Predictions for 5.023 TeV Pb + Pb collisions at the CERN Large Hadron Collider

Abstract

We compute predictions for various low-transverse-momentum bulk observables in √ s NN = 5.023 TeV Pb+Pb collisions at the CERN Large Hadron Collider (LHC) from the event-by-event next-to-leading-order perturbative-QCD + saturation + viscous hydrodynamics ("EKRT") model. In particular, we consider the centrality dependence of charged hadron multiplicity, flow coefficients of the azimuth-angle asymmetries, and correlations of event-plane angles. The centrality dependencies of the studied observables are predicted to be very similar to those at 2.76 TeV, and the magnitudes of the flow coefficients and event-plane angle correlations are predicted to be close to those at 2.76 TeV. The flow coefficients may, however, offer slightly more discriminating power on the temperature dependence of QCD matter viscosity than the 2.76 TeV measurements. Our prediction for the multiplicity in the 0-5 % centrality class, obtained using the two temperature-dependent shear-viscosity-to-entropy ratios that give the best overall fit to BNL Relativistic Heavy Ion Collider (RHIC) and LHC data is dN ch /dη| |η| 0.5 = 1876 . . . 2046. We also predict a power-law increase from 200 GeV Au+Au collisions at RHIC to 2.76 and 5.023 TeV Pb+Pb collisions at the LHC, dN ch /dη| |η| 0.5 ∝ s 0.164...0.174 .

Dynamical versus equilibrium properties of the QCD phase transition: A holographic perspective

“…Most relativistic hydrodynamic work demonstrates that the hadron gas region and the crossover region can be reasonably well-constrained by theory vs. experimental data comparisons. However, the high temperature region is exceedingly difficult to constrain in the same manner with current experimental data [114,115]. [113] involving comparisons of relativistic hydrodynamics calculations to experimental data.…”

Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions atsNN=5.02 TeV

“…The EKRT model [31,32] combines collinearly factorized next-to-leading-order pQCD minijet cross sections with a conjecture of gluon saturation to suppress soft parton production. Impact-parameter-dependent EPS09s parton distribution functions [40] are used.…”

Studies of three-particle correlations and reaction-plane correlators from STAR

“…They include 1) hydrodynamic simulations by Teaney and Yan [3,5], 2) the perturbative QCD+saturation+hydro based "EKRT" model [11] and 3) hydrodynamic simulations MUSIC [32] with IP-Glasma initial conditions [33]. In addition we also estimate the correlations from initial state geometry using Monte Carlo Glauber model by approximating C m,n,m+n = ε m ε n ε m+n cos(mΦ m + nΦ n − (m + n)Φ m+n ) , where ε n s and Φ n s are the initial eccentricities and the participant planes respectively.…”

“…However measurements at a single energy is not sufficient to constrain η/s (T ). LHC measurements are sensitive to the η/s at higher temperatures, meanwhile full constraint on η/s (T ) can only be achieved with complementary measurements of C m,n,m+n at RHIC [11,12,15,16]. In fact, measurements over the entire range of energy available under the Beam Energy Scan (BES) program at RHIC will be most preferable in this context.…”

“…Theoretical studies show that such an observable can probe non-linear hydrodynamic response and therefore become more sensitive to viscosity than individual flow harmonics v n [1][2][3][4][5][6][7][8][9][10]. Better sensitivity to viscous effects can be very useful towards more precise extraction of different transport parameters and possibly their temperature dependence by comparison to hydrodynamic simulations [11,12]. Measurements of event plane and flow harmonic correlations have been performed at LHC by ATLAS collaboration [13] and recently by ALICE collaboration [14].…”