2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/81066A 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.56 pages, 33 figures. Submitted to Phys. Rev. CNuclear Experimenttext