A bound system of ${\mathrm{\pi }}^{\mathrm{-}}$ and neutrons (pineuts) was searched for in the fragmentation region of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ + Be collisions at 100A MeV. The upper limits for the production cross sections were obtained to be 0.08 and 0.20 nb at the 90% confidence level for singly charged systems ${\mathrm{\pi }}^{\mathrm{-}}$${\mathit{n}}^2$ and ${\mathrm{\pi }}^{\mathrm{-}}$${\mathit{n}}^3$, respectively.

• Received 2 November 1992

DOI:https://doi.org/10.1103/PhysRevC.47.2673