Search for intermediate mass magnetic monopoles and nuclearites with the SLIM experiment

Abstract SLIM is a large area experiment (440 m 2 ) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m 2 at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (10 7 –10 13  GeV/ c 2 ) and nuclearites in the cosmic radiation using stacks of CR-39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10 - 15  cm - 2  s - 1  sr - 1 . We present the results of the calibration of CR-39 and Makrofol and the analysis of a first sample of the exposed detector.