Measurement of azimuthal flow of soft and high-pT charged particles in 5.02 TeV Pb+Pb collisions with the ATLAS detector

Klaudia Burka

doi:10.1016/j.nuclphysbps.2017.05.103

Abstract

The experimental data collected by the ATLAS experiment during the 2015 heavy ion LHC run offers new opportunities to study properties of Quark-Gluon Plasma at unprecedented high temperatures and densities. Study of the azimuthal anisotropy of produced particles not only constrains our understanding of initial conditions of nuclear collisions and soft particle collective dynamics, but also sheds light on jet-quenching phenomena via measurement of flow harmonics at high transverse momenta. A new ATLAS measurement of elliptic flow and higher-order Fourier harmonics of charged particles in Pb+Pb collisions at sNN=5.02 TeV in a wide range of transverse momenta, pseudorapidity (|η|<2.5) and collision centrality is presented. These measurements are based on the Scalar Product and Two Particle Correlation methods. The results obtained are compared with experimental results at lower collision energies.

Highlights

The Quark Gluon Plasma (QGP) is a hot and dense nuclear matter produced and probed in ultra-relativistic heavy ion collisions at RHIC and recently at the LHC
Good insight into properties of QGP, in particular, information on the equation of state or shear viscosity, is provided by studying the azimuthal anisotropies of charged particles produced in collisions
The measurements were mainly based on signals measured by the ATLAS [9] Inner Detector (ID) and Forward Calorimeter (FCal)

Summary

Introduction

The Quark Gluon Plasma (QGP) is a hot and dense nuclear matter produced and probed in ultra-relativistic heavy ion collisions at RHIC and recently at the LHC. A good insight into properties of QGP, in particular, information on the equation of state or shear viscosity, is provided by studying the azimuthal anisotropies of charged particles produced in collisions. The anisotropies arise due to the initial huge pressure gradients in the interacting region of the colliding nuclei These pressure gradients transform the initial spatial anisotropies of created matter into momentum anisotropies of the final state particle production [1, 2]. LHC experiments [6, 7] had extensively measured vn as a function of particle pseudorapidities (η), transverse momentum (pT ) and centrality of a collision, using the data collected during the first operation period of the LHC with the center of mass energy sNN = 2.76 TeV. Burka / Nuclear and Particle Physics Proceedings 00 (2016) 1–4 μb−1 and 22 μb−1 of integrated luminosity, respectively [8]

Events selections

Results

Summary