Clint Young

Extracting the jet transport coefficient from jet quenching in high-energy heavy-ion collisions

Karen M. Burke, Alessandro Buzzatti, 3 Ningbo Chang, 5 Charles Gale, Miklos Gyulassy, Ulrich Heinz, Sangyong Jeon, Abhijit Majumder, Berndt Müller, Guang-You Qin, 1 Björn Schenke, Chun Shen, Xin-Nian Wang, 2 Jiechen Xu, Clint Young, and Hanzhong Zhang Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, USA Nuclear Science Division, MS 70R0319, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Department of Physics, Columbia University, New York 10027, USA School of Physics, Shandong University, Jinan, Shandong 250100, China Institute of Particle Physics and Key Laboratory of Quarks and Lepton Physics (MOE), Central China Normal University, Wuhan 430079, China Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8, Canada Department of Physics, The Ohio State University, Ohio 43210, USA Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA

Dijet asymmetry at the energies available at the CERN Large Hadron Collider

The martini numerical simulation allows for direct comparison of theoretical model calculations and the latest results for dijet asymmetry from the ATLAS and CMS collaborations. In this paper, partons are simulated as undergoing radiative and collisional processes throughout the evolution of central lead-lead collisions at the Large Hadron Collider. Using hydrodynamical background evolution determined by a simulation which fits well with the data on charged particle multiplicities from ALICE and a value of αs ≈ 0.25 − 0.3, the dijet asymmetry is found to be consistent with partonic energy loss in a hot, strongly-interacting medium. ∗Electronic address: clinty@physics.mcgill.ca †Electronic address: bschenke@quark.phy.bnl.gov ‡Electronic address: jeon@physics.mcgill.ca §Electronic address: gale@physics.mcgill.ca 1 ar X iv :1 10 3. 57 69 v2 [ nu cl -t h] 2 J un 2 01 1

Viscous photons in relativistic heavy ion collisions

Theoretical studies of the production of real thermal photons in relativistic heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are performed. The space-time evolution of the colliding system is modelled using MUSIC, a 3+1D relativistic hydrodynamic simulation, using both its ideal and viscous versions. The inclusive spectrum and its azimuthal angular anisotropy are studied separately, and the relative contributions of the different photon sources are highlighted. It is shown that the photon v2 coefficient is especially sensitive to the details of the microscopic dynamics like the equation of state, the ratio of shear viscosity over entropy density, eta/s, and to the morphology of the initial state.

Dilepton emission in high-energy heavy-ion collisions with viscous hydrodynamics

The invariant mass spectrum and the elliptic flow of lepton pairs produced in relativistic heavy-ion collisions at RHIC are studied with viscous hydrodynamics. The effects of viscous corrections on dilepton observables are explored. The lepton pairs originating from charm quarks evolving in the viscous background are seen to be a good probe of quark energy loss and gain, as quantified by the dilepton spectrum and by the dilepton elliptic flow.

MARTINI event generator for heavy quarks: Initialization, parton evolution, and hadronization

We present additions to the martini event generator for examining heavy quarks and quarkonia in heavy-ion collisions. All stages of a heavy-ion collision affect the observables associated with heavy quarks: the initial phase space of the heavy quarks are sampled with pythia8.1, the heavy quarks are evolved using Langevin dynamics and a 3+1-dimensional hydrodynamical description of the heavy-ion collision, and are fragmented and hadronized using a modified version of the color evaporation model that takes into account non-trivial evolution in position space, as well as the possibility of recombinant quarkonium production in heavy-ion collisions. We use this to re-examine the production of quarkonium at RHIC, and anticipating vertex detection we predict yields of Bc mesons at RHIC and the LHC. ∗Electronic address: clinty@physics.mcgill.ca †Electronic address: bschenke@quark.phy.bnl.gov ‡Electronic address: jeon@physics.mcgill.ca §Electronic address: gale@physics.mcgill.ca 1 ar X iv :1 11 1. 06 47 v1 [ nu cl -t h] 2 N ov 2 01 1

Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations

We match three hadronic equations of state at low energy densities to a perturbatively computed equation of state of quarks and gluons at high energy densities. One of them includes all known hadrons treated as point particles, which approximates attractive interactions among hadrons. The other two include, in addition, repulsive interactions in the form of excluded volumes occupied by the hadrons. A switching function is employed to make the crossover transition from one phase to another without introducing a thermodynamic phase transition. A chi-square fit to accurate lattice calculations with temperature

Numerical integration of thermal noise in relativistic hydrodynamics

100 < T < 1000

MUSIC with the UrQMD Afterburner

MeV determines the parameters. These parameters quantify the behavior of the QCD running gauge coupling and the hard core radius of protons and neutrons, which turns out to be

Causal baryon diffusion and colored noise

0.62 \pm 0.04

Dissipative effects on quarkonium spectral functions

fm. The most physically reasonable models include the excluded volume effect. Not only do they include the effects of attractive and repulsive interactions among hadrons, but they also achieve better agreement with lattice QCD calculations of the equation of state. The equations of state constructed in this paper do not result in a phase transition, at least not for the temperatures and baryon chemical potentials investigated. It remains to be seen how well these equations of state will represent experimental data on high energy heavy ion collisions when implemented in hydrodynamic simulations.