Heavy quarkonia at high temperature

Abstract

We present a new method to study the properties of heavy quarks at finite temperature. It combines non-relativistic QCD with an improved gluonic action on anisotropic lattices. The efficiency of the approach is demonstrated by the first non-perturbative calculation of the temperature dependence of low-lying quarkonium "pole" masses. For ground state meson masses in the region between charmonium and bottomonium we find only very little variation up to our highest temperature which corresponds to T ≈ 1.2 T c while first excited states indicate a large mass shift.

Lattice QCD at Finite Temperature and Density

“…Anisotropic lattices in combination with NRQCD have also been used to analyse thermal effects on heavy quark bound states [35]. Large mass shifts have been observed for the first excited states.…”

O(a)-improved quark action on anisotropic lattices and perturbative renormalization of heavy-light currents

“…This approach is especially effective when the signal-to-noise ratio deteriorates quickly, as, for example, in the case of glueballs [ 2]. The better signal-to-noise ratio is beneficial also for heavy quark systems [ 3]. In addition, it is hoped that the anisotropy can be exploited to reduce lattice artifacts [ 4], which are a special concern with heavy quarks.…”

Bottomonium above deconfinement from lattice non-relativistic QCD

“…As explained below, the use of NRQCD is a controlled approach which avoids many of the unwanted systematic effects encountered when using relativistic dynamics for bottomonium at nonzero temperature [15][16][17]. An early study of bottomonium at nonzero temperature using NRQCD (on a quenched background for the 1 S 0 and 3 S 1 channels only) can be found in the pioneering work [18].…”