Bottomonium above deconfinement in lattice nonrelativistic QCD

TL;DR

This study investigates how bottomonium states behave at high temperatures above the deconfinement transition using lattice QCD, revealing that the $$ remains stable while $_b$ transitions to free-like behavior near twice the critical temperature.

Contribution

It introduces a lattice nonrelativistic QCD approach to analyze bottomonium properties across a range of high temperatures, highlighting differential thermal responses of $$ and $_b$ states.

Findings

$$ is insensitive to temperature up to 2.1 $T_c$

$_b$ shows a transition to free dynamics near 2 $T_c$

Provides insight into quarkonium behavior in quark-gluon plasma

Abstract

We study the temperature dependence of bottomonium for temperatures in the range $0.4 T_c < T < 2.1 T_c$, using nonrelativistic dynamics for the bottom quark and full relativistic lattice QCD simulations for $N_f=2$ light flavors on a highly anisotropic lattice. We find that the $\Upsilon$ is insensitive to the temperature in this range, while the $\chi_b$ propagators show a crossover from the exponential decay characterizing the hadronic phase to a power-law behaviour consistent with nearly-free dynamics at $T \simeq 2 T_c$.