Nuclear modification factor for charged pions and protons at forward rapidity in central Au + Au collisions at 200 GeV

Abstract We present spectra of charged pions and protons in 0–10% central Au + Au collisions at s N N = 200 GeV at mid-rapidity ( y = 0 ) and forward pseudorapidity ( η = 2.2 ) measured with the BRAHMS experiment at RHIC. The spectra are compared to spectra from p + p collisions at the same energy scaled by the number of binary collisions. The resulting nuclear modification factors for central Au + Au collisions at both y = 0 and η = 2.2 exhibit suppression for charged pions but not for (anti-) protons at intermediate p T . The p ¯ / π − ratios have been measured up to p T ∼ 3 GeV / c at the two rapidities and the results indicate that a significant fraction of the charged hadrons produced at intermediate p T range are (anti-) protons at both mid-rapidity and η = 2.2 .