Limits on the Production of Direct Photons in 200AGeVS32+AuCollisions

A search for the production of direct photons in $\mathrm{S}+\mathrm{Au}$ collisions at $200A\mathrm{GeV}$ has been carried out in the CERN-WA80 experiment. For central collisions the measured photon excess at each $p_T$, averaged over the range $0.5\le p_T\le 2.5\mathrm{GeV}/c$, corresponded to 5.0% of the total inclusive photon yield with a statistical error of ${\sigma }_{\mathrm{stat}}=0.8\mathrm{}\%$ and a systematic error of ${\sigma }_{\mathrm{syst}}=5.8\mathrm{}\%$. Upper limits on the invariant yield for direct photon production at the 90% C.L. are presented. Possible implications for the dynamics of high-energy heavy-ion collisions are discussed.