A symmetry, applicable to the $\overline{p}n$ system, called "beam-target reversal symmetry," is derived from the conservation of $G$ parity and is tested using data from an in-flight $\overline{p}d$ bubble-chamber exposure. Beam-target reversal symmetry predicts that for $\overline{p}n$ interactions, both inclusive and exclusive, all reaction products which are eigenstates of $G$ parity have forward-backward-symmetric angular distributions in the center-of-mass frame. The prediction is consistent with experimental event distributions presented.

• Received 18 March 1977

DOI:https://doi.org/10.1103/PhysRevD.16.2679