Play Video
1
Down Quark
Down Quark
::2008/07/22::
Play Video
2
QUARK DOWN - ILLUSION HORIZON (CLIPE OFICIAL) [HD]
QUARK DOWN - ILLUSION HORIZON (CLIPE OFICIAL) [HD]
::2012/10/20::
Play Video
3
DOWN QUARK 2012-10-12 live @ Big Buttinsky
DOWN QUARK 2012-10-12 live @ Big Buttinsky
::2012/10/22::
Play Video
4
Quarks | Standard Model Of Particle Physics
Quarks | Standard Model Of Particle Physics
::2009/11/10::
Play Video
5
Strange Charm: A Song about Quarks
Strange Charm: A Song about Quarks
::2010/10/20::
Play Video
6
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
::2012/12/09::
Play Video
7
Ratchet And Clank Walkthrough Ep.16 w/Angel - Your Going Down Quark!
Ratchet And Clank Walkthrough Ep.16 w/Angel - Your Going Down Quark!
::2013/10/13::
Play Video
8
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
::2013/10/04::
Play Video
9
The Down Quark
The Down Quark
::2010/09/29::
Play Video
10
The Down Quark
The Down Quark
::2011/09/08::
Play Video
11
Upside Down Quark - Cortster12 Original
Upside Down Quark - Cortster12 Original
::2012/12/18::
Play Video
12
Down Quark hebrew sub
Down Quark hebrew sub
::2008/12/27::
Play Video
13
Down Quark - Late Night Music (Demo)
Down Quark - Late Night Music (Demo)
::2012/10/06::
Play Video
14
Down Quark - Das Aerobicmodul 1
Down Quark - Das Aerobicmodul 1
::2013/05/15::
Play Video
15
Gravity Master 2 Custom Level - "Down Quark" Submitted by Jeff
Gravity Master 2 Custom Level - "Down Quark" Submitted by Jeff
::2014/02/04::
Play Video
16
Quark Down - Claire (videoclipe oficial) [HD]
Quark Down - Claire (videoclipe oficial) [HD]
::2012/06/22::
Play Video
17
Weak Nuclear Force Beta Decay of down quark
Weak Nuclear Force Beta Decay of down quark
::2009/08/27::
Play Video
18
Out Of Sight - From Quarks To Molecules
Out Of Sight - From Quarks To Molecules
::2009/09/26::
Play Video
19
Protons and neutrons are made of Quarks
Protons and neutrons are made of Quarks
::2011/07/19::
Play Video
20
Down Quark
Down Quark
::2009/07/31::
Play Video
21
Down`t Quark im Efeu
Down`t Quark im Efeu
::2011/08/31::
Play Video
22
Partículas Fundamentais: O Quark Down
Partículas Fundamentais: O Quark Down
::2013/07/16::
Play Video
23
DARK QUARK
DARK QUARK
::2014/01/22::
Play Video
24
08 CHARMED QUARK
08 CHARMED QUARK
::2010/04/29::
Play Video
25
Nuclear Fusion Quark Balloon Protons 2 NEWtron Bunny Gluon e+ neutrinos
Nuclear Fusion Quark Balloon Protons 2 NEWtron Bunny Gluon e+ neutrinos
::2010/10/23::
Play Video
26
Quark
Quark
::2014/07/24::
Play Video
27
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
::2014/02/05::
Play Video
28
Quarks make proton and neutron History of the UNIVERSE p+ to carbon-12-2
Quarks make proton and neutron History of the UNIVERSE p+ to carbon-12-2
::2009/04/18::
Play Video
29
A down quark
A down quark's effect on the atomic palate.mov
::2010/06/16::
Play Video
30
The Quark song
The Quark song
::2011/06/07::
Play Video
31
PhysicsBootcampAddendumQ29(Particle Physics: Quark Makeup of Baryons).avi
PhysicsBootcampAddendumQ29(Particle Physics: Quark Makeup of Baryons).avi
::2012/01/12::
Play Video
32
Quark-star Definition
Quark-star Definition
::2014/07/12::
Play Video
33
Quark und Co   Leben mit dem Down Syndrom GERMAN DOKU
Quark und Co Leben mit dem Down Syndrom GERMAN DOKU
::2013/11/21::
Play Video
34
Particle accelerators: GCSE revision
Particle accelerators: GCSE revision
::2014/02/12::
Play Video
35
Partículas Fundamentais: O Quark Up
Partículas Fundamentais: O Quark Up
::2013/07/16::
Play Video
36
Electrons, Protons And Neutrons | Standard Model Of Particle Physics
Electrons, Protons And Neutrons | Standard Model Of Particle Physics
::2009/11/19::
Play Video
37
Particle Physics Quark Properties
Particle Physics Quark Properties
::2013/05/03::
Play Video
38
3D mapping brings down the curtains on QUARK
3D mapping brings down the curtains on QUARK'12.mp4
::2012/02/05::
Play Video
39
The Quark Bomb - The Day Bitcoin Died (Quarkcoin Cryptocurrency)
The Quark Bomb - The Day Bitcoin Died (Quarkcoin Cryptocurrency)
::2014/03/26::
Play Video
40
QUARK DOWN - Time (cover Pink Floyd)
QUARK DOWN - Time (cover Pink Floyd)
::2012/09/04::
Play Video
41
The Quark  Song
The Quark Song
::2009/06/20::
Play Video
42
DrumCam - Claire (Quark Down)
DrumCam - Claire (Quark Down)
::2012/04/21::
Play Video
43
Quark Down (Studio TEASER)
Quark Down (Studio TEASER)
::2012/03/11::
Play Video
44
[Hardcore]Quark - It
[Hardcore]Quark - It's going down[Gabba]
::2013/10/08::
Play Video
45
FourSevens Quark Tactical QT2L-X
FourSevens Quark Tactical QT2L-X
::2013/10/09::
Play Video
46
Dextems - Quark [Tamrecords]
Dextems - Quark [Tamrecords]
::2013/05/09::
Play Video
47
d O wN qu ARk gammaray burstday (pRoMO MUSIC VIDEO)
d O wN qu ARk gammaray burstday (pRoMO MUSIC VIDEO)
::2013/07/03::
Play Video
48
dOwnQuArK down´t do it (Laser Love) zAjaC (guitar) vs. kRögER (alto-sax)
dOwnQuArK down´t do it (Laser Love) zAjaC (guitar) vs. kRögER (alto-sax)
::2014/03/25::
Play Video
49
Fundamental Particles
Fundamental Particles
::2014/04/30::
Play Video
50
Quark model with Fractional electric charge is quite wrong.
Quark model with Fractional electric charge is quite wrong.
::2014/03/11::
NEXT >>
RESULTS [51 .. 101]
From Wikipedia, the free encyclopedia
  (Redirected from Down antiquark)
Jump to: navigation, search
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 13 e
Color charge yes
Spin 12
Weak isospin LH: −12, RH: 0
Weak hypercharge LH: 13, RH: −23

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 −13 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-12, 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 5.3 MeV/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 et al. (Particle Data Group) (2013). "PDGLive Particle Summary 'Quarks (u, d, s, c, b, t, b', t', Free)'". 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 et al.; 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 et al.; Friedman, J.; Kendall, H.; Bloom, E.; Coward, D.; Destaebler, H.; Drees, J.; Mo, L.; Taylor, R. (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 et al.; Lai, H.; Olness, Fredrick; Tung, W. (2004). "CTEQ6 Parton Distributions with Heavy Quark Mass Effects". Physical Review D 69 (11): 114005. arXiv:hep-ph/0307022. Bibcode:2004PhRvD..69k4005K. 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]

Wikipedia content is licensed under the GFDL License
Powered by YouTube
LEGAL
  • Mashpedia © 2014