A combined analysis technique for the search for fast magnetic monopoles with the MACRO detector

Abstract

We describe a search method for fast moving ( β= v/ c>5×10 −3) magnetic monopoles using simultaneously the scintillator, streamer tube and track-etch subdetectors of the MACRO apparatus. The first two subdetectors are used primarily for the identification of candidates while the track-etch one is used as the final tool for their rejection or confirmation. Using this technique, a first sample of more than two years of data has been analyzed without any evidence of a magnetic monopole. We set a 90% CL upper limit to the local monopole flux of 1.5×10 −15 cm −2 s −1 sr −1 in the velocity range 5×10 −3⩽ β⩽0.99 and for nucleon decay catalysis cross-section smaller than ∼1 mb