On neutron-antineutron oscillation processes in solar cosmic-rays and   the possibility of their observation
  The experimental observation of neutron - antineutron oscillations is one of the oldest problems of elementary-particle physics. However, the search for these processes in the laboratories on the Earth have thus far yielded no results. In this paper, we consider the possibility of finding $n - \tilde n$ oscillations in the solar cosmic rays at flare increases. There are two arguments in favour of such an approach to this problem: a long distance for a neutron run and a weak magnetic field in the solar cosmic-ray environment. Therefore, the presence of antinucleons in solar cosmic rays may be a evidence of the existence of $n - \tilde n$ oscillations. The intensities expected of the $\tilde n$ and $\tilde p$ fluxes near the Earth are found. 
L. S. Molchatsky
hep-ph