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

TL;DR

This paper presents a novel combined detection method using multiple subdetectors in the MACRO experiment to search for fast magnetic monopoles, setting stringent upper flux limits after analyzing over two years of data.

Contribution

It introduces a new combined analysis technique utilizing scintillator, streamer tube, and track-etch detectors for magnetic monopole searches, improving detection reliability.

Findings

No magnetic monopoles detected in the data sample.

Established a 90% CL upper flux limit of 1.5 x 10^{-15} cm^{-2} s^{-1} sr^{-1}.

Set constraints on monopole velocity range and nucleon decay catalysis cross section.

Abstract

We describe a search method for fast moving ($\beta > 5 \times 10^{-3}$) 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 $1.5 \times 10^{-15} cm^{-2} s^{-1} sr^{-1}$ in the velocity range $5 \times 10^{-3} \le \beta \le 0.99$ and for nucleon decay catalysis cross section smaller than $\sim 1 mb$.