Lattice NRQCD study on in-medium bottomonium spectra using a novel Bayesian reconstruction approach

TL;DR

This study investigates how bottomonium states are affected by the hot medium created in heavy-ion collisions, using lattice QCD and a new Bayesian method to extract spectral functions, revealing that these states survive up to 249 MeV.

Contribution

It introduces a novel Bayesian spectral reconstruction approach applied to lattice NRQCD data, improving the accuracy of in-medium bottomonium spectral function analysis.

Findings

Ground states of bottomonium survive up to 249 MeV.

New Bayesian method yields higher spectral reconstruction accuracy.

Provides upper limits on in-medium mass and width modifications.

Abstract

We present recent results on the in-medium modification of S- and P-wave bottomonium states around the deconfinement transition. Our study uses lattice QCD with $N_f=2+1$ light quark flavors to describe the non-perturbative thermal QCD medium between $140$MeV$<T<249$MeV and deploys lattice regularized non-relativistic QCD (NRQCD) effective field theory to capture the physics of heavy quark bound states immersed therein. The spectral functions of the $^3S_1$ $(\Upsilon)$ and $^3P_1$ $(\chi_{b1})$ bottomonium states are extracted from Euclidean time Monte Carlo simulations using a novel Bayesian prescription, which provides higher accuracy than the Maximum Entropy Method. Based on a systematic comparison of interacting and free spectral functions we conclude that the ground states of both the S-wave $(\Upsilon)$ and P-wave $(\chi_{b1})$ channel survive up to $T=249$MeV. Stringent upper limits on the size of the in-medium modification of bottomonium masses and widths are provided.