Suppressed π0 Production at Large Transverse Momentum in Central Au + Au Collisions at √sNN = 200 GeV

Transverse momentum spectra of neutral pions in the range I < p T < 10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in Au + Au collisions at s N N = 200 GeV. The π 0 multiplicity in centralreactions is significantly below the yields measured at the same s N N in peripheral Au + Au and p + p reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is ∼2.5 at p T = 2 GeV/c and increases to ∼4-5 at p T 4 GeV/c. At larger p T , the suppression remains constant within errors. The deficit is already apparent in semiperipheral reactions and increases smoothly with centrality.