Studies of Nucleon-Gold Collisions at 200 GeV per Nucleon Pair Using Tagged d+Au Interactions

Abstract

The spectra of charged hadrons produced near mid-rapidity in d+Au, p+Au and n+Au collisions at 200 GeV center of mass energy per nucleon pair are presented as a function of transverse momentum and centrality. These measurements were performed using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). Nucleon-nucleus interactions were extracted from the d+Au data by identifying the deuteron spectators. The deuteron spectators were measured using two calorimeters; one that detected forward-going single neutrons and a newly installed calorimeter that detected forward-going single protons. The large suppression of high-pT hadron production in central Au+Au interactions relative to a naive superposition of p+pbar collisions has been interpreted as evidence of partonic energy loss in a dense medium. This interpretation is founded upon the absence of such suppression in the yield of d+Au collisions. It is shown that d+Au is indeed a valid reference system, as hadron production in d+Au agrees with a simple binary collision scaling of hadron production in p+Au. An ideal reference for Au+Au collisions is constructed using a weighted combination of p+Au and n+Au yields and is found to be similar to the d+Au reference. Further, hadron production in p+Au interactions is compared to that of n+Au interactions, in order to study the transport of charge from the initial state to mid-rapidity. No asymmetry between the positively and negatively charged hadron spectra of p+Au and n+Au interactions is observed for particles having an average pseudo-rapidity of 0.8. A study of the Cronin enhancement of hadrons produced in d+Au collisions using different centrality measures is also presented. A smooth evolution with centrality is observed, independent of the chosen centrality measure, when centrality is parameterized by the multiplicity density measured near mid-rapidity.

arXiv commentSee also http://hdl.handle.net/1721.1/39484

References in corpus (50)

• Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
• Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
• Quark Gluon Plasma an Color Glass Condensate at RHIC? The perspective from the BRAHMS experiment
• The PHOBOS Perspective on Discoveries at RHIC
• Background Independent Quantum Gravity: A Status Report
• Radiative energy loss and $p_{\perp }$-broadening of high energy partons in nuclei
• Suppression of Hadrons with Large Transverse Momentum in Central Au+Au Collisions at $sqrt {s sub {sub {NN}}}_ = 130 GeV
• HIJING 1.0: A Monte Carlo Program for Parton and Particle Production in High Energy Hadronic and Nuclear Collisions
• Hadron production in central nucleus-nucleus collisions at chemical freeze-out
• Transverse momentum and collision energy dependence of high $p_T$ hadron suppression in Au+Au collisions at ultrarelativistic energies
• Evidence from d+Au measurements for final-state suppression of high $p_T$ hadrons in Au+Au collisions at RHIC
• Centrality dependence of high pT hadron suppression in Au+Au collisions at sqrt(sNN)=130 GeV
• Formation of superdense hadronic matter in high energy heavy-ion collisions
• Saturation Physics and Deuteron--Gold Collisions at RHIC
• Evolution of the nuclear modification factors with rapidity and centrality in d+Au collisions at $\sqrt{s_{NN}} = 200 GeV
• Cronin Effect and High-p_T Suppression in pA Collisions
• Observable implications of geometrical and dynamical aspects of freeze-out in heavy ion collisions
• Thermal hadron production in pp and p{\bar p} collisions
• A Multi-Phase Transport model for nuclear collisions at RHIC
• Parton saturation and N_part scaling of semi--hard processes in QCD
• Cross Sections and Transverse Single-Spin Asymmetries in Forward Neutral-Pion Production from Proton Collisions at \sqrt{s} = 200 GeV
• Centrality Dependence of Direct Photon Production in sqrt(s_NN) = 200 GeV Au+Au Collisions
• Centrality dependence of charged hadron transverse momentum spectra in d+Au collisions at sqrt(s_NN) = 200 GeV
• The RHIC Zero Degree Calorimeter
• High energy photons from passage of jets through quark gluon plasma
• Maximum Relative Strangeness Content in Heavy Ion Collisions Around 30 A.GeV
• Centrality Dependence of the Charged Particle Multiplicity near Mid-Rapidity in Au+Au Collisions at sqrt(s_NN) = 130 and 200 GeV
• Charged hadron transverse momentum distributions in Au+Au collisions at sqrt(s_NN) = 200 GeV
• Search for Proton Decay via p -> e+ pi0 in a Large Water Cherenkov Detector
• Phase transitions in the early and the present Universe
• Scaling of Charged Particle Production in d+Au Collisions at sqrt(s_NN) = 200 GeV
• Nuclear Effects on Hadron Production in d+Au and p+p Collisions at sqrt(s_NN)=200 GeV
• Centrality Dependence of the High p_T Charged Hadron Suppression in Au+Au collisions at sqrt(s_NN) = 130 GeV
• Centrality Dependence of Charged Particle Multiplicity at Mid-Rapidity in Au+Au Collisions at sqrt(s_NN) = 130 GeV
• Cronin effect vs. geometrical shadowing in d+Au collisions at RHIC
• Centrality dependence of charged hadron transverse momentum spectra in Au+Au collisions from sqrt(s_NN) = 62.4 to 200 GeV
• Final-State Interaction as the Origin of the Cronin Effect
• System size and centrality dependence of charged hadron transverse momentum spectra in Au+Au and Cu+Cu collisions at sqrt(s) = 62.4 and 200 GeV
• Pseudorapidity dependence of charged hadron transverse momentum spectra in d+Au collisions at sqrt sNN = 200 GeV
• Deuteron-Nucleus Collisions in a Multi-Phase Transport Model
• The PROOF Distributed Parallel Analysis Framework based on ROOT
• Hadrosynthesis at SPS and RHIC and the statistical model
• Energy Scan Program at the Cern SPS and An Observation of the Deconfinement Phase Transition in Nucleus--Nucleus Collisions
• Charged antiparticle to particle ratios near midrapidity in p+p collisions at sqrt(s_NN)=200 GeV
• Measuring centrality with slow protons in proton-nucleus collisions at the AGS
• Nuclear Shadowing in a Parton Recombination Model
• Centrality dependence of charged antiparticle to particle ratios near mid-rapidity in d+Au collisions at sqrt(s_NN)=200 GeV
• Search for Antimatter with the AMS Cosmic Ray Detector
• Particle production at very low and intermediate transverse momenta in d+Au and Au+Au collisions
• The structure of the nucleon