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Why Believe in QCD?

  • C. H. Llewellyn Smith
Part of the NATO Advanced Science Institutes Series book series (NSSB, volume 104)

Abstract

I will divide the evidence for QCD into a priori evidence and a posteriori evidence, obtained by comparing specific QCD predictions with data.1 The former consists of the very strong evidence, reviewed below, that hadrons are made of colored quarks which interact through the exchange of vector (spin one) gluons. Evidently the force must be color dependent, since we only see a single π meson rather than the nine different color combinations which can be made from a tricolored quark and antiquark. The only sensible (renormal-izable, unitary etc.) theory of vector gluons coupled to color is QCD [or a color gauge theory based on SO(3) but this turns out to fail the a posteriori tests and will not be discussed further].

Keywords

Total Cross Section Chiral Symmetry Deep Inelastic Scattering Renormalization Group Equation Chiral Limit 
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References

  1. 1.
    Since these lectures are of an introductory nature many of the references are to reviews, where further references may be found, rather than to the original literature. For reviews of QCD see e.g. W. Marciano and H. Pagels, Phys. Rep. 36:137 (1978);ADSCrossRefGoogle Scholar
  2. 1a.
    G. Altarelli, Phys. Rep. 81:1 (1982);ADSCrossRefGoogle Scholar
  3. 1b.
    C.H. Llewellyn Smith, Phil. Trans. Roy. Soc. 304:5 (1982);CrossRefGoogle Scholar
  4. 1c.
    H. D. Politzer, to be published in Proc. XXI International Conference on High Energy Physics, Paris 1982.Google Scholar
  5. 2.
    R. Feist, in: “Proc. 1981 Symposium on Lepton and Photon Interactions at High Energy,” W. Pfeil, ed., University of Bonn, Bonn (1981).Google Scholar
  6. 3.
    S. L. Adler, in: “Lectures on Elementary Particles and Quantum Field Theory,” S. Deser, M. Grisaru and H. Pendelton, eds., MIT Press, Cambridge (1970);Google Scholar
  7. 3.
    R. Jackiw, in: “Lectures on Current Algebra and its Applications,” by S. Teiman, R. Jackiw and D. Gross, Princeton University Press, Princeton (1972).Google Scholar
  8. 4.
    V. De Alfaro et al., “Currents in Hadron Physics”, North-Holland, Amsterdam (1973);Google Scholar
  9. 4a.
    H. Pagels, Phys. Rep. 5:219 (1975).MathSciNetADSCrossRefGoogle Scholar
  10. 5.
    D. J. Gross and F. Wilczek, Phys. Rev. Lett. 30:1343 (1973);ADSCrossRefGoogle Scholar
  11. 5a.
    H. D. Politzer, Phys. Rev. Lett. 30:1346 (1973).ADSCrossRefGoogle Scholar
  12. 6.
    R. P. Feynman, in: “Weak and Electromagnetic Interactions at High Energy,” R. Balian and C. H. Llewellyn Smith, eds., North Holland, Amsterdam (1977).Google Scholar
  13. 7.
    A. De Rujula, H. Georgi and S. L. Glashow, Phys. Rev. D12:147(1975);ADSGoogle Scholar
  14. 7.
    N. Isgur, in: “Proc. Madison Conference on High Energy Physics,” L. Durand and L. G. Pondrom, eds., Madison (1980).Google Scholar
  15. 8.
    C. Rebbi, to be published in “Proc. XXI International Conference on High Energy Physics,” Paris 1982, and references therein.Google Scholar
  16. 9.
    The discussion in this section is simplified e.g. I have ignored external line corrections and subtleties such as gauge dependence. For a proper discussion see any modern book on quantum field theory, for example, C. Itzykson and J.-B. Zuber, “Quantum Field Theory,” McGraw Hill, New York (1980).Google Scholar
  17. 10.
    See Refs. 1 and A. H. Mueller, Phys. Rep. 73:237 (1981);ADSCrossRefGoogle Scholar
  18. 10.
    Yu. L. Dokshitser et al., Phys. Rep. 58:269 (1980)ADSCrossRefGoogle Scholar
  19. 10.
    E. Reya, Phys. Rep. 69:195 (1981).ADSCrossRefGoogle Scholar
  20. 10a.
    For a more detailed discussion from a similar point of view to that followed in these lectures see C. H. Llewellyn Smith, to be published in Proc. 1981 NATO Banff Summer Institute.Google Scholar
  21. 11.
    T. Kinoshita, J. Math. Phys. 3:650 (1962);ADSMATHCrossRefGoogle Scholar
  22. 11a.
    T. D. Lee and M. Nauenberg, Phys. Rev. 133:B1349 (1964).MathSciNetCrossRefGoogle Scholar
  23. 12.
    G. T. Bodwin, S. Brodsky and G. P. Lepage, Phys. Rev. Lett. 47:1799 (1981) and S. Brodsky, this volume, have discovered effects which may spoil the stronger assumption, which has often been made, that the function which absorbs the m dependence is “universal” i.e. totally process independent.ADSCrossRefGoogle Scholar
  24. 13.
    For a general review of jet production in e+e- annihilation, both on and off resonances, see K. H. Mess and B. H. Wiik, DESY preprint 82–011 (1982).Google Scholar
  25. 14.
    Ch. Berger et al., Phys. Lett. 78B:176 (1978) and 82B:449 (1979).ADSGoogle Scholar
  26. 15.
    J. Bienlein, in: “Proc. 1981 Symposium on Lepton and Photon Interactions at High Energy”, W. Pfeil, ed., University of Bonn, Bonn (1981);Google Scholar
  27. 15a.
    B. Niczyporuk et. al., Zeit. Phys. C9:1 (1981).ADSGoogle Scholar
  28. 16.
    R. P. Feynman, “Photon-Hadron Interactions”, Benjamin, Reading (1972);Google Scholar
  29. 16a.
    F. E. Close, “An Introduction to Quarks and Partons”, Academic Press, London (1978);Google Scholar
  30. 1b6.
    C. H. Llewellyn Smith, in: “Hadron Structure and Lepton-Hadron Interactions”, M. Levy et al., eds., Plenum, New York (1979).Google Scholar
  31. 17.
    J. Kogut and L. Suskind, Phys. Rev. D9:697 and 3391 (1974).ADSGoogle Scholar
  32. 18.
    P. Bosetti et al., Nucl. Phys. B140:1 (1980);Google Scholar
  33. 18a.
    H. Anderson et al., Phys. Rev. Lett. 40:1061 (1978);ADSCrossRefGoogle Scholar
  34. 18b.
    J. G. H. de Groot et al., Zeit. Phys. Cl:143 (1979).Google Scholar
  35. 19.
    H. Wahl, loc. cit. Google Scholar
  36. 20.
    F. Eisele, to be published in “Proc. XXI International Conference on High Energy Physics,” Paris 1982.Google Scholar

Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • C. H. Llewellyn Smith
    • 1
  1. 1.Department of Theoretical PhysicsOxfordEngland

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