Experimental Test of Baryon Conservation: A New Limit on Neutron-Antineutron Oscillations in Oxygen

Abstract

This paper reports the result of a search for baryon-number-nonconserving neutron-antineutron transitions in oxygen using a 300-ton water Cherenkov detector located in the Homestake gold mine at a depth of 4200 meters of water equivalent. The 90%-confidence-level upper limit for the neutron partial lifetime for this process is found to be 1.4\ifmmode\times\else\texttimes\fi{}${10}^{30}$ yr. According to a recent calculation of neutron-antineutron oscillations in oxygen, this result corresponds to a lower limit on the free-neutron oscillation time of 2\ifmmode\times\else\texttimes\fi{}${10}^{7}$ sec.