High PT π0 production and angular correlations in 158 AGeV p+A and Pb+Pb collisions Original Research Article

Recent results of the WA98 experiment with p and Pb induced reactions at 158 AGeV are presented. Azimuthal γ-γ correlations at high PT were studied in search for a signal of jet-like structures. A clear indication for back-to-back correlations can be seen in p+A with a strong dependence on the PT of the photons and the size of the system. In Pb+Pb collisions in plane elliptic flow has been observed. Results on transverse mass spectra of neutral pions measured at central rapidity are presented for impact parameter selected Pb+Pb collisions. In going from peripheral to medium central collisions there is a nuclear enhancement increasing with transverse mass similar to the Cronin effect, while for very central collisions this enhancement appears to be weaker than expected.