New limit on the flux of slowly moving magnetic monopoles

Abstract

A search for slowly moving superheavy magnetic monopoles has been performed using a combination of scintillation counters and proportional chambers which are situated on the ground near sea level. The minimum threshold threshold of the energy loss is set at 1/20 of the minimum ionisation. An upper flux limit of 1.8*10-12 cm-2 sr-1 s-1 for magnetic monopoles was obtained over a wide velocity range from 2.5*10-4 c to 1.0*10-1 c at the 90% confidence level. The velocity range for the trigger system was set from 10-4 c to 10-1 c.