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Down Quark
Down Quark
Published: 2008/07/22
Channel: cassiopeiaproject
Quarks | Standard Model Of Particle Physics
Quarks | Standard Model Of Particle Physics
Published: 2009/11/10
Channel: Best0fScience
Strange Charm: A Song about Quarks
Strange Charm: A Song about Quarks
Published: 2010/10/21
Channel: vlogbrothers
Fundamental Particles
Fundamental Particles
Published: 2014/04/30
Channel: Bozeman Science
What Are Quarks? (by Murray Gell-Mann) - Discovery Channel 100 Greatest Discoveries Physics
What Are Quarks? (by Murray Gell-Mann) - Discovery Channel 100 Greatest Discoveries Physics
Published: 2012/12/09
Channel: U3x J
What are Quarks? Sugar Edition!
What are Quarks? Sugar Edition!
Published: 2015/06/26
Channel: Physics Girl
What are Quarks? | Physics | The Fuse School
What are Quarks? | Physics | The Fuse School
Published: 2013/01/25
Channel: FuseSchool - Global Education
Quark Down - Claire (videoclipe oficial) [HD]
Quark Down - Claire (videoclipe oficial) [HD]
Published: 2012/06/23
Channel: BandaQuarkDown1
Quarks: Inside the Atom
Quarks: Inside the Atom
Published: 2007/09/21
Channel: Al Mazurek III
The Bigger the Risk the Bigger the Win - Quark Deep Space Nine Torpedo Defiant Scene
The Bigger the Risk the Bigger the Win - Quark Deep Space Nine Torpedo Defiant Scene
Published: 2014/02/05
Channel: Jeff Johnson
Higgs, Graviton, Weak Bosons, Photon, Gluon, Nuetron, Nuetrino, Proton, Electron, Up Quark, Electron
Higgs, Graviton, Weak Bosons, Photon, Gluon, Nuetron, Nuetrino, Proton, Electron, Up Quark, Electron
Published: 2014/07/20
Channel: Stargazers Nation™
Quarks and leptons for beginners
Quarks and leptons for beginners
Published: 2014/03/28
Channel: Roger Linsell
Down Quark - Blind Ellis
Down Quark - Blind Ellis
Published: 2017/04/10
Channel: Blind Ellis
What Makes up Everything?
What Makes up Everything?
Published: 2015/10/28
Channel: Randomly Researched
What is QUARK? What does QUARK mean? QUARK meaning, definition & explanation
What is QUARK? What does QUARK mean? QUARK meaning, definition & explanation
Published: 2016/08/21
Channel: The Audiopedia
QUARK DOWN - ILLUSION HORIZON (CLIPE OFICIAL) [HD]
QUARK DOWN - ILLUSION HORIZON (CLIPE OFICIAL) [HD]
Published: 2012/10/20
Channel: BandaQuarkDown1
4- Down Quark
4- Down Quark
Published: 2013/05/28
Channel: Ahmed Suleiman
The Down Quark
The Down Quark
Published: 2011/09/08
Channel: quicknuclearscience
Gravity Master 2 Custom Level - "Down Quark" Submitted by Jeff
Gravity Master 2 Custom Level - "Down Quark" Submitted by Jeff
Published: 2014/02/04
Channel: Tavros1
Out Of Sight - From Quarks To Molecules
Out Of Sight - From Quarks To Molecules
Published: 2009/09/26
Channel: Best0fScience
dOWn qUArK - URKNALL Live Footage: Cool Expansion - Big Buttinsky Osnabrück 2013-09-27
dOWn qUArK - URKNALL Live Footage: Cool Expansion - Big Buttinsky Osnabrück 2013-09-27
Published: 2013/10/05
Channel: Big Buttinsky
PARTICULARS Part 1: Down Quark
PARTICULARS Part 1: Down Quark
Published: 2015/09/24
Channel: Lady Top Hat
Down quark Meaning
Down quark Meaning
Published: 2015/04/21
Channel: SDictionary
Down Quark
Down Quark
Published: 2017/05/06
Channel: Maggie Berry
The Down Quark
The Down Quark
Published: 2010/09/29
Channel: TheVacuumEnergy
Anti-down quark Meaning
Anti-down quark Meaning
Published: 2015/04/24
Channel: SDictionary
This is so trippy. From galaxies all the way down to quarks.
This is so trippy. From galaxies all the way down to quarks.
Published: 2015/11/26
Channel: funterest
Down quark
Down quark
Published: 2016/01/22
Channel: WikiAudio
Down Quark
Down Quark
Published: 2009/07/31
Channel: angryangelhouse
Cassiopeia Project - Standard Model - 04 Down Quark
Cassiopeia Project - Standard Model - 04 Down Quark
Published: 2017/05/04
Channel: Cassiopeia Project
What does down quark mean?
What does down quark mean?
Published: 2015/03/31
Channel: What Does That Mean?
Weak Nuclear Force Beta Decay of down quark
Weak Nuclear Force Beta Decay of down quark
Published: 2009/08/27
Channel: CosmicRay137
Particulars #1: I
Particulars #1: I'm down (Quark)
Published: 2015/10/06
Channel: Robert HasAllTehSwag
PHYSIK IM THEATER: Urbausteine der Materie – die fabelhafte Welt der Quarks (24.11.2014)
PHYSIK IM THEATER: Urbausteine der Materie – die fabelhafte Welt der Quarks (24.11.2014)
Published: 2015/01/05
Channel: Uni Mainz
Chemistry - Structure
Chemistry - Structure
Published: 2014/12/28
Channel: Stargazers Nation™
Down Quark hebrew sub
Down Quark hebrew sub
Published: 2008/12/27
Channel: zemed439
Ratchet And Clank Walkthrough Ep.16 w/Angel - Your Going Down Quark!
Ratchet And Clank Walkthrough Ep.16 w/Angel - Your Going Down Quark!
Published: 2013/10/13
Channel: FearedAngel
Partículas Fundamentais: O Quark Down
Partículas Fundamentais: O Quark Down
Published: 2013/07/16
Channel: Casa das Ciências
A down quark
A down quark's effect on the atomic palate.mov
Published: 2010/06/16
Channel: cratfamwynson
QUARK DOWN - Time (cover Pink Floyd)
QUARK DOWN - Time (cover Pink Floyd)
Published: 2012/09/04
Channel: BandaQuarkDown1
Down Quark - Das Aerobicmodul 1
Down Quark - Das Aerobicmodul 1
Published: 2013/05/15
Channel: Henning Bischof
What does anti-down quark mean?
What does anti-down quark mean?
Published: 2015/09/21
Channel: What Does That Mean?
Quark Down (Studio TEASER)
Quark Down (Studio TEASER)
Published: 2012/03/11
Channel: Murilo Batera
Complicit - Down Quark (Original Mix)
Complicit - Down Quark (Original Mix)
Published: 2015/02/07
Channel: SecreTechno Recordings
Down Quarks by Sarah Perry
Down Quarks by Sarah Perry
Published: 2014/09/15
Channel: Sarah Perry
What are Quark Stars? Searching for these Exotic Objects
What are Quark Stars? Searching for these Exotic Objects
Published: 2016/07/25
Channel: Fraser Cain
Diagram 226 WOW! Protons Up Down Quarks Gluons
Diagram 226 WOW! Protons Up Down Quarks Gluons
Published: 2016/10/05
Channel: theideagirlsays
Ratchet   Clank™ 43 Taking down QUARK
Ratchet Clank™ 43 Taking down QUARK
Published: 2016/05/31
Channel: Morpheus
Quark, Strangeness & Charm
Quark, Strangeness & Charm
Published: 2015/12/12
Channel: Doktor Uzo
Quark und Co   Leben mit dem Down Syndrom GERMAN DOKU
Quark und Co Leben mit dem Down Syndrom GERMAN DOKU
Published: 2013/11/21
Channel: phoenix27121
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
  (Redirected from Down antiquark)
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Down quark
Composition Elementary particle
Statistics Fermionic
Generation First
Interactions Strong, Weak, Electromagnetic force, Gravity
Symbol
d
Antiparticle Down antiquark (
d
)
Theorized Murray Gell-Mann (1964)
George Zweig (1964)
Discovered SLAC (1968)
Mass 4.8+0.5
−0.3
 MeV/c2
[1]
Decays into Stable or Up quark + Electron + Electron antineutrino
Electric charge 1/3 e
Color charge yes
Spin 1/2
Weak isospin LH: −1/2, RH: 0
Weak hypercharge LH: 1/3, RH: −2/3

The down quark or d quark (symbol: d) is the second-lightest of all quarks, a type of elementary particle, and a major constituent of matter. Together with the up quark, it forms the neutrons (one up quark, two down quarks) and protons (two up quarks, one down quark) of atomic nuclei. It is part of the first generation of matter, has an electric charge of −1/3 e and a bare mass of 4.8+0.5
−0.3
 MeV/c2
.[1] Like all quarks, the down quark is an elementary fermion with spin 1/2, and experiences all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions. The antiparticle of the down quark is the down antiquark (sometimes called antidown quark or simply antidown), which differs from it only in that some of its properties have equal magnitude but opposite sign.

Its existence (along with that of the up and strange quarks) was postulated in 1964 by Murray Gell-Mann and George Zweig to explain the Eightfold Way classification scheme of hadrons. The down quark was first observed by experiments at the Stanford Linear Accelerator Center in 1968.

History[edit]

In the beginnings of particle physics (first half of the 20th century), hadrons such as protons, neutrons, and pions were thought to be elementary particles. However, as new hadrons were discovered, the 'particle zoo' grew from a few particles in the early 1930s and 1940s to several dozens of them in the 1950s. The relationships between each of them was unclear until 1961, when Murray Gell-Mann[2] and Yuval Ne'eman[3] (independently of each other) proposed a hadron classification scheme called the Eightfold Way, or in more technical terms, SU(3) flavor symmetry.

This classification scheme organized the hadrons into isospin multiplets, but the physical basis behind it was still unclear. In 1964, Gell-Mann[4] and George Zweig[5][6] (independently of each other) proposed the quark model, then consisting only of up, down, and strange quarks.[7] However, while the quark model explained the Eightfold Way, no direct evidence of the existence of quarks was found until 1968 at the Stanford Linear Accelerator Center.[8][9] Deep inelastic scattering experiments indicated that protons had substructure, and that protons made of three more-fundamental particles explained the data (thus confirming the quark model).[10]

At first people were reluctant to identify the three-bodies as quarks, instead preferring Richard Feynman's parton description,[11][12][13] but over time the quark theory became accepted (see November Revolution).[14]

Mass[edit]

Despite being extremely common, the bare mass of the down quark is not well determined, but probably lies between 4.5 and 5.3MeV/c2.[1] Lattice QCD calculations give a more precise value: 4.79±0.16 MeV/c2.[15]

When found in mesons (particles made of one quark and one antiquark) or baryons (particles made of three quarks), the 'effective mass' (or 'dressed' mass) of quarks becomes greater because of the binding energy caused by the gluon field between quarks (see mass–energy equivalence). For example, the effective mass of down quarks in a proton is around 330 MeV/c2. Because the bare mass of down quarks is so small, it cannot be straightforwardly calculated because relativistic effects have to be taken into account.

See also[edit]

References[edit]

  1. ^ a b c J. Beringer (Particle Data Group); et al. (2013). "PDGLive Particle Summary 'Quarks (u, d, s, c, b, t, b′, t′, Free)'" (PDF). Particle Data Group. Retrieved 2013-07-23. 
  2. ^ M. Gell-Mann (2000) [1964]. "The Eightfold Way: A theory of strong interaction symmetry". In M. Gell-Mann, Y. Ne'eman. The Eightfold Way. Westview Press. p. 11. ISBN 0-7382-0299-1. 
    Original: M. Gell-Mann (1961). "The Eightfold Way: A theory of strong interaction symmetry". Synchrotron Laboratory Report CTSL-20. California Institute of Technology. 
  3. ^ Y. Ne'eman (2000) [1964]. "Derivation of strong interactions from gauge invariance". In M. Gell-Mann, Y. Ne'eman. The Eightfold Way. Westview Press. ISBN 0-7382-0299-1. 
    Original Y. Ne'eman (1961). "Derivation of strong interactions from gauge invariance". Nuclear Physics. 26 (2): 222. Bibcode:1961NucPh..26..222N. doi:10.1016/0029-5582(61)90134-1. 
  4. ^ M. Gell-Mann (1964). "A Schematic Model of Baryons and Mesons". Physics Letters. 8 (3): 214–215. Bibcode:1964PhL.....8..214G. doi:10.1016/S0031-9163(64)92001-3. 
  5. ^ G. Zweig (1964). "An SU(3) Model for Strong Interaction Symmetry and its Breaking". CERN Report No.8181/Th 8419. 
  6. ^ G. Zweig (1964). "An SU(3) Model for Strong Interaction Symmetry and its Breaking: II". CERN Report No.8419/Th 8412. 
  7. ^ B. Carithers, P. Grannis (1995). "Discovery of the Top Quark" (PDF). Beam Line. SLAC. 25 (3): 4–16. Retrieved 2008-09-23. 
  8. ^ E. D. Bloom; Coward, D.; Destaebler, H.; Drees, J.; Miller, G.; Mo, L.; Taylor, R.; Breidenbach, M.; et al. (1969). "High-Energy Inelastic ep Scattering at 6° and 10°". Physical Review Letters. 23 (16): 930–934. Bibcode:1969PhRvL..23..930B. doi:10.1103/PhysRevLett.23.930. 
  9. ^ M. Breidenbach; Friedman, J.; Kendall, H.; Bloom, E.; Coward, D.; Destaebler, H.; Drees, J.; Mo, L.; Taylor, R.; et al. (1969). "Observed Behavior of Highly Inelastic Electron–Proton Scattering". Physical Review Letters. 23 (16): 935–939. Bibcode:1969PhRvL..23..935B. doi:10.1103/PhysRevLett.23.935. 
  10. ^ J. I. Friedman. "The Road to the Nobel Prize". Hue University. Retrieved 2008-09-29. 
  11. ^ R. P. Feynman (1969). "Very High-Energy Collisions of Hadrons". Physical Review Letters. 23 (24): 1415–1417. Bibcode:1969PhRvL..23.1415F. doi:10.1103/PhysRevLett.23.1415. 
  12. ^ S. Kretzer; Lai, H.; Olness, Fredrick; Tung, W.; et al. (2004). "CTEQ6 Parton Distributions with Heavy Quark Mass Effects". Physical Review D. 69 (11): 114005. Bibcode:2004PhRvD..69k4005K. arXiv:hep-ph/0307022Freely accessible. doi:10.1103/PhysRevD.69.114005. 
  13. ^ D. J. Griffiths (1987). Introduction to Elementary Particles. John Wiley & Sons. p. 42. ISBN 0-471-60386-4. 
  14. ^ M. E. Peskin, D. V. Schroeder (1995). An introduction to quantum field theory. Addison–Wesley. p. 556. ISBN 0-201-50397-2. 
  15. ^ Cho, Adrian (April 2010). "Mass of the Common Quark Finally Nailed Down". Science Magazine. 

Further reading[edit]

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