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| In [[particle physics]], '''quarkonium''' (from [[quark]] + [[onium]], pl. '''quarkonia''') designates a flavorless [[meson]] whose constituents are a [[quark]] and its own antiquark. Examples of quarkonia are the [[J/Psi meson|J/ψ meson]] (an example of '''charmonium''', {{SubatomicParticle|Charm quark|link=yes}}{{SubatomicParticle|Charm antiquark|link=yes}}) and the [[Upsilon particle|{{SubatomicParticle|Upsilon}} meson]] ('''bottomonium''', {{SubatomicParticle|Bottom quark|link=yes}}{{SubatomicParticle|Bottom antiquark|link=yes}}). Because of the high mass of the [[top quark]], '''toponium''' does not exist, since the top quark decays through the [[electroweak interaction]] before a bound state can form. Usually quarkonium refers only to charmonium and bottomonium, and not to any of the lighter quark–antiquark states. This usage is because the lighter quarks ([[up quark|up]], [[down quark|down]], and [[strange quark|strange]]) are much less massive than the heavier quarks, and so the physical states actually seen in experiments are quantum mechanical mixtures of the light quark states. The much larger mass differences between the [[charm quark|charm]] and [[bottom quark|bottom]] quarks and the lighter [[quark]]s results in states that are well defined in terms of a quark–antiquark pair of a given flavor.
| | She is known by the title of Myrtle Shryock. For a while she's been in South Dakota. It's not a typical factor but what she likes performing is base leaping and now she is trying to earn cash with it. My day occupation is a meter reader.<br><br>Here is my webpage; [http://Www.Buzzbit.net/user/VTrue over the counter std test] |
| | |
| ==Charmonium states==
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| {{See also|J/ψ meson}}
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| In the following table, the same particle can be named with the [[spectroscopic notation]] or with its mass. In some cases excitation series are used: Ψ' is the first excitation of Ψ (for historical reasons, this one is called ''J/ψ'' particle); Ψ" is a second excitation, and so on. That is, names in the same cell are synonymous.
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| | |
| Some of the states are predicted, but have not been identified; others are unconfirmed. The quantum numbers of the [[X(3872)]] particle have been measured recently by the LHCb experiment at CERN<ref>
| |
| {{cite journal
| |
| |date=February 2013
| |
| |title=Determination of the X(3872) meson quantum numbers
| |
| |url=http://inspirehep.net/record/1221245?ln=en
| |
| |bibcode=2013arXiv1302.6269L
| |
| |author1=LHCb collaboration
| |
| |last2=Aaij
| |
| |first2=R.
| |
| |last3=Abellan Beteta
| |
| |first3=C.
| |
| |last4=Adeva
| |
| |first4=B.
| |
| |last5=Adinolfi
| |
| |first5=M.
| |
| |last6=Adrover
| |
| |first6=C.
| |
| |last7=Affolder
| |
| |first7=A.
| |
| |last8=Ajaltouni
| |
| |first8=Z.
| |
| |last9=Albrecht
| |
| |first9=J.
| |
| |displayauthors=8
| |
| |volume=1302
| |
| |pages=6269
| |
| |arxiv=1302.6269
| |
| |doi=10.1103/PhysRevLett.110.222001
| |
| |journal=Physical Review Letters
| |
| |issue=22
| |
| }}</ref>
| |
| . This measurement shed some light on its identity, excluding the third option among the three envised, which are :
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| * a candidate for the 1<sup>1</sup>D<sub>2</sub> state;
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| * a charmonium hybrid state;
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| * a <math>D^0\bar D^{*0}</math> molecule.
| |
| | |
| In 2005, the [[BaBar experiment]] announced the discovery of a new state: [[Y(4260)]].<ref>
| |
| {{cite web
| |
| |date=6 July 2005
| |
| |title=A new particle discovered by BaBar experiment
| |
| |url=http://www.infn.it/news/newsen.php?id=351
| |
| |publisher=[[Istituto Nazionale di Fisica Nucleare]]
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| |accessdate=2010-03-06
| |
| }}</ref><ref>
| |
| {{cite journal
| |
| |author=B. Aubert ''et al.'' ([[BaBar experiment|BaBar Collaboration]])
| |
| |year=2005
| |
| |title=Observation of a broad structure in the π<sup>+</sup>π<sup>−</sup>J/ψ mass spectrum around {{val|4.26|u=GeV/c2}}
| |
| |journal=[[Physical Review Letters]]
| |
| |volume=95 |issue=14 |pages=142001
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| |arxiv=hep-ex/0506081
| |
| |bibcode = 2005PhRvL..95n2001A
| |
| |doi=10.1103/PhysRevLett.95.142001
| |
| }}</ref> [[CLEO (particle detector)|CLEO]] and [[Belle experiment|Belle]] have since corroborated these observations. At first, Y(4260) was thought to be a charmonium state, but the evidence suggests more exotic explanations, such as a D "molecule", a 4-quark construct, or a hybrid [[meson]].
| |
| | |
| {| class="wikitable"
| |
| |-
| |
| ! width="40px" | [[Term symbol]] {{nowrap|''n''<sup>2''S'' + 1</sup>''L''<sub>''J''</sub>}}
| |
| ! width="40px" | ''[[Isospin|I]]<sup>[[G-parity|G]]</sup>''(''[[Angular momentum#Angular momentum in quantum mechanics|J]]<sup>[[Parity (physics)|P]][[C-parity|C]]</sup>'')
| |
| ! width="200px" | Particle
| |
| ! mass (MeV/c<sup>2</sup>) [http://pdglive.lbl.gov/listing.brl?fsizein=1&group=MXXX025]
| |
| |-
| |
| | 1<sup>1</sup>S<sub>0</sub>
| |
| | 0<sup>+</sup>(0<sup>−+</sup>)
| |
| | [[eta-c particle|''η<sub>c</sub>'']](1''S'')
| |
| | {{val|2980.3|1.2}}
| |
| |-
| |
| | 1<sup>3</sup>S<sub>1</sub>
| |
| | 0<sup>−</sup>(1<sup>−−</sup>)
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| | [[J/Psi particle|''J/ψ'']](1''S'')
| |
| | {{val|3096.916|0.011}}
| |
| |-
| |
| | 1<sup>1</sup>P<sub>1</sub>
| |
| | 0<sup>−</sup>(1<sup>+−</sup>)
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| | [[h-c particle|''h<sub>c</sub>'']](1''P'')
| |
| | {{val|3525.93|0.27}}
| |
| |-
| |
| | 1<sup>3</sup>P<sub>0</sub>
| |
| | 0<sup>+</sup>(0<sup>++</sup>)
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| | [[chi-c particle|''χ''<sub>''c''0</sub>]](1''P'')
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| | {{val|3414.75|0.31}}
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| |-
| |
| | 1<sup>3</sup>P<sub>1</sub>
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| | 0<sup>+</sup>(1<sup>++</sup>)
| |
| | ''χ''<sub>''c''1</sub>(1''P'')
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| | {{val|3510.66|0.07}}
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| |-
| |
| | 1<sup>3</sup>P<sub>2</sub>
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| | 0<sup>+</sup>(2<sup>++</sup>)
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| | ''χ''<sub>''c''2</sub>(1''P'')
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| | {{val|3556.20|0.09}}
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| |-
| |
| | 2<sup>1</sup>S<sub>0</sub>
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| | 0<sup>+</sup>(0<sup>−+</sup>)
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| | ''η<sub>c</sub>''(2''S''), or ''{{SubatomicParticle|Charmed eta prime}}''
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| | {{val|3637|4}}
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| |-
| |
| | 2<sup>3</sup>S<sub>1</sub>
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| | 0<sup>−</sup>(1<sup>−−</sup>)
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| | ''ψ''(3686)
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| | {{val|3686.09|0.04}}
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| |-
| |
| | 1<sup>1</sup>D<sub>2</sub>
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| | 0<sup>+</sup>(2<sup>−+</sup>)
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| | ''η''<sub>''c''2</sub>(1''D'')<sup>[[#note3|†]]</sup>
| |
| |
| |
| |-
| |
| | 1<sup>3</sup>D<sub>1</sub>
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| | 0<sup>−</sup>(1<sup>−−</sup>)
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| | ''ψ''(3770)
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| | {{val|3772.92|0.35}}
| |
| |-
| |
| | 1<sup>3</sup>D<sub>2</sub>
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| | 0<sup>−</sup>(2<sup>−−</sup>)
| |
| | ''ψ''<sub>2</sub>(1''D'')
| |
| | align="center" |
| |
| |-
| |
| | 1<sup>3</sup>D<sub>3</sub>
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| | 0<sup>−</sup>(3<sup>−−</sup>)
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| | ''ψ''<sub>3</sub>(1''D'')<sup>[[#note3|†]]</sup>
| |
| | align="center" |
| |
| |-
| |
| | 2<sup>1</sup>P<sub>1</sub>
| |
| | 0<sup>−</sup>(1<sup>+−</sup>)
| |
| | ''h<sub>c</sub>''(2''P'')<sup>[[#note3|†]]</sup>
| |
| | align="center" |
| |
| |-
| |
| | 2<sup>3</sup>P<sub>0</sub>
| |
| | 0<sup>+</sup>(0<sup>++</sup>)
| |
| | ''χ''<sub>''c''0</sub>(2''P'')<sup>[[#note3|†]]</sup>
| |
| | align="center" |
| |
| |-
| |
| | 2<sup>3</sup>P<sub>1</sub>
| |
| | 0<sup>+</sup>(1<sup>++</sup>)
| |
| | ''χ''<sub>''c''1</sub>(2''P'')<sup>[[#note3|†]]</sup>
| |
| | align="center" |
| |
| |-
| |
| | 2<sup>3</sup>P<sub>2</sub>
| |
| | 0<sup>+</sup>(2<sup>++</sup>)
| |
| | ''χ''<sub>''c''2</sub>(2''P'')<sup>[[#note3|†]]</sup>
| |
| | align="center" |
| |
| |-
| |
| | ?<sup>?</sup>?<sub>?</sub>
| |
| | 1<sup>++</sup>[[#note1|†]]
| |
| | ''X''(3872)
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| | {{val|3872.2|0.8}}
| |
| |-
| |
| | ?<sup>?</sup>?<sub>?</sub>
| |
| | ?<sup>?</sup>(1<sup>−−</sup>)
| |
| | ''Y''(4260)
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| | {{val|4263|+8|-9}}
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| |}
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| <small>Notes:</small>
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| :<small><span id="note1"><sup>*</sup></span> Needs confirmation.</small>
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| :<small><span id="note3"><sup>†</sup></span> Predicted, but not yet identified.</small>
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| :<small><span id="note2"><sup>†</sup></span> Interpretation as a 1<sup>−−</sup> charmonium state not favored.</small>
| |
| | |
| ==Bottomonium states==
| |
| {{See also |Upsilon meson}}
| |
| In the following table, the same particle can be named with the spectroscopic notation or with its mass.
| |
| | |
| Some of the states are predicted, but have not been identified; others are unconfirmed.
| |
| | |
| {| class="wikitable"
| |
| |-
| |
| ! width="40px" | [[Term symbol]] n<sup>2S+1</sup>L<sub>J</sub>
| |
| ! width="40px" | ''[[Isospin|I]]<sup>[[G-parity|G]]</sup>''(''[[Angular momentum#Angular momentum in quantum_mechanics|J]]<sup>[[Parity (physics)|P]][[C-parity|C]]</sup>'')
| |
| ! width="200px" | Particle
| |
| !| mass (MeV/c<sup>2</sup>)[http://pdglive.lbl.gov/listing.brl?fsizein=1&exp=Y&group=MXXX030]
| |
| |-
| |
| || 1<sup>1</sup>S<sub>0</sub>
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| || 0<sup>+</sup>(0<sup>−+</sup>)
| |
| || [[eta-b particle|''η<sub>b</sub>'']](1''S'')
| |
| || {{val|9390.9|2.8}}
| |
| |-
| |
| || 1<sup>3</sup>S<sub>1</sub>
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| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || [[Upsilon particle|''Υ'']](1''S'')
| |
| || {{val|9460.30|0.26}}
| |
| |-
| |
| || 1<sup>1</sup>P<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>+−</sup>)
| |
| || [[h-b particle|''h<sub>b</sub>'']](1''P'')
| |
| ||
| |
| |-
| |
| || 1<sup>3</sup>P<sub>0</sub>
| |
| || 0<sup>+</sup>(0<sup>++</sup>)
| |
| || [[chi-b particle|''χ''<sub>''b''0</sub>]](1''P'')
| |
| || {{val|9859.44|0.52}}
| |
| |-
| |
| || 1<sup>3</sup>P<sub>1</sub>
| |
| || 0<sup>+</sup>(1<sup>++</sup>)
| |
| || ''χ''<sub>''b''1</sub>(1''P'')
| |
| || {{val|9892.76|0.40}}
| |
| |-
| |
| || 1<sup>3</sup>P<sub>2</sub>
| |
| || 0<sup>+</sup>(2<sup>++</sup>)
| |
| || ''χ''<sub>''b''2</sub>(1''P'')
| |
| || {{val|9912.21|0.40}}
| |
| |-
| |
| || 2<sup>1</sup>S<sub>0</sub>
| |
| || 0<sup>+</sup>(0<sup>−+</sup>)
| |
| || ''η<sub>b</sub>''(2''S'')
| |
| ||
| |
| |-
| |
| || 2<sup>3</sup>S<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || ''Υ''(2''S'')
| |
| || {{val|10023.26|0.31}}
| |
| |-
| |
| || 1<sup>1</sup>D<sub>2</sub>
| |
| || 0<sup>+</sup>(2<sup>−+</sup>)
| |
| || ''η''<sub>''b''2</sub>(1''D'')<sup>
| |
| ||
| |
| |-
| |
| || 1<sup>3</sup>D<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || ''Υ''(1D)
| |
| ||
| |
| |-
| |
| || 1<sup>3</sup>D<sub>2</sub>
| |
| || 0<sup>−</sup>(2<sup>−−</sup>)
| |
| || ''Υ''<sub>2</sub>(1''D'')
| |
| || {{val|10161.1|1.7}}
| |
| |-
| |
| || 1<sup>3</sup>D<sub>3</sub>
| |
| || 0<sup>−</sup>(3<sup>−−</sup>)
| |
| || ''Υ''<sub>3</sub>(1''D'')
| |
| ||
| |
| |-
| |
| || 2<sup>1</sup>P<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>+−</sup>)
| |
| || ''h<sub>b</sub>''(2''P'')
| |
| ||
| |
| |-
| |
| || 2<sup>3</sup>P<sub>0</sub>
| |
| || 0<sup>+</sup>(0<sup>++</sup>)
| |
| || ''χ''<sub>''b''0</sub>(2''P'')
| |
| || {{val|10232.5|0.6}}
| |
| |-
| |
| || 2<sup>3</sup>P<sub>1</sub>
| |
| || 0<sup>+</sup>(1<sup>++</sup>)
| |
| || ''χ''<sub>''b''1</sub>(2''P'')
| |
| || {{val|10255.46|0.55}}
| |
| |-
| |
| || 2<sup>3</sup>P<sub>2</sub>
| |
| || 0<sup>+</sup>(2<sup>++</sup>)
| |
| || ''χ''<sub>''b''2</sub>(2''P'')
| |
| || {{val|10268.65|0.55}}
| |
| |-
| |
| || 3<sup>3</sup>S<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || ''Υ''(3''S'')
| |
| || {{val|10355.2|0.5}}
| |
| |-
| |
| || 3<sup>3</sup>P<sub>J</sub>
| |
| || 0<sup>+</sup>(J<sup>++</sup>)
| |
| || ''χ''<sub>''b''</sub>(3''P'')
| |
| || {{val|10530|5}} (stat.) ± 9 (syst.)<ref name="arxivchib3p"/>
| |
| |-
| |
| || 4<sup>3</sup>S<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || ''Υ''(4''S'') or ''Υ''(10580)
| |
| || {{val|10579.4|1.2}}
| |
| |-
| |
| || 5<sup>3</sup>S<sub>1</sub>
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| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || ''Υ''(10860)
| |
| || {{val|10865|8}}
| |
| |-
| |
| || 6<sup>3</sup>S<sub>1</sub>
| |
| || 0<sup>−</sup>(1<sup>−−</sup>)
| |
| || ''Υ''(11020)
| |
| || {{val|11019|8}}
| |
| |}
| |
| | |
| <small>'''Notes''':</small>
| |
| :<small><span id="1"><sup>*</sup></span> Preliminary results. Confirmation needed.</small>
| |
| | |
| The χ<sub>b</sub> (3P) state was the first particle discovered in the [[Large Hadron Collider]]. The article about this discovery was first submitted to [[arXiv]] on 21 December 2011.<ref name="arxivchib3p">
| |
| {{cite arxiv
| |
| |author=[[ATLAS Collaboration]]
| |
| |year=2012
| |
| |title=Observation of a new {{Physics particle|χ|BR=b}} state in radiative transitions to {{Subatomic particle|Upsilon}}(1S) and {{Subatomic particle|Upsilon}}(2S) at ATLAS
| |
| |class=hep-ex
| |
| |eprint=1112.5154
| |
| |version=v4
| |
| }}</ref><ref>
| |
| {{cite news
| |
| |url=http://www.bbc.co.uk/news/science-environment-16301908
| |
| |title=LHC reports discovery of its first new particle
| |
| |author=Jonathan Amos
| |
| |publisher=[[BBC]]
| |
| |date=2011-12-22
| |
| }}</ref> On April 2012, [[D0 experiment|Tevatron's DØ experiment]] confirms the result in a paper published in ''[[Phys. Rev. D]]''.<ref>''[http://www.symmetrymagazine.org/breaking/2012/04/09/tevatron-experiment-confirms-lhc-discovery-of-chi-b-p3-particle/ Tevatron experiment confirms LHC discovery of Chi-b (P3) particle]''</ref><ref>''[http://www-d0.fnal.gov/Run2Physics/WWW/results/final/B/B12A/B12A.pdf Observation of a narrow mass state decaying into Υ(1S) + γ in pp collisions at 1.96 TeV]''</ref>
| |
| | |
| ==QCD and quarkonia==
| |
| The computation of the properties of [[meson]]s in [[Quantum chromodynamics]] (QCD) is a fully non-perturbative one. As a result, the only general method available is a direct computation using [[lattice QCD]] (LQCD) techniques. However, other techniques are effective for heavy quarkonia as well.
| |
| | |
| The light quarks in a meson move at [[special relativity|relativistic]] speeds, since the mass of the bound state is much larger than the mass of the quark. However, the speed of the charm and the bottom quarks in their respective quarkonia is sufficiently smaller, so that relativistic effects affect these states much less. It is estimated that the speed, '''v''', is roughly 0.3 times the speed of light for charmonia and roughly 0.1 times the speed of light for bottomonia. The computation can then be approximated by an expansion in powers of '''v/c''' and '''v<sup>2</sup>/c<sup>2</sup>'''. This technique is called [[non-relativistic QCD]] (NRQCD).
| |
| | |
| [[Non-relativistic QCD|NRQCD]] has also been quantized as a [[lattice gauge theory]], which provides another technique for LQCD calculations to use. Good agreement with the bottomonium masses has been found, and this provides one of the best non-perturbative tests of LQCD. For charmonium masses the agreement is not as good, but the LQCD community is actively working on improving their techniques. Work is also being done on calculations of such properties as widths of quarkonia states and transition rates between the states.
| |
| | |
| An early, but still effective, technique uses models of the ''effective'' potential to calculate masses of quarkonia states. In this technique, one uses the fact that the motion of the quarks that comprise the quarkonium state is non-relativistic to assume that they move in a static potential, much like non-relativistic models of the hydrogen atom. One of the most popular potential models is the so-called ''Cornell potential''
| |
| | |
| :<math>V(r) = -\frac{a}{r} + br</math><ref>{{cite journal | author1=Hee Sok Chung | author2=Jungil Lee | author3=Daekyoung Kang | title=Cornell Potential Parameters for S-wave Heavy Quarkonia | doi=10.3938/jkps.52.1151 | year=2008 | journal=Journal of the Korean Physical Society | volume=52 | issue=4 | pages=1151 | arxiv=0803.3116 |bibcode = 2008JKPS...52.1151C }}</ref>
| |
| | |
| where <math>r</math> is the effective radius of the quarkonium state, <math>a</math> and <math>b</math> are parameters. This potential has two parts. The first part, <math>a/r</math> corresponds to the potential induced by one-gluon exchange between the quark and its anti-quark, and is known as the ''Coulombic'' part of the potential, since its <math>1/r</math> form is identical to the well-known Coulombic potential induced by the electromagnetic force. The second part, <math>br</math>, is known as the ''confinement'' part of the potential, and parameterizes the poorly understood non-perturbative effects of QCD. Generally, when using this approach, a convenient form for the wave function of the quarks is taken, and then <math>a</math> and <math>b</math> are determined by fitting the results of the calculations to the masses of well-measured quarkonium states. Relativistic and other effects can be incorporated into this approach by adding extra terms to the potential, much in the same way that they are for the hydrogen atom in non-relativistic quantum mechanics. This approach has no good theoretical motivation, but is popular because it allows for accurate predictions of quarkonia parameters without a lengthy lattice computation, and provides a separation between the short-distance ''Coulombic'' effects and the long-distance ''confinement'' effects that can be useful in understanding the quark/anti-quark force generated by QCD.
| |
| | |
| Quarkonia have been suggested as a diagnostic tool of the formation of the [[quark-gluon plasma]]: both disappearance and enhancement of their formation depending on the yield of heavy quarks in plasma can occur.
| |
| | |
| ==See also==
| |
| *[[Onium]]
| |
| *[[OZI Rule]]
| |
| *[[J/ψ meson]]
| |
| *[[Phi meson]]
| |
| *[[Upsilon meson]]
| |
| *[[Theta meson]]
| |
| *[[Non-relativistic QCD]]
| |
| *[[Lattice QCD]]
| |
| *[[Quantum chromodynamics]]
| |
| | |
| ==References==
| |
| {{Reflist}}
| |
| {{particles}}
| |
| | |
| [[Category:Mesons]]
| |
| [[Category:Onium]]
| |