High-order flow harmonics of identified hadrons in2.76ATeV Pb + Pb collisions

Abstract

Using iEBE-VISHNU hybrid model with the AMPT initial conditions, we study the higher order flow harmonics of identified hadrons in 2.76 A TeV Pb+Pb collisions. Comparison with the recent ALICE measurements at 20-30% centrality shows that our calculations nicely describe the data below 2 GeV, especially for the v2, v3 and v4 mass-orderings among pions, kaons and protons. We also extended the calculations to other centrality bins, which presents similar mass-ordering patterns for these flow harmonics as the ones observed at 20-30% centrality. In the later part of this article, we explore the development of vn mass ordering/splitting during the hadronic evolution through the comparison runs from iEBE-VISHNU hybrid model and pure hydrodynamics with different decoupling temperatures.

Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at s N N = 2.76 $$ \sqrt{s_{\mathrm{NN}}}=2.76 $$ TeV

“…Section 6.3 presents the mass dependence of v sub n (p T ) which is followed by a discussion about the scaling properties of different flow harmonics in different centrality intervals. In section 6.5, two models, namely iEBE-VISHNU [49] and A Multi Phase Transport model (AMPT) [50][51][52], are compared with the experimental measurements. Note that the same data will be shown in different representations in the following sections to highlight the various physics implications of the measurements.…”

“…Figures 11, 12 and 13 present the comparison between the ALICE measurements of v sub n and recent v n hydrodynamical calculations from [49]. These calculations are based on iEBE-VISHNU, an event-by-event version of the VISHNU hybrid model [54] which couples 2+1 dimensional viscous hydrodynamics (VISH2+1) to a hadron cascade model (UrQMD) [55] and uses a set of fluctuating initial conditions generated with AMPT.…”

Collective flow in 2.76 and 5.02 A TeV Pb + Pb collisions

“…Their simulations extracted a temperature-dependent specific shear viscosity η/s(T ), which is an approximately linear function with a minimum value close to the KSS bound near T c [51]. The early hydrodynamic and hybrid model simulations, using IP-Glasma [27], AMPT [26] or EKRT initial conditions [38], can also nicely fit the integrated and differential flow harmonics with a constant or temperature-dependent η/s, close to the KSS bound near T c . In fact, the flow harmonics v n are not sensitive to the details of the initial condition models as along as balanced initial eccentricities can be generated with some tunable parameters.…”

“…In the past few years, various flow observables have been extensively measured and studied in 2.76 A TeV Pb + Pb collisions, including the integrated and differential flow harmonics [20][21][22][23][24][25][26][27], the event-by-event v n distributions [27][28][29][30], the event-plane correlations [31][32][33][34][35],the correlations between different flow harmonics (symmetric cumulants) [35][36][37][38][39][40][41], the p T -and η-dependent de-correlations of the flow vector [42][43][44][45][46][47][48][49], etc. Many of these flow observables reflect the information on the event-by-event initial state fluctuations and the non-linear evolution of the system, which provide constraints for the initial condition models and the QGP transport coefficients.…”

A Review of Elliptic Flow of Light Nuclei in Heavy-Ion Collisions at RHIC and LHC Energies

“…Although mass ordering is a theoretical expectation from the hydrodynamical approach to heavy-ion collisions [76], coalescence formalism for light nuclei can also give rise to this effect. Recent studies using AMPT and VISHNU hybrid model suggest that mass ordering is also expected from transport approach to heavy-ion collisions [77][78][79].V 2 of light nuclei is negative for some collision energies as shown in Figure 1. This negative V 2 is expected to be the outcome of strong radial flow in heavy-ion collisions [80].…”