Centrality-dependent modification of jet-production rates in deuteron-gold collisions at $\sqrt{s_{NN}}$=200 GeV

TL;DR

This study measures jet production in proton-proton and deuteron-gold collisions at 200 GeV, revealing that while overall jet rates match expectations, centrality-dependent modifications challenge existing models of nuclear effects.

Contribution

It provides the first detailed measurement of jet production rates in d+Au collisions at RHIC, highlighting centrality-dependent modifications not explained by current models.

Findings

Nuclear modification factor $R_{dAu}$ is consistent with unity overall.

Centrality-dependent $R_{dAu}$ and $R_{CP}$ show significant deviations from unity.

Results challenge conventional models linking hard-process rates and soft-particle production.

Abstract

Jet production rates are measured in $p$$+$$p$ and $d$$+$Au collisions at $\sqrt{s_{NN}}$=200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the $R=0.3$ anti-$k_{t}$ algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multi-wire proportional chambers, and the jet transverse momentum ($p_T$) spectra are corrected for the detector response. Spectra are reported for jets with $12<p_T<50$ GeV/$c$, within a pseudorapidity acceptance of $\left|\eta\right|<0.3$. The nuclear-modification factor ($R_{d{\rm Au}}$) values for 0\%--100\% $d$$+$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.