Upper Limit on Flux of Cosmic-Ray Monopoles Obtained with a Three-Loop Superconductive Detector

Abstract

A three-loop superconductive monopole detector has been continuously operated for over 150 days. Its sensing area is 476 ${\mathrm{cm}}^{2}$ (71 ${\mathrm{cm}}^{2}$ loop area and 405 ${\mathrm{cm}}^{2}$ near-miss area) for double coincidence events. The data, which contain no candidate events, set an upper limit of 3.7 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ ${\mathrm{sr}}^{\ensuremath{-}1}$ (90% C.L.) for monopoles of any mass and at any velocity passing through the Earth's surface.