Continuum extrapolation of quarkonium correlators at non-zero temperature

Heng-Tong Ding,Anna-Lena Kruse,Hiroshi Ohno,Hauke Sandmeyer,Olaf Kaczmarek,M Della Morte,P Fritzsch,E Gámiz Sánchez,C Pena Ruano

doi:10.1051/epjconf/201817507010

Abstract

In the investigation of in-medium modifications of quarkonia and for determining heavy quark diffusion coeffcients, correlation functions play a crucial role. For the first time we perform a continuum extrapolation of charmonium and bottomonium correlators in the vector channel based on non-perturbatively clover-improved Wilson fermions in quenched lattice QCD. Calculations were done at 4 different lattice spacings, spatial extents between 96 and 192, aspect ratio from 1/6 to 1/2, for 5 temperatures between T/Tc = 0:75 and T/Tc = 2:2. We interpolate between different quark masses to match to the same vector meson mass over different lattice setups. Afterwards we extrapolate the renormalized correlators to the continuum. While we find a strong temperature dependence for charmonium, bottomonium states are only slightly affected at higher temperatures.

Highlights

In the investigation of properties of the quark gluon plasma (QGP), which is created at heavy ion collisions, quarkonium bound states are of great interest
Due to the color Debye screening, these states are expected to melt at a certain dissolution temperature and, suppression of J/ψ yields at heavy ion collisions compared to p-p-collisions can be a signal for the existence of a quark gluon plasma [1]
With this method we are able to calculate the correlator for any arbitrary meson mass between charmonium and bottomonium and can retune the correlators for all lattice sizes after the actual computation of the correlator and, can compensate uncertainties that stem from slight errors in the tuning of the quark masses

Summary

Introduction

In the investigation of properties of the quark gluon plasma (QGP), which is created at heavy ion collisions, quarkonium bound states are of great interest. Measurements at RHIC and LHC revealed a non-zero elliptic flow for heavy quarks [8,9,10]. In [16] a continuum extrapolation for the heavy quark momentum diffusion coefficient based on a color electric correlator has been carried out. This approach is limited to the heavy quark mass limit and as this analysis is not based on meson correlators, in-medium properties of bound states cannot be extracted by this approach. We have carried out a continuum extrapolation for charmonium and bottomonium correlation functions in quenched lattice QCD. A similar analysis for light quarks can be found in [17, 18]

Meson correlation functions and the spectral function

Lattice setup

Interpolating to the same vector meson mass

Extrapolation to the continuum

Conclusion