Jet production rates are measured in $p$$+$$p$ and $d$$+$Au collisions at $sqrt{s_{NN}}$=200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the $R=0.3$ anti-$k_{t}$ algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multi-wire proportional chambers, and the jet transverse momentum ($p_T$) spectra are corrected for the detector response. Spectra are reported for jets with $12<p_T<50$ GeV/$c$, within a pseudorapidity acceptance of $left|etaright|<0.3$. The nuclear-modification factor ($R_{d{rm Au}}$) values for 0%--100% $d$$+$Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. However, the centrality-selected $R_{d{rm Au}}$ values and central-to-peripheral ratios ($R_{rm CP}$) show large, $p_T$-dependent deviations from unity, which challenge the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei.
Download