> The first charmed particle (a particle containing a charm quark) to be discovered was the J/ψ meson. It was discovered in 1974 by a team at the Stanford Linear Accelerator Center (SLAC), led by Burton Richter,<ref> Template:Cite journal</ref> and one at the Brookhaven National Laboratory (BNL), led by Samuel Ting.<ref> Template:Cite journal</ref>

The 1974 discovery of the Template:SubatomicParticle (and thus the charm quark) ushered in a series of breakthroughs which are collectively known as the November Revolution.

Hadrons containing charm quarks

Template:Main list

Some of the hadrons containing charm quarks include:

See also

References

Template:Reflist

Further reading

Template:Particles Template:Authority control

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