Realistic calculations of nuclear disappearance lifetimes induced by nn̄ oscillations

Realistic calculations of nuclear disappearance lifetimes induced by nn̄ oscillations are reported for oxygen and iron, using n̄ nuclear potentials derived from a recent comprehensive analysis of p̄ atomic X-ray and radiochemical data. A lower limit τnn̄>3.3×108s on the nn̄ oscillation time is derived from the Super-Kamiokande I new lower limit Td(O)>1.77×1032yr on the neutron lifetime in oxygen. Antineutron scattering lengths in carbon and nickel, needed in trap experiments using ultracold neutrons, are calculated from updated N̄ optical potentials at threshold, with results shown to be largely model independent.