We report measurements from experiment E864 at the BNL-AGS of the yields of particle unstable light nuclei in central collisions of ${}^{197}\mathrm{Au}$ with beam momentum of $11.5A$ $\mathrm{GeV}/c$ on ${}^{197}\mathrm{Pt}.$ Yields are reported as a function of rapidity for the nuclei ${}^4\mathrm{H},$ ${}^4\mathrm{Li},$ ${}^5\mathrm{He},$ and ${}^5\mathrm{Li}$ in the rapidity range from $y_{\mathrm{c}.\mathrm{m}.\mathrm{}}$ to $y_{\mathrm{c}.\mathrm{m}.\mathrm{}}+0.8\mathrm{}$ and in the transverse momentum range of approximately $0.1<~p_T/A<~0.4\mathrm{GeV}/c.\mathrm{}$ The yields are compared to previously reported yields and trends for the production of stable light nuclei. The nonobservation of two excited states ${}^5{\mathrm{He}}_{16.75\mathrm{MeV}}^{*}$ and ${}^5{\mathrm{Li}}_{16.66\mathrm{MeV}}^{*}$ is used to set an upper limit on the yields of these states.

• Received 19 October 2000

DOI:https://doi.org/10.1103/PhysRevC.65.014906