Search for the Dirac monopole by means of vavilov-cherenkov radiation at the 70 Gev IHEP (Institute for High Energy Physics Serpukhov) proton synchrotron

At the proton energy of 70 GeV on the internal target of the IHEP proton synchrotron the search was made for magnetic charges over the Vavilov-Cherenkov radiation and characteristic polarization. Eight Cherenkov counters of a special construction served as detectors. Possible events were recorded with two fast five-ray oscillographs triggered by 6-fold coincidences. The efficiency of the magnetic charge recording was about 10%.The proton beam of 6.4×10¹⁴ intensity traversed the target-radiator; and not a single case of the production of the Dirac monopole with the magnetic charge from minimal one of about 2/3g_D (g_D=68.5e) up to2g_D was recorded. This means that in the conditions of our experiment the upper boundary of the cross section of the Dirac monopole production by 70 GeV protons per nucleon of Si and O nuclei for magnetic charges of masses from 3 up to 5·5m_p was found to be(95%) 10^–40 cm².On leave fromDepartment of Nuclear Physics, Comenius University, Bratislava, Czechoslovakia.The authors express their gratitude to the workers of the enterprise Dioptra (Turnov, SSR) for making of optical details for the device for SDM.