Abstract
Lord Kelvin once wrote that every basic principle worth mentioning had already been discovered and that all that was needed were more precise measurements. Shortly after that, in 1897, J.J. Thomason discovered the first lepton (the electron) and opened the first chapter of elementary particle physics. The discovery of the J particle in 1974, interpreted as the bound state of a quark-antiquark pair with a new flavor, charm (much in the same fashion as the hydrogen atom is the bound state of the proton and electron), put the finishing touch to the hypothesis that quarks are the fundamental building blocks of all hadrons. Now we know our universe is likely to be made of 6 leptons and 6 quarks. They interact with each other by means of 4 interactions: nuclear (or strong), electro-magnetic, weak forces and gravity; each is distinctively different in nature and in magnitude at the energy scale commonly available in nature. Each of these forces is characterized by a coupling constant which roughly determines the size of the interaction. Most of our daily phenomena, from the maximum height of a mountain and living beings to temperatures of the sun and the earth can be explained in terms of these constants. Since Einstein’s unsuccessful efforts to unify gravity with electromagnetic forces at low energies, physicists have attempted, over many years, to unify these interactions at much higher energies than presently available in the laboratories. According to these speculations, the coupling constants of all forces will change with energy and at sufficiently high energy they will become comparable in size (Fig. 1). This property of changing with energy resulted in the name of “running coupling constants”. In these lectures we will take a few examples, primary from e+e− annihilation to illustrate the effort in measuring these constants at different energies.
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References
For example, see A. Zichichi et al., Phys. Rev. Lett.6, 128, (1961) and the reference there
K. V. Klitzing et al., Phys. Rev. Lett. 45, 494, (1980);
B. Aedva et al., Phys. Rep. 109, # 3 and 4, 133, (1984);
C.C. Zhang, DESY 85–073, (1985);
S.L. Glashow, Nucl. Phys. 22, 579, (1961);
S. Weinberg, Phys. Rev. Lett. 19, 1264, (1967)
S. Weinberg, Phys. Rev. D5, 1412, (1972);
A. Salam in: Elementary Particle Theory, ed. N. Svartholm, Stockholm, (1968) p. 361;
S.L. Glashow et al., Phys. Rev. D2, 1285, (1970);
R. Budny, Phys. Lett. 55B, 227, (1975);
B. Adeva et al., Phys. Rev. Lett. 48, 1701, (1982,)
B. Adeva et al., Phys. Rep. 109, # 3 and 4, 133, (1984,)
B. Adeva et al., Phys. Rev. Lett. 55, 665, (1985,)
CELLO: H.J. Behrend et al., Zeit.f.Phys.C14,283, (1982,)
JADE: W. Bartel et al., Phys. Lett. 108B, 140, (1982,)
JADE: Zeit. f. Phys. C26, 507, (1985,)
PLUTO: Ch. Berger et al., Zeit. f. Phys. C7, 289, (1981)
PLUTO: Zeit. f. Phys. C21, 53, (1983,)
TASSO: M. Althoff et al., Zeit. f. Phys. C22, 13, (1984)
R. Brandelik et al., Phys. Lett. 1108, 173, (1982)
E. Fernandez et al., Phys. Rev. Lett. 50, 1238, (1983);
T. Himel et al., Phys. Rev. Lett. 41, 449, (1978);
M. E. Levi et al., Phys. Rev. Lett. 51, (1941, (1984);
M. Derrick et al., Argonne National Laboratory Report, -HEP-PR-84–71 and D. Bender et al., Phys. Rev. D30 515, (1984);
F.A. Behrends and R. Kleiss, Nucl. Phys.B177,237, (1981,)
Nucl. Phy-s. B186, 22, (1981, and programs which they have supplied);
G. Passarino and M. Veltman, Nucl. Phys. B160, 151, (1979);
G. Passarino, Nucl. Phys. B204, 237, (1982,)
W. Wetzel, Nucl. Phys. 8227, 1, (1983);
B. W. Lynn and R.G. Stuart, Nucl. Phys. B253, 216, (1985);
F.A. Berends, R. Kleiss, S. Jadach, Nucl. Phys. B202, 63, (1983);
R. Decker, E.A. Paschos and R.W. Brown, Phys. Rev. Lett. 52 1192, (1984);
M. Böhm and W. Hollik, Nucl. Phys. B204, 45, (1982)
M. Böhm and W. Hollik, Phys. Lett. 139B 213, (1984);
G. Arnison et -NT., Phys. Lett. 129B, 273, (1983);
P. Bagnaia et al., Zeit. f. Phys. C24, 1, (1984.)
D.P. Barber et al., Phys. Rev. Lett. 43, 830 , (1979. It was established here that the angular width of each jet is much smaller than the separation between the jets.)
R. Brandelik et al., Phys. Rev. Lett. 86B, 243, (1979).
G. Wolf, DESY Report 83–96, (1983)
T.F. Walsh, Proceedings of the International Europhysics Conference on High Energy Physics, Brighton , U.K., 20–27 July 83, p. 545 and P. Soeding, p. 567.)
M. Chen, MIT-LNS report #137 and Proceeding of the International School of Subnuclear Physics at Erice, Aug. (1983)
In this paper we use the MS scheme for the definition of. W.J. Marciano, Phys. Rev. D29, 580 , (1984.)
R.K. Ellis et al., Nucl. Phys. B168, 409, (1981.)
Z. Kunszt, Phys. Lett. 99B, 429, (1981)
Z. Kunszt, Phys. Lett. 107B, 123, (1981);
A. Ali, Phys. Lett. 110B, 67, (1982)
F.A. Berends and R. Kleiss, Nucl. Phys. B178, 141, (1981.)
F. Fabricus et al., Phys. Lett. 97B, 431, (1981);
F. Gutbrod et al., Zeit. f. Phys. C21, 235, (1984.)
R.Y. Zhu, Ph.D.Thesis, Massachusetts Institute of Technology, (1983, unpublished.)
B. Adeva et al., Phys. Rep. 109, Nos. 3 and 4, 133, (1984.)
C.L. Basham, L. Brown, S. Ellis, and S. Love, Phys. Rev. D19, 2018, (1979.)
F. Csikor et al., Phys. Rev. D31, 1025, (1985.)
A Ali, F. Barreiro, Nucl. Phys. B236, 269, (1984.)
A. Ali et al., Phys. Lett. 93B, 155, (1980)
A. Ali et al., Nucl. Phys. Lett. 78B, 12, (1978);
see also: R.D. Field and R.P. Feynman, Nucl. Phys. B136, 1, (1978.)
Our data is best described by this model with the fragmentation parameter oq=300MeV.)
B. Andersson, G. Gustafson, and T.Sjôstrand, Zeit. f. Phys. C6, 235, (1980);
Nucl. Phys. B197, 45, (1982.)
Likewise, in this model we find oq=420MeV.
Our results are insensitive to the exact values of oq used in either model.
B. Adeva et al., Phys. Rev. Lett. 50, 2051, (1983)
W. Bartel et al., Phys. Lett. 119B, 239, (1982)
W. Bartel et al., Zeit. f. Phys. C25, 231, (1984);
H.J. Behrend et al., Phys. Lett. 138B, 311, (1984);
G. Wolf, DESY 83–96, (1983);
P. Soeding, Proceedings of the International Europhysics Conference on High Energy Physics, Brighton, 83, p. 567;
M. Althoff et al., DESY 84–057, (1984);
E. Fernandez et al., SLAC-PUB-3385, (1984.)
M. Chen, MIT-LNS Report No. 137 and Proceedings of the International School of Subnuclear Physics at Erice Summer School, Aug. (1983);
T.D. Gottschalk and M.P. Schatz, California Institute of Technology Reports: CALT-68–1173 and CALT-68–1199, Phys. Lett. 150B,451, (1985)
B. Adeva et al, Phys. Rev. Lett. 54, 1750, 85.)
These studies conclude that the approximate formulae commonly used , (22) will yield αs values ≈ 25% too high for the Є,δ cut when soft partons are discarded and 5 to 10% too high for M cut. We emphasize that the calculation used here and in the previous work, (23,28) of MARKJ do not involve the mentioned approximations.
Ch. Berger et al.,DESY Report 85–039, (1985.)
P.B. Mackenzie and G.P. Lepage, Phys.Rev.Lett. 47, 1244, (1981);
S. J. Brodsky et al. Phys. Rev. D28,228, (1983);
P. Avery et al., Phys. Rev. Lett. 50, 807, (1983);
C. Klopfenstein et al.,CUSB 83–07;
P. Franzini, private communication.
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© 1988 Plenum Press, New York
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Chen, M. (1988). Measuring the Running Coupling Constant of the Strong, the Electromagnetic and Weak Forces. In: Zichichi, A. (eds) Old and New Forces of Nature. The Subnuclear Series, vol 23. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-1309-0_9
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