Limits on $\text{boldmath}n\bar{n}$ oscillations from nuclear stability

Abstract

The relationship between the lower limit on the nuclear stability lifetime as derived from the non disappearance of `stable` nuclei ($T_d\gtrsim 5.4\times 10^{31}$ yr), and the lower limit thus implied on the oscillation time $({\tau }_{n\bar{n}})$ of a possibly underlying neutron-antineutron oscillation process, is clarified by studying the time evolution of the nuclear decay within a simple model which respects unitarity. The order-of-magnitude result ${\tau }_{n\bar{n}}\approx 2(T_d/{\Gamma }_{\bar{n}}{)}^{1/2}>2\times 10^8$ sec, where ${\Gamma }_{\bar{n}}$ is a typical $\bar{n}$ nuclear annihilation width, agrees as expected with the limit on ${\tau }_{n\bar{n}}$ established by several detailed nuclear physics calculations, but sharply disagreeing by 15 orders of magnitude with a claim published recently in Phys. Rev. CRAP.

Comments: 8 pages; this PRC version (accepted for publication, November 4 1999) differs from the original version only by a few minor editorial changes