The electron dipole moment—A case history

FEB 01, 1966

The anomalous magnetic moment of the electron is of great significance in the study of elementary particles and quantum electrodynamics. The history of its discovery is in large part the story of a technique:—the use of molecular beams—which was not invented for the specific purpose hut which did, by permitting a discrepancy to appear where none was expected, answer an unasked question.

DOI: 10.1063/1.3048048

Polykarp Kusch

THE ELECTRON is one of the fundamental particles in the universe and is likely to remain one. It is as abundant as any other particle with the possible exception of the neutrino. There may be more neutrinos around, but I am not expert on that question. The electron has a definite charge and a definite rest mass.

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References

1. Reprints of both Thomson’s and Millikan’s papers appear in Great Experiments in Physics. Morris Shamos, Ed. Henry Holt, New York, 1959.
2. As is true of almost every major event in the history of physics, the proposals of Goudsmit and Uhlenbeck were not made without some previous provocative suggestions. See, for instance, Whittaker, A History of the Theories of Aether and Electricity, Vol. II, pages 133, 134. Harper, New York, 1960.
3. Kinsler: Phys. Rev. 46, 533 (1934).https://doi.org/PHRVAO
4. Dunoyer: Compt. rend. 152, 592 (1911); https://doi.org/COREAF
J. Phys. Radium, 8, 142 (1911).
5. Stern: Gerlach and Stern: Z. Physik, 7, 249 (1921); https://doi.org/ZEPYAA
Stern: Gerlach and Stern, 8, 110 (1922); https://doi.org/ZEPYAA , Z. Phys.
Stern: Gerlach and Stern, 9, 349 (1922).https://doi.org/ZEPYAA , Z. Phys.
6. The emphasis on the molecular‐beam magnetic‐resonance method as a generalized spectrometric procedure is not made in the early papers. In 1939 Rabi, Millman, Kusch, and Zacharias (Phys. Rev. 55, 526) discussed the trajectories of molecules in a system of inhomogeneous magnetic fields and, very importantly, the process of changing the orientation of a magnetic dipole in a magnetic field.
7. Taylor: Z. Physik, 57, 242 (1929).https://doi.org/ZEPYAA
8. Rabi, Zacharias, Millman, Kusch: Phys. Rev. 53, 318 (1938).https://doi.org/PHRVAO
9. The use of the two‐wire system for producing inhomogeneous magnetic fields with precisely calculable properties was described by Rabi, Kellogg and Zacharias in 1934. The extrapolation of the system to iron magnets in which much higher fields would be produced was described by Millman, Rabi and Zacharias in 1938. (Phys. Rev. 53, 384).
10. Rabi, Zacharias, Millman, Kusch: Phys. Rev. 53, 318 (1938).https://doi.org/PHRVAO
11. Millman: Phys. Rev. 55, 628 (1939).https://doi.org/PHRVAO
12. Kellogg, Rabi, Ramsey: Phys. Rev. 56, 728 (1939).https://doi.org/PHRVAO
13. Kellogg, Rabi, Ramsey, Zacharias: Phys. Rev. 57, 677 (1940).https://doi.org/PHRVAO
14. Kusch, Millman, Rabi: Phys. Rev. 57, 765 (1940).https://doi.org/PHRVAO
15. Zacharias: Phys. Rev. 61, 270 (1942).https://doi.org/PHRVAO
16. Millman, Kusch: Phys. Rev. 60, 91 (1941).https://doi.org/PHRVAO
17. Becker, Kusch: Phys. Rev. 73, 584 (1948).https://doi.org/PHRVAO
18. Hardy, Millman: Phys. Rev. 61, 459 (1942).https://doi.org/PHRVAO
19. Nafe, Nelson, Rabi: Phys. Rev. 71, 914 (1947); https://doi.org/PHRVAO
Nafe, Nelson: Phys. Rev. 75, 1194 (1949).https://doi.org/PHRVAO
20. Breit: Phys. Rev. 72, 984 (1947).https://doi.org/PHRVAO
21. Kusch, Foley: Phys. Rev. 72, 1256 (1947).https://doi.org/PHRVAO
22. Foley, Kusch: Phys. Rev. 73, 412 (1948).https://doi.org/PHRVAO
23. Kusch, Foley: Phys. Rev. 74, 250 (1948).https://doi.org/PHRVAO
24. Schwinger: Phys. Rev. 73, 416 (1948).https://doi.org/PHRVAO
25. Schwinger: Phys. Rev. 73, 416 (1948).https://doi.org/PHRVAO
26. Taub, Kusch: Phys. Rev. 75, 1481 (1949).https://doi.org/PHRVAO
27. Kusch, Taub: Phys. Rev. 75, 1477 (1949).https://doi.org/PHRVAO
28. Gardner, Purcell: Phys. Rev. 76, 1262 (1949); https://doi.org/PHRVAO
Gardner, Purcell, 83, 996 (1951).https://doi.org/PHRVAO , Phys. Rev.
29. Karplus, Kroll: Phys. Rev. 77, 536 (1950).https://doi.org/PHRVAO
30. Koenig, Prodell, Kusch: Phys. Rev. 88, 191 (1952).https://doi.org/PHRVAO
31. Franken, Liebes: Phys. Rev. 104, 1197 (1956); https://doi.org/PHRVAO
Franken, Liebes, 116, 633 (1959).https://doi.org/PHRVAO , Phys. Rev.
32. Sommerfield: Phys. Rev. 107, 328 (1957).https://doi.org/PHRVAO
33. Beringer, Heald: Phys. Rev. 95, 1474 (1954).https://doi.org/PHRVAO
34. Wilkinson, Crane: Phys. Rev. 130, 852 (1963).https://doi.org/PHRVAO

More about the Authors

Polykarp Kusch. Columbia University.