HYDRO + JETS (HYDJET+ +) event generator for Pb+Pb collisions at LHC

L Bravina,J Crkovská,L Malinina,A Snigirev,E Zabrodin,B H Brusheim Johansson,E Nazarova,V Korotkikh,S Petrushanko,G Eyyubova,I Lokhtin

doi:10.1088/1742-6596/736/1/012024

Abstract

The Monte Carlo event generator HYDJET++ is one of the few generators, designed for the calculations of heavy-ion collisions at ultrarelativistic energies, which combine treatment of soft hydro-like processes with the description of jets traversing the hot and dense partonic medium. The model is employed to study the azimuthal anisotropy phenomena, dihadron angular correlations and event-by-event (EbyE) fluctuations of the anisotropic flow in Pb+Pb collisions at ^/snn = 2.76 TeV. The interplay of soft and hard processes describes the violation of the mass hierarchy of meson and baryon elliptic and triangular flows at pT > 2 GeV/c, the fall-off of the flow harmonics at intermediate transverse momenta, and the worsening of the number-of-constituent-quark (NCQ) scaling of elliptic/triangular flow at LHC compared to RHIC energies. The cross-talk of v2 and v3 leads to emergence of higher order harmonics in the model and to appearance of the ridge structure in dihadron angular correlations in a broad pseudorapidity range. HYDJET++ possesses also the dynamical EbyE fluctuations of the anisotropic flow. The model results agree well with the experimental data.

Highlights

HYDJET++ modelThe Monte Carlo event generator HYDJET++ (HYDrodynamics with JETs) [1] consists of two parts describing the soft and the hard processes, respectively
The number of produced jets in HYDJET++ is proportional to the number of binary nucleon-nucleon collisions at a given impact parameter and the integral cross section of the hard processes in NN collision with minimal transverse momentum transfer
In HYDJET++ these effects were studied in non-central heavy-ion collisions at RHIC and LHC energies in [14, 15] for the elliptic flow and in [16, 17] for the triangular flow, respectively

Summary

Introduction

HYDJET++ modelThe Monte Carlo event generator HYDJET++ (HYDrodynamics with JETs) [1] consists of two parts describing the soft and the hard processes, respectively. The cross-talk of elliptic and triangular harmonics leads to appearance of both even and odd higher harmonics of the anisotropic flow in the model because of the nonlinear contributions to vn from v2, v3 or their product v2v3.

Results

Conclusion