In medium static quark anti-quark potential from lattice QCD

Abstract

In this thesis we present recent progress in the quest to study the properties of the quark gluon plasma in relativistic heavy ion collisions through a better understanding of the binding of heavy quark and anti-quark pairs (quarkonium). We present two studies investigating the complex binding potential between heavy quarks using non-perturbative lattice QCD simulations and modern data analysis techniques that were contributed to and performed as a part of this PhD project. The first study utilizes state of the art simulations with 2+1 flavours of dynamical light HISQ quarks. This study revealed a complex potential with an unscreened real part. Its results were in stark contrast to previous studies on quenched and full QCD lattices which had all shown a complex potential with a screened real part. This unusual result motivated a second study, where we re-investigated the potential on high resolution quenched lattices to confirm their robustness using the same methods deployed in the full QCD study. We found that the analysis techniques applied to the raw correlators confirms previous results, i.e. resulting in a complex potential with a screened real part. Applying the same analysis after performing a recently proposed subtraction procedure leads instead to an unscreened potential akin to the first study on HISQ lattices.