First Results from a Superconductive Detector for Moving Magnetic Monopoles

Abstract

A velocity- and mass-independent search for moving magnetic monopoles is being performed by continuously monitoring the current in a 20-${\mathrm{cm}}^{2}$-area superconducting loop. A single candidate event, consistent with one Dirac unit of magnetic charge, has been detected during five runs totaling 151 days. These data set an upper limit of 6.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ ${\mathrm{sr}}^{\ensuremath{-}1}$ for magnetically charged particles moving through the earth's surface.