Lattice study of spin interactions between heavy quarks in the quark-gluon plasma

Dibyendu Bala; Olaf Kaczmarek; Sayantan Sharma; Swagatam Tah

Lattice study of spin interactions between heavy quarks in the quark-gluon plasma

High Energy Physics - Lattice 2026-07-23 v1 High Energy Physics - Phenomenology Nuclear Experiment Nuclear Theory

Authors: Dibyendu Bala , Olaf Kaczmarek , Sayantan Sharma , Swagatam Tah

Abstract

We calculate the spin-dependent potential, which is the $\mathcal{O}(1/M^2)$ correction term to the thermal potential between a static quark-antiquark pair within non-relativistic QCD. At leading order in hard thermal loop perturbation theory, we show that this spin-dependent potential has an imaginary part which is different in magnitude for pseudoscalar and vector quarkonium states. For the first time, we extract the imaginary part non-perturbatively using lattice techniques, in the deconfined phase of quenched QCD at $T\sim 470$ MeV, after performing a continuum estimation and subsequent renormalization. We have found that the spin-dependent potential in the quark-gluon plasma phase is complex, and its imaginary part has a remarkably significant contribution over the thermal static potential for charmonium states. Consequences of this thermal spin-dependent potential on the quarkonium spectral functions are also discussed.

Keywords

spin-dependent potential quark-gluon plasma lattice QCD heavy quarkonium thermal potential non-relativistic QCD

Cite

@article{arxiv.2607.21729,
  title  = {Lattice study of spin interactions between heavy quarks in the quark-gluon plasma},
  author = {Dibyendu Bala and Olaf Kaczmarek and Sayantan Sharma and Swagatam Tah},
  journal= {arXiv preprint arXiv:2607.21729},
  year   = {2026}
}