We have studied the Dalitz plot for the recently observed charged state decaying into $K^{\mp }{\pi }^{\pm }{\pi }^{\pm }$ at 1876 MeV/${\mathit{c}}^2$ and we find that the final state is incompatible with a natural spin and parity assignment. This information, coupled with the earlier observation of the $K^{\pm }{\pi }^{\mp }$ decay mode (a final state of natural spin and parity) of the neutral state at 1865 MeV/${\mathit{c}}^2$, suggest parity nonconservation in the decays of these objects if they are members of the same isomultiplet as their proximity in mass suggests.

• Received 18 October 1976

DOI:https://doi.org/10.1103/PhysRevLett.37.1531