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To Catch a Monopole

1982; Society for Science and the Public; Volume: 122; Issue: 23 Linguagem: Inglês

10.2307/3967147

1943-0930

Dietrick E. Thomsen,

Experimental and Theoretical Physics Studies

Second of two articles Physics often seems to progress by a kind of dialectic. Physicists have a liking for symmetry. Given a situation that lacks symmetry, they look for means of providing it, but often the logic of the search drives them to an overbalance, and they are left in a new and different asymmetrical situation. Magnetic monopoles are such a case. They were first intended to complete the symmetry between electricity and magnetism. Electricity and magnetism are reciprocal and symmetrical phenomena except that there didn't seem to be any magnetic correspondents to simple electric charges of one sign or the other, such as electrons and positrons. The smallest magnets always came with north and south poles inseparably bound together. The search for a theoretical description of a possible magnetic monopole at first focused on a magnetic equivalent to the electron, a simple, point magnetic charge. However, the intervention of the new grand unified theories (GUTs), which are the latest attempts to unify all of physics in a single explanation, drove the situation way beyond balance. GUTs yield grand unified monopoles (GUMs), which are monster particles of a sort never before contemplated (SN: 11/27/82, p. 248). Electrons with a mass of 511,000 electron-volts are the lightest things in physics except for two or three particles that have no rest mass at all. GUMs are by far the heaviest things ever called subatomic particles. Theorists think their mass should lie between 1016 and 10'9 billion electron-volts. Electrons are supposed to be geometrical points or nearly so, simple unstructured things whose main function is to emanate electric forces. Originally theorists expected that monopoles would be the same, except for emanating magnetic forces in place of electric. GUMs, however, have a rich and complex structure that links them to a wide variety of phenomena beyond electromagnetism. Even more important, the nature of GUTs brings GUMs to center stage. GUMs are one of two ways that physicists with their present capabilities can hope to find experimental evidence confirming GUTs. GUTs are extremely important. Generations of physicists have striven for such a unification of the science. With a very large part of it seemingly done in theory, experimenters are going to lose no opportunity to try to nail it down observationally. The question of the hour is where to look for GUMs and how to try to find them. As the recent Magnetic Monopole Workshop, held at Racine, Wis., indicated, experimentalists faced with such an unprecedented quarry are groping more than a little. There are many disagreements and contradictory suggestions. A variety of To Catch a Monopole