  A measurement of direct photon production in 208Pb + 208Pb collisions at 158
A GeV has been carried out in the CERN WA98 experiment. The invariant yield or
upper limit of direct photons as a function of transverse momentum in the
interval 0.5 < p_T < 4 GeV/c is presented. A significant direct photon excess
is observed at p_T > 1.5 GeV/c in central collisions. The results are compared
to proton-induced results and to theoretical predictions. Implications for the
dynamics of high-energy heavy-ion collisions are discussed.

Nuclear Experiment