Recent Heavy Ion Results with the ATLAS Detector at the LHC

Abstract

Results are presented from the ATLAS collaboration from the 2010 LHC heavy ion run, during which nearly 10 inverse microbarns of luminosity were delivered. Soft physics results include charged particle multiplicities and collective flow. The charged particle multiplicity, which tracks initial state entropy production, increases by a factor of two relative to the top RHIC energy, with a centrality dependence very similar to that already measured at RHIC. Measurements of elliptic flow out to large transverse momentum also show similar results to what was measured at RHIC, but no significant pseudorapidity dependence. Extensions of these measurements to higher harmonics have also been made, and can be used to explain structures in the two-particle correlation functions that had long been attributed to jet-medium interactions. New hard probe measurements include single muons, jets and high $p_T$ hadrons. Single muons at high momentum are used to extract the yield of $W^{\pm }$ bosons and are found to be consistent within statistical uncertainties with binary collision scaling. Conversely, jets are found to be suppressed in central events by a factor of two relative to peripheral events, with no significant dependence on the jet energy. Fragmentation functions are also found to be the same in central and peripheral events. Finally, charged hadrons have been measured out to 30 GeV, and their centrality dependence relative to peripheral events is similar to that found for jets.

9 pages, 9 figures, proceedings for Quark Matter 2011, Annecy, France, May 23-28, 2011

References in corpus (10)

• Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV
• Collision geometry fluctuations and triangular flow in heavy-ion collisions
• Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at sqrt(S(NN))= 2.76 TeV with the ATLAS Detector at the LHC
• Centrality dependence of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Measurement of the centrality dependence of J/ψ yields and observation of Z production in lead-lead collisions with the ATLAS detector at the LHC
• Azimuthal anisotropy of neutral pion production in Au+Au collisions at sqrt(s_NN) = 200 GeV: Path-length dependence of jet quenching and the role of initial geometry
• Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter
• Measurement of Jets and Jet Suppression in sqrt(s_NN)=2.76 TeV Lead-Lead Collisions with the ATLAS detector at the LHC
• Centrality dependence of charged particle spectra and RCP in Pb+Pb collisions at \sqrt{s_{NN}}=2.76TeV with the ATLAS detector at the LHC

Cited by in corpus (18)

• First Results from Pb+Pb collisions at the LHC
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• Viscous photons in relativistic heavy ion collisions
• High multiplicity pp events and J/ψ production at LHC
• Collision Energy Dependence of Viscous Hydrodynamic Flow in Relativistic Heavy-Ion Collisions
• Quenching and Tomography from RHIC to LHC
• Examining a reduced jet-medium coupling in Pb+Pb collisions at the Large Hadron Collider
• The performance of the jet trigger for the ATLAS detector during 2011 data taking
• Shining a Gluon Beam Through Quark-Gluon Plasma
• Local Multiplicity Fluctuations as a Signature of Critical Hadronization at LHC
• Resonance Decay Contributions to Higher-Order Anisotropic Flow Coefficients
• Recent experimental results from the relativistic heavy-ion collisions at LHC and RHIC
• Exploring Anisotropic flow via the Boltzmann Transport Equation Employing the Tsallis Blast Wave Description at LHC energies
• The high energy frontier of ultrarelativistic nucleus-nucleus collisions
• Quenching of hadron and photon spectra in heavy-ion collisions from RHIC to LHC
• NLO analysis of inclusive jet, tagged jet and di-jet production in Pb+Pb collisions at the LHC
• Calculating Jet $v_n$ and the Event Plane in the Presence of a Jet
• Sound Propagation on Top of the Fireball