Limits on the Flux of Slowly Moving Very Massive Particles Carrying Electric or Magnetic Charge

Abstract

If electrically or magnetically charged particles of the Planck mass or the grand unification mass exist, a measurable flux of them could be reaching Earth but would probably have remained undetected. However, they should make a signature in a properly instrumented detector array. With a small proportional counter array, upper limits between 0.03 and 0.06 ${\mathrm{m}}^{-2\mathrm{}}$ ${\mathrm{sr}}^{-1\mathrm{}}$ ${\mathrm{d}}^{-1\mathrm{}}$ are set on their flux at velocities between 100 and 350 km/sec.