A New Evaluation Of The N Anti-n Oscillation Time.

The neutron-antineutron oscillation time τ is evaluated through the study of ΔB=2 transitions in nuclei. A description of the neutron-nucleon and of the antineutron-nucleon interaction in terms of explicit meson exchange is employed, but for the shortest distances which are dealt with phenomenologically. Utilizing the most recent bound on the nucleon lifetime, a lower limit τ⪆3×107 s is found