| 词条 | Charm quark |
| 释义 |
|bgcolour = |name = Charm quark |image = |caption = |num_types = |composition = Elementary particle |statistics = Fermionic |group = Quark |generation = Second |interaction = Strong, weak, electromagnetic, gravity |particle = |antiparticle = Charm antiquark ({{SubatomicParticle|Charm antiquark}}) |theorized = Sheldon Glashow, John Iliopoulos, Luciano Maiani (1970) |discovered = {{plainlist|
|symbol = {{SubatomicParticle|Charm quark}} |mass = {{val|1.275|+0.025|-0.035|ul=GeV/c2}}[1] |decay_time = |decay_particle = Strange quark (~95%), down quark (~5%)[2][3] |electric_charge = +{{sfrac|2|3}} e |color_charge = Yes |spin = {{sfrac|1|2}} |num_spin_states = |weak_isospin = {{nowrap|LH: +{{sfrac|1|2}}, RH: 0}} |weak_hypercharge= {{nowrap|LH: +{{sfrac|1|3}}, RH: +{{sfrac|4|3}}}} }} 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 ({{SubatomicParticle|J/Psi}}), D mesons ({{SubatomicParticle|D}}), charmed Sigma baryons ({{SubatomicParticle|charmed Sigma}}), and other charmed particles. It, along with the strange quark is part of the second generation of matter, and has an electric charge of +{{sfrac|2|3}} e and a bare mass of {{val|1.275|+0.025|-0.035|ul=GeV/c2}}.[1] Like all quarks, the charm quark is an elementary fermion with spin {{sfrac|1|2}}, 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[4]), but its prediction is usually credited to Sheldon Glashow, John Iliopoulos and Luciano Maiani in 1970 (see GIM mechanism).[5] The first charmed particle (a particle containing a charm quark) to be discovered was the J/ψ meson. It was discovered by a team at the Stanford Linear Accelerator Center (SLAC), led by Burton Richter,[6] and one at the Brookhaven National Laboratory (BNL), led by Samuel Ting.[7] 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. Hadrons containing charm quarks{{Main|List of baryons|list of mesons}}Some of the hadrons containing charm quarks include:
See also
Notes1. ^1 {{cite journal |author=M. Tanabashi et al. (Particle Data Group) |title=Review of Particle Physics |year= 2018 |doi=10.1103/PhysRevD.98.030001 |volume=98 |issue=3 |pages=030001 |journal=Physical Review D |url=http://pdglive.lbl.gov/DataBlock.action?node=Q004M }} 2. ^{{cite web |quote=The c quark has about 5% probability of decaying into a d quark instead of an s quark. |author=R. Nave |url=http://hyperphysics.phy-astr.gsu.edu/hbase/particles/qrkdec.html |title=Transformation of Quark Flavors by the Weak Interaction |accessdate=2010-12-06}} 3. ^{{cite journal |author=K. Nakamura et al. (Particle Data Group) |year=2010 |title=Review of Particles Physics: The CKM Quark-Mixing Matrix |url=http://pdg.lbl.gov/2010/reviews/rpp2010-rev-ckm-matrix.pdf |journal=Journal of Physics G |volume=37 |issue=75021 |page=150 |doi=10.1088/0954-3899/37/7a/075021|author-separator= |displayauthors=etal |bibcode=2010JPhG...37g5021N}} 4. ^{{cite journal |author=B.J. Bjorken, S.L. Glashow |year=1964 |title=Elementary particles and SU(4) |journal=Physics Letters |volume=11 |pages=255–257 |doi=10.1016/0031-9163(64)90433-0|bibcode = 1964PhL....11..255B |issue=3 |last2=Glashow }} 5. ^{{cite journal |author=S.L. Glashow, J. Iliopoulos, L. Maiani |year=1970 |title=Weak Interactions with Lepton–Hadron Symmetry |journal=Physical Review D |volume=2 |pages=1285–1292 |doi=10.1103/PhysRevD.2.1285|bibcode = 1970PhRvD...2.1285G |issue=7 |last2=Iliopoulos |last3=Maiani }} 6. ^{{cite journal |author=J.-E. Augustin |year=1974 |title=Discovery of a Narrow Resonance in e+e− Annihilation |journal=Physical Review Letters |volume=33 |issue=23 |page=1406 |bibcode=1974PhRvL..33.1406A |doi=10.1103/PhysRevLett.33.1406|display-authors=etal}} 7. ^{{cite journal |author=J.J. Aubert |year=1974 |title=Experimental Observation of a Heavy Particle J |journal=Physical Review Letters |volume=33 |issue=23 |page=1404 |bibcode=1974PhRvL..33.1404A |doi=10.1103/PhysRevLett.33.1404|display-authors=etal}} Further reading
|author=R. Nave |title=Quarks |url=http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/quark.html |work=HyperPhysics |publisher=Georgia State University, Department of Physics and Astronomy |year= |accessdate=2008-06-29 }}
|author=A. Pickering |title=Constructing Quarks |pages=114–125 |publisher=University of Chicago Press |year=1984 |isbn=978-0-226-66799-7 }}{{Particles}} 2 : Quarks|Elementary particles |
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