Evolution of pi^0 suppression in Au+Au collisions from sqrt(s_NN) = 39 to 200 GeV

Abstract

Neutral-pion, pi^0, spectra were measured at midrapidity (|y|<0.35) in Au+Au collisions at sqrt(s_NN) = 39 and 62.4 GeV and compared to earlier measurements at 200 GeV in the 1<p_T<10 GeV/c transverse-momentum (p_T) range. The high-p_T tail is well described by a power law in all cases and the powers decrease significantly with decreasing center-of-mass energy. The change of powers is very similar to that observed in the corresponding p+p-collision spectra. The nuclear-modification factors (R_AA) show significant suppression and a distinct energy dependence at moderate p_T in central collisions. At high p_T, R_AA is similar for 62.4 and 200 GeV at all centralities. Perturbative-quantum-chromodynamics calculations that describe R_AA well at 200 GeV, fail to describe the 39 GeV data, raising the possibility that the relative importance of initial-state effects and soft processes increases at lower energies. A conclusion that the region where hard processes are dominant is reached only at higher p_T, is also supported by the x_T dependence of the x_T-scaling power-law exponent.

371 authors, 7 pages, 4 figures, and 1 table. v2 is the version accepted by Phys. Rev. Lett. with replacement of Fig. 1 as per Erratum PRL.125.049901. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.html

References in corpus (3)

• Glauber Modeling in High Energy Nuclear Collisions
• A light-cone wavefunction approach to open heavy flavor dynamics in QCD matter
• Scaling properties in bulk and p${}_{\mathrm{T}}$-dependent particle production near midrapidity in relativistic heavy ion collisions

Cited by in corpus (28)

• Review of Jet Measurements in Heavy Ion Collisions
• Open Heavy Flavor in QCD Matter and in Nuclear Collisions
• Neutral pion production at midrapidity in pp and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV
• Beam-energy and centrality dependence of direct-photon emission from ultra-relativistic heavy-ion collisions
• Nonequilibrium kinetic freeze-out properties in relativistic heavy ion collisions from energies employed at the RHIC beam energy scan to those available at the LHC
• Neutral pion and $\eta$ meson production at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV
• $\eta$ meson production of high-energy nuclear collisions at NLO
• Centrality dependence of inclusive prompt photon production in d+Au, Au+Au, p+Pb, and Pb+Pb collisions
• Scaling properties of fractional momentum loss of high-pT hadrons in nucleus-nucleus collisions at $\sqrt{s_{{}_{NN}}}$ from 62.4 GeV to 2.76 TeV
• Modifications of Heavy-Flavor Spectra in $\sqrt{s_{\mathrm{NN}}}=62.4\mathrm{GeV}$ Au-Au Collisions
• Highlights from BNL-RHIC 2011-2013
• Production of ${\pi }^0$ and $\eta$ mesons in U$+$U collisions at $\sqrt{s_{{}_{NN}}}=192$ GeV
• Neutral meson production in pp and Pb-Pb collisions at the LHC measured with ALICE
• Arguing on entropic and enthalpic first-order phase transitions in strongly interacting matter
• Elliptic Flow of Heavy-Flavor Decay Electrons in Au+Au Collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 27 and 54.4 GeV at RHIC
• Measurement of neutral mesons in pp and Pb-Pb collisions at mid-rapidity with ALICE
• Constraining input parameters of AMPT model with $\varphi$ meson production
• Considerations on the suppression of charged particles and ${\pi }^0$ in high energy heavy ion collisions
• Neutral meson production in pp and Pb-Pb collisions measured by ALICE at the LHC
• Hadronic matter at the edge: A survey of some theoretical approaches to the physics of the QCD phase diagram
• How do quarks and gluons lose energy in the QGP?
• Detail study of the medium created in Au+Au collisions with high $p_T$ probes by the PHENIX experiment at RHIC
• Neutral pion production in Au+Au collisions at RHIC
• Nucleon-Gold Collisions at 200 AGeV Using Tagged d+Au Interactions in PHOBOS
• Recent results on Bose-Einstein correlations by the PHENIX Experiment
• Study of the neutral mesons in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV in the ALICE experiment at LHC
• Profiling hot and dense nuclear medium with high transverse momentum hadrons produced in d+Au and Au+Au collisions by the PHENIX experiment at RHIC