Search for relativistic magnetic monopoles with the Baikal neutrino telescope

We present results of a search for relativistic magnetic monopoles with the Baikal neutrino telescope NT200, using data taken between April 1998 and February 2003. No monopole candidates have been found. We set an upper limit 4.6 × 10−17 cm−2 s−1 sr−1 for the flux of monopoles with βm = 1. This is a factor of 20 below the Chudakov–Parker bound which is inferred from the very existence of large-scale galactic magnetic fields.