3 v 1 3 1 O ct 2 00 1 A combined analysis technique for the search for fast magnetic monopoles with the MACRO detector The MACRO Collaboration

We describe a search method for fast moving (β > 5×10) 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 cmssr in the velocity range 5 × 10 ≤ β ≤ 0.99 and for nucleon decay catalysis cross section smaller than ∼ 1mb.