Abstract
Recent data on the high-p T pion nuclear modification factor, R AA (p T ), and its elliptic azimuthal asymmetry, v 2(p T ), from RHIC/BNL and LHC/CERN are analyzed in terms of a wide class of jet-energy loss models coupled to different (2+1)d transverse plus Bjorken expanding hydrodynamic fields. We test the consistency of each model by demanding a simultaneous account of the azimuthal, the transverse momentum, and the centrality dependence of the data at both 0.2 and 2.76 ATeV energies. We find a rather broad class of jet-energy independent energy-loss models dE/dx = κ(T)x z T 2+z ζ q that, when coupled to bulk constrained temperature fields T(x, t), can account for the current data at the χ 2 /d.o.f. < 2 level with different temperature-dependent jet-medium couplings, κ(T), and path-length dependence exponents 0 ≤ z ≤ 2. We extend previous studies by including a generic term, 0 < ζ q < 2 + q, to test different scenarios of energy-loss fluctuations. While a previously proposed AdS/CFT jet-energy loss model with a temperature-independent jet-medium coupling as well as a near-T c dominated, pQCD-inspired energy-loss scenario are shown to be inconsistent with the LHC data, once the parameters are constrained by fitting to RHIC results, we find several new solutions with a temperature-dependent κ(T). We conclude that the current level of statistical and systematic uncertainties of the measured data does not allow a constraint on the path-length exponent z to a range narrower than [0 − 2].
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M. Gyulassy, I. Vitev, X.-N. Wang and B.-W. Zhang, Jet quenching and radiative energy loss in dense nuclear matter, in Quark gluon plasma, R.C. Hwa et al. eds., pg. 123, nucl-th/0302077 [INSPIRE].
M. Gyulassy, Theory of high-energy A+A at RHIC., Lect. Notes Phys. 583 (2002) 37 [nucl-th/0106072] [INSPIRE].
I. Vitev and M. Gyulassy, High p T tomography of d + Au and Au+Au at SPS, RHIC and LHC, Phys. Rev. Lett. 89 (2002) 252301 [hep-ph/0209161] [INSPIRE].
M. Gyulassy, P. Levai and I. Vitev, Reaction operator approach to nonAbelian energy loss, Nucl. Phys. B 594 (2001) 371 [nucl-th/0006010] [INSPIRE].
X.-N. Wang and M. Gyulassy, Gluon shadowing and jet quenching in A + A collisions at \( \sqrt{s}=200 \) GeV, Phys. Rev. Lett. 68 (1992) 1480 [INSPIRE].
(JET) Topical Collaboration on Jet and Electromagnetic Tomography, http://jet.lbl.gov/main.
H. Song and U.W. Heinz, Causal viscous hydrodynamics in 2+1 dimensions for relativistic heavy-ion collisions, Phys. Rev. C 77 (2008) 064901 [arXiv:0712.3715] [INSPIRE].
H. Song and U.W. Heinz, Multiplicity scaling in ideal and viscous hydrodynamics, Phys. Rev. C 78 (2008) 024902 [arXiv:0805.1756] [INSPIRE].
C. Shen, U. Heinz, P. Huovinen and H. Song, Radial and elliptic flow in Pb+Pb collisions at the Large Hadron Collider from viscous hydrodynamic, Phys. Rev. C 84 (2011) 044903 [arXiv:1105.3226] [INSPIRE].
Z. Qiu, C. Shen and U. Heinz, Hydrodynamic elliptic and triangular flow in Pb-Pb collisions at \( \sqrt{s}=2.76 A \) TeV, Phys. Lett. B 707 (2012) 151 [arXiv:1110.3033] [INSPIRE].
C. Shen, U. Heinz, P. Huovinen and H. Song, Systematic parameter study of hadron spectra and elliptic flow from viscous hydrodynamic simulations of Au+Au collisions at \( \sqrt{s_{NN}}=200 \) GeV, Phys. Rev. C 82 (2010) 054904 [arXiv:1010.1856] [INSPIRE].
M. Luzum and P. Romatschke, Conformal Relativistic Viscous Hydrodynamics: Applications to RHIC results at \( \sqrt{s_{NN}}=200 \) GeV, Phys. Rev. C 78 (2008) 034915 [Erratum ibid. C 79 (2009) 039903] [arXiv:0804.4015] [INSPIRE].
M. Luzum and P. Romatschke, Viscous Hydrodynamic Predictions for Nuclear Collisions at the LHC, Phys. Rev. Lett. 103 (2009) 262302 [arXiv:0901.4588] [INSPIRE].
M. Gyulassy, I. Vitev, X.-N. Wang and P. Huovinen, Transverse expansion and high p T azimuthal asymmetry at RHIC, Phys. Lett. B 526 (2002) 301 [nucl-th/0109063] [INSPIRE].
M. Gyulassy, I. Vitev and X.N. Wang, High p T azimuthal asymmetry in noncentral A + A at RHIC, Phys. Rev. Lett. 86 (2001) 2537 [nucl-th/0012092] [INSPIRE].
PHENIX collaboration, A. Adare et al., Neutral pion production with respect to centrality and reaction plane in Au+Au collisions at \( \sqrt{s_{NN}}=200 \) GeV, Phys. Rev. C 87 (2013) 034911 [arXiv:1208.2254] [INSPIRE].
ALICE collaboration, Centrality Dependence of Charged Particle Production at Large Transverse Momentum in Pb-Pb Collisions at \( \sqrt{s_{NN}}=2.76 \) TeV, Phys. Lett. B 720 (2013) 52 [arXiv:1208.2711] [INSPIRE].
ALICE collaboration, Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at \( \sqrt{s_{NN}}=2.76 \) TeV, Phys. Lett. B 719 (2013) 18 [arXiv:1205.5761] [INSPIRE].
CMS collaboration, Study of high-pT charged particle suppression in PbPb compared to pp collisions at \( \sqrt{s_{NN}}=2.76 \) TeV, Eur. Phys. J. C 72 (2012) 1945 [arXiv:1202.2554] [INSPIRE].
CMS collaboration, Measurement of the azimuthal anisotropy of neutral pions in PbPb collisions at \( \sqrt{s_{NN}}=2.76 \) TeV, Phys. Rev. Lett. 110 (2013) 042301 [arXiv:1208.2470] [INSPIRE].
ATLAS collaboration, Measurement of the azimuthal anisotropy for charged particle production in \( \sqrt{s_{NN}}=2.76 \) TeV lead-lead collisions with the ATLAS detector, Phys. Rev. C 86 (2012) 014907 [arXiv:1203.3087] [INSPIRE].
ATLAS collaboration, Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead-lead collisions at \( \sqrt{s_{NN}}=2.76 \) TeV with the ATLAS detector, Phys. Lett. B 707 (2012) 330 [arXiv:1108.6018] [INSPIRE].
J. Liao and E. Shuryak, Angular Dependence of Jet Quenching Indicates Its Strong Enhancement Near the QCD Phase Transition, Phys. Rev. Lett. 102 (2009) 202302 [arXiv:0810.4116] [INSPIRE].
X. Zhang and J. Liao, Hard Probe of Geometry and Fluctuations from RHIC to LHC, Phys. Rev. C 89 (2014) 014907 [arXiv:1208.6361] [INSPIRE].
X. Zhang and J. Liao, Event-by-event azimuthal anisotropy of jet quenching in relativistic heavy ion collisions, Phys. Rev. C 87, 044910 (2013) 044910 [arXiv:1210.1245] [INSPIRE].
B. Betz and M. Gyulassy, Azimuthal Jet Tomography of Quark Gluon Plasmas at RHIC and LHC, arXiv:1305.6458 [INSPIRE].
B. Betz and M. Gyulassy, Examining a reduced jet-medium coupling in Pb+Pb collisions at the Large Hadron Collider, Phys. Rev. C 86 (2012) 024903 [arXiv:1201.0281] [INSPIRE].
B. Betz, M. Gyulassy and G. Torrieri, Fourier Harmonics of High-pT Particles Probing the Fluctuating Intitial Condition Geometries in Heavy-Ion Collisions, Phys. Rev. C 84 (2011) 024913 [arXiv:1102.5416] [INSPIRE].
W.A. Horowitz and M. Gyulassy, The Surprising Transparency of the sQGP at LHC, Nucl. Phys. A 872 (2011) 265 [arXiv:1104.4958] [INSPIRE].
W.A. Horowitz and M. Gyulassy, Quenching and Tomography from RHIC to LHC, J. Phys. G 38 (2011) 124114 [arXiv:1107.2136] [INSPIRE].
W.A. Horowitz, Testing pQCD and AdS/CFT Energy Loss at RHIC and LHC, AIP Conf. Proc. 1441 (2012) 889 [arXiv:1108.5876] [INSPIRE].
A. Buzzatti and M. Gyulassy, A running coupling explanation of the surprising transparency of the QGP at LHC, Nucl. Phys. A 904-905 (2013) 779c [arXiv:1210.6417] [INSPIRE].
A. Buzzatti and M. Gyulassy, Jet Flavor Tomography of Quark Gluon Plasmas at RHIC and LHC, Phys. Rev. Lett. 108 (2012) 022301 [arXiv:1106.3061] [INSPIRE].
B.G. Zakharov, Nuclear modification factor for light and heavy flavors within pQCD and recent data from the LHC, JETP Lett. 96 (2013) 616 [arXiv:1210.4148] [INSPIRE].
B.G. Zakharov, Jet quenching with running coupling including radiative and collisional energy losses, JETP Lett. 88 (2008) 781 [arXiv:0811.0445] [INSPIRE].
B.G. Zakharov, Nuclear suppression of light hadrons and single electrons at the RHIC and LHC, J. Phys. G 40 (2013) 085003 [arXiv:1304.5742] [INSPIRE].
R.A. Lacey, N.N. Ajitanand, J.M. Alexander, J. Jia and A. Taranenko, Scaling patterns for the suppression of charged hadron yields in Pb + Pb collisions at \( \sqrt{s_{NN}}=2.76 \) TeV: Constraints on transport coefficients, arXiv:1202.5537 [INSPIRE].
S. Pal and M. Bleicher, Suppression of high transverse momenta hadrons in Pb+Pb collisions at LHC, Phys. Lett. B 709 (2012) 82 [arXiv:1201.2546] [INSPIRE].
J. Xu, A. Buzzatti and M. Gyulassy, Azimuthal jet flavor tomography with CUJET2.0 of nuclear collisions at RHIC and LHC, arXiv:1402.2956 [INSPIRE].
D. Molnar and D. Sun, High-pT suppression and elliptic flow from radiative energy loss with realistic bulk medium expansion, arXiv:1305.1046 [INSPIRE].
D. Molnar and D. Sun, Realistic medium-averaging in radiative energy loss, Nucl. Phys. A910-911 (2013) 486 [arXiv:1209.2430] [INSPIRE].
O. Kaczmarek, F. Karsch, F. Zantow and P. Petreczky, Static quark anti-quark free energy and the running coupling at finite temperature, Phys. Rev. D 70 (2004) 074505 [Erratum ibid. D 72 (2005) 059903] [hep-lat/0406036] [INSPIRE].
S.A. Bass et al., Systematic Comparison of Jet Energy-Loss Schemes in a realistic hydrodynamic medium, Phys. Rev. C 79 (2009) 024901 [arXiv:0808.0908] [INSPIRE].
C. Nonaka and S.A. Bass, Space-time evolution of bulk QCD matter, Phys. Rev. C 75 (2007) 014902 [nucl-th/0607018] [INSPIRE].
C. Marquet and T. Renk, Jet quenching in the strongly-interacting quark-gluon plasma, Phys. Lett. B 685 (2010) 270 [arXiv:0908.0880] [INSPIRE].
J. Jia, W.A. Horowitz and J. Liao, A study of the correlations between jet quenching observables at RHIC, Phys. Rev. C 84 (2011) 034904 [arXiv:1101.0290] [INSPIRE].
J. Jia and R. Wei, Dissecting the role of initial collision geometry for jet quenching observables in relativistic heavy ion collisions, Phys. Rev. C 82 (2010) 024902 [arXiv:1005.0645] [INSPIRE].
T. Renk, Constraining the Physics of Jet Quenching, Phys. Rev. C 85 (2012) 044903 [arXiv:1112.2503] [INSPIRE].
T. Renk et al., Systematics of parton-medium interaction from RHIC to LHC, J. Phys. G 38 (2011)124089 [arXiv:1106.2392] [INSPIRE].
T. Renk, H. Holopainen, R. Paatelainen and K.J. Eskola, Systematics of the charged-hadron P T spectrum and the nuclear suppression factor in heavy-ion collisions from \( \sqrt{s}=200 \) GeV to \( \sqrt{s}=2.76 \) TeV, Phys. Rev. C 84 (2011) 014906 [arXiv:1103.5308] [INSPIRE].
X.-F. Chen, T. Hirano, E. Wang, X.-N. Wang and H. Zhang, Suppression of high p T hadrons in Pb + Pb Collisions at LHC, Phys. Rev. C 84 (2011) 034902 [arXiv:1102.5614] [INSPIRE].
H. Niemi, K.J. Eskola and P.V. Ruuskanen, Elliptic flow in nuclear collisions at the Large Hadron Collider, Phys. Rev. C 79 (2009) 024903 [arXiv:0806.1116] [INSPIRE].
R.J. Fries and R. Rodriguez, Event-by-Event Jet Quenching and Higher Fourier Moments of Hard Probes, Nucl. Phys. A 855 (2011) 424 [arXiv:1012.3950] [INSPIRE].
R. Baier, A.H. Mueller and D. Schiff, How does transverse (hydrodynamic) flow affect jet-broadening and jet-quenching?, Phys. Lett. B 649 (2007) 147 [nucl-th/0612068] [INSPIRE].
M. Djordjevic and M. Gyulassy, Heavy quark radiative energy loss in QCD matter, Nucl. Phys. A 733 (2004) 265 [nucl-th/0310076] [INSPIRE].
S. Wicks, W. Horowitz, M. Djordjevic and M. Gyulassy, Elastic, inelastic and path length fluctuations in jet tomography, Nucl. Phys. A 784 (2007) 426 [nucl-th/0512076] [INSPIRE].
A. Ficnar, J. Noronha and M. Gyulassy, Falling Strings and Light Quark Jet Quenching at LHC, Nucl. Phys. A 910-911 (2013) 252 [arXiv:1208.0305] [INSPIRE].
S.S. Gubser, D.R. Gulotta, S.S. Pufu and F.D. Rocha, Gluon energy loss in the gauge-string duality, JHEP 10 (2008) 052 [arXiv:0803.1470] [INSPIRE].
P.M. Chesler, K. Jensen, A. Karch and L.G. Yaffe, Light quark energy loss in strongly-coupled N = 4 supersymmetric Yang-Mills plasma, Phys. Rev. D 79 (2009) 125015 [arXiv:0810.1985] [INSPIRE].
A. Ficnar, AdS/CFT Energy Loss in Time-Dependent String Configurations, Phys. Rev. D 86 (2012) 046010 [arXiv:1201.1780] [INSPIRE].
A. Ficnar, S.S. Gubser and M. Gyulassy, Shooting String Holography of Jet Quenching at RHIC and LHC, arXiv:1311.6160 [INSPIRE].
A. Ficnar, S.S. Gubser and M. Gyulassy, Holographic light quark jet quenching at RHIC and LHC via the shooting strings, arXiv:1404.0935 [INSPIRE].
M. Mia, F. Chen, K. Dasgupta, P. Franche and S. Vaidya, Non-Extremality, Chemical Potential and the Infrared limit of Large-N Thermal QCD, Phys. Rev. D 86 (2012) 086002 [arXiv:1202.5321] [INSPIRE].
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Betz, B., Gyulassy, M. Constraints on the path-length dependence of jet quenching in nuclear collisions at RHIC and LHC. J. High Energ. Phys. 2014, 90 (2014). https://doi.org/10.1007/JHEP08(2014)090
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DOI: https://doi.org/10.1007/JHEP08(2014)090