Monopole searches

Grand Unified Theories of the basic interactions predict the existence of magnetic monopoles whose properties are calculable (74H1, 74P1). The monopole mass is related to the mass of the vector boson which is the carrier of the unified interaction, M/sub M/=m/sub v///sup α//sub GUT/. Also the monopole size is related to the mass of the GUT vector boson, r/sub c/=(m/sub v/)/sup -1/. The monopole magnetic charge should be a multiple of the Dirac charge (31D1). Monopole catalysis of proton decay is very likely to occur, but it is model dependent (85R1). As far as the monopole flux is concerned the predictions vary wildly, from too many to too few monopoles. There are more uncertainties in the predictions of supersymmetric GUT theories, of Kaluza-Klein theories and of Superstrings (86G1). For instance the situation with the catalysis of proton decay in Kaluza-Klein theories is still unclear, and in some models it does not exist. Some Superstring models predict the existence of multiply charge magnetic monopoles. A large number of astrophysical consequences from the existence of monopoles have been studied. Though interesting, most of them seem to have loop-holes and large uncertainties. From the experimental point of view there are now few direct searches in progress, all of medium-large size. Experiments under construction are all very large