# High statistics study of in-medium S- and P-wave quarkonium states in lattice Non-relativistic QCD

## TL;DR

This study uses lattice NRQCD to analyze in-medium properties of quarkonium states, revealing sequential melting patterns and survival temperatures, thus providing first-principles insights into quarkonium suppression in hot QCD media.

## Contribution

It presents high-precision lattice NRQCD results on quarkonium spectral functions, including in-medium mass shifts and survival temperatures, with improved Bayesian reconstruction techniques.

## Key findings

- Upsilon features may survive up to ~400 MeV
- Chi_b signal disappears around 270 MeV
- Chi_c melts below 190 MeV, J/Ψ survives up to 245 MeV

## Abstract

Many measurements of quarkonium suppression at the LHC, e.g. the nuclear modification factor $R_{AA}$ of $J/\Psi$, are well described by a multitude of different models. Thus pinpointing the underlying physics aspects is difficult and guidance based on first principles is needed. Here we present the current status of our ongoing high precision study of in-medium spectral properties of both bottomonium and charmonium based on NRQCD on the lattice. This effective field theory allows us to capture the physics of quarkonium without modeling assumptions in a thermal QCD medium. In our study a first principles and realistic description of the QCD medium is provided by state-of-the-art lattices of the HotQCD collaboration at almost physical pion mass. Our updated results corroborate a picture of sequential modification of states with respect to their vacuum binding energy. Using a novel low-gain variant of the Bayesian BR method for reconstructing spectral functions we find that remnant features of the Upsilon may survive up to $T\sim400$MeV, while the $\chi_b$ signal disappears around $T\sim270$MeV. The $c\bar{c}$ analysis hints at melting of $\chi_c$ below $T\sim190$MeV while some $J/\Psi$ remnant feature might survive up to $T\sim245$MeV. An improved understanding of the numerical artifacts in the Bayesian approach and the availability of increased statistics have made possible a first quantitative study of the in-medium ground state masses, which tend to lower values as $T$ increases, consistent with lattice potential based studies.