Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at √sNN = 200 GeV

Abstract

Jet production rates are measured in p þ p and d þ Au collisions at √sNN = 200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R ¼ 0.3 anti-kt algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (pT ) spectra are corrected for the detector response. Spectra are reported for jets with 12 < pT < 50 GeV=c, within a pseudorapidity acceptance of jηj < 0.3. The nuclear-modification factor (RdAu) values for 0%–100% d þ Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. However, the centralityselected RdAu values and central-to-peripheral ratios (RCP) show large, pT-dependent deviations from unity, challenging the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei.