A lunar orbital experiment to detect exospheric neutrons and antineutrons as a probe of baryon number violation.

We propose a small satellite experiment to orbit the moon to probe for $nar{n}$ oscillations predicted by several beyond the standard model theories and important to an understanding of baryogenesis. The best terrestrial $nar{n}$ oscillation experiments that use free neutrons rely on long path lengths inside of large, magnetically sheilded vacuum chambers built near reactor neutron sources. As the quality factor is $propto Nt^2$ for $N$ neutrons and flight time $t$, the hundreds of meters scale required of these chambers has limited the probing power of these efforts. Exospheric neutrons generated by cosmic spallation on the lunar surface are produced with a sufficiently large flux, travel in a low magnetic field, and have long flight path lengths to make an orbital experiment significantly competitive with future proposed terrestrial experiments.