Our understanding of the ultimate structure of matter has advanced greatly in the last few years. It was nearly twenty years ago that Murray Gell‐Mann and George Zweig gave us the key to much of this understanding with their revolutionary proposals that protons, neutrons and all other strongly interacting particles—the hadrons—are made of quarks, a theretofore unobserved kind of particle. Over the last ten years, this proposal has become firmly established even though we have not observed free quarks directly. More recent research has found that forces between quarks are extremely simple and universal—the same for all types of quarks—and that these forces explain why free quarks cannot be seen. In this article we will look at hadron spectroscopy, which has been one of the main venues for this great progress.

1.
M.
Gell‐Mann
,
Phys. Lett.
8
,
214
(
1964
);
G. Zweig, CERN preprint TH412 (1964) unpublished.
2.
H.
Fritzsch
,
M.
Gell‐Mann
,
H.
Leutwyler
,
Phys. Lett.
47B
,
365
(
1973
);
Y. Nambu in Preludes in Theoretical Physics A. de Sahlit, H. Feshbach, L. van Hove, eds., North‐Holland, Amsterdam (1966) page 133.
3.
For a review of positronium physics see
A.
Rich
,
Rev. Mod. Phys.
53
,
127
(
1981
).
4.
T.
Appelquist
,
H. D.
Politzer
,
Phys. Rev. Lett.
34
,
43
(
1975
);
see also
E.
Eichten
,
K.
Gottfried
,
T.
Kinoshita
,
J.
Kogut
,
K. D.
Lane
,
T.‐M.
Yan
,
Phys. Rev. Lett.
34
,
369
(
1975
).
5.
For reviews of heavy quarkoniums see
T.
Appelquist
,
R. M.
Barnett
,
K.
Lane
,
Ann. Revs. Nucl. Sci.
28
,
387
(
1978
);
C.
Quigg
,
J. L.
Rosner
,
Phys. Rep.
56C
,
167
(
1979
).
6.
J. J.
Aubert
,
U.
Becker
,
J. P.
Biggs
,
J.
Burger
,
M.
Chen
,
G.
Everhart
,
P.
Goldhagen
,
J.
Leong
,
T.
McCorriston
,
T. G.
Rhoades
,
M.
Rohde
,
S. C. C.
Ting
,
S. L.
Wu
,
Y. Y.
Lee
,
Phys. Rev. Lett.
33
,
1404
(
1974
).
7.
J. J.
Augustin
,
A. M.
Boyarski
,
M.
Breidenbach
,
F.
Bulos
,
J. T.
Dakin
,
G. J.
Feldman
,
G. E.
Fischer
,
D.
Fryberger
,
G.
Hanson
,
B.
Jean‐Marie
,
R. R.
Larson
,
V.
Lüth
,
H. L.
Lynch
,
D.
Lyon
,
C. C.
Morehouse
,
J. M.
Paterson
,
M. L.
Perl
,
B.
Richter
,
P.
Rapidis
,
R. F.
Schwitters
,
W. M.
Tanenbaum
,
F.
Vannucci
,
G. S.
Abrams
,3
D.
Briggs
,
W.
Chinowsky
,
C. E.
Friedberg
,
G.
Goldhaber
,
R. J.
Hollebeek
,
J. A.
Kadyk
,
B.
Lulu
,
F.
Pierre
,
G. H.
Trilling
,
J. S.
Whitaker
,
J.
Wiss
,
J. E.
Zipse
,
Phys. Rev. Lett.
33
,
1406
(
1974
).
8.
S. W.
Herb
,
D. C.
Horn
,
L. M.
Lederman
,
J. C.
Sens
,
H. D.
Snyder
,
J. K.
Yoh
,
J. A.
Appel
,
B. C.
Brown
,
C. N.
Brown
,
W. R.
Innew
,
K.
Ueno
,
T.
Yamanouchi
,
A. S.
Ito
,
H.
Jöstlein
,
D. M.
Kaplan
,
R. D.
Kephart
,
Phys. Rev. Lett.
39
,
252
(
1977
).
9.
For reviews of charmonium spectroscopy see, for example,
R. F.
Schwitters
,
K.
Strauch
,
Ann. Rev. Nucl. Sci.
26
,
89
(
1976
);
W.
Chinowsky
,
Ann. Rev. Nucl. Sci.
27
,
393
(
1977
).
10.
For reviews of upsilon spectrscopy, see for example, Karl Berkelman, CLNS preprint 83/564 to be published in Physics Reports;
P.
Franzini
,
J.
Lee‐Franzini
,
Ann. Rev. Nucl. Part. Sci.
33
,
1
(
1983
).
11.
A.
de Rújula
,
H.
Georgi
,
S. L.
Glashow
,
Phys. Rev.
D12
,
147
(
1975
).
12.
For a review of the light hadrons, see L. Montanet in High Energy Physics–1980, L. Durand, L. G. Pondrom, eds., AIP Conf. Proc. 68, Am. Inst. Phys., New York (1981), page 1196.
13.
For a review see
P. J.
O'Donnell
,
Rev. Mod. Phys.
53
,
273
(
1981
).
14.
For reviews of light‐baryon spectroscopy see, for example, N. Isgur in Particles and Fields–1981: Testing the Standard Model, AIP Conf. Proc. 81, C. A. Heusch, W. T. Kirk, eds., Am. Inst. Phys., New York (1982), page 7;
G. Karl in Proceedings of the 19th International Conference on High Energy Physics, S. Homma, M. Kawaguchi, H. Miyazawa, eds., Phys. Soc. Japan, Tokyo (1978), page 135.
15.
For a review see E. D. Bloom, J. de Phys., Colloque C3, supplement no. 12, tome 43, page C3‐407 (1982).
16.
For a review see V. Zacharov in High Energy Physics–1980, L. Durand, L. G. Pondrom, eds., AIP Conf. Proc. 68, Am. Inst. Phys., New York, page 1234.
17.
K. G.
Wilson
,
Phys. Rev.
D10
,
2445
(
1974
).
18.
For reviews of bag models see, for example,
K.
Johnson
,
Acta Physica Polonica
B6
,
865
(
1975
);
P.
Hasenfratz
,
J.
Kuti
,
Phys. Rep.
40
,
75
(
1978
);
for a precursor of this model see
P. N.
Bogolubov
,
Am. Inst. H. Poincaré
8
,
163
(
1967
).
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