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  • Open Access

Probing how bright the quark-gluon plasma glows in lattice QCD

Ardit Krasniqi1,*, Marco Cè2,3, Tim Harris4, Renwick J. Hudspith5, and Harvey B. Meyer1,6

  • *Contact author: arkrasni@uni-mainz.de
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Phys. Rev. D 112, 074503 – Published 10 October, 2025

DOI: https://doi.org/10.1103/8dq9-q62p

Abstract

Determining the spectrum of photons emitted by the quark-gluon plasma nonperturbatively remains an open computational challenge. In this paper, we calculate two moments of that spectrum at a tem-perature T≈254  MeV, employing lattice QCD with two flavors of O(a)-improved Wilson fermions, without facing an inverse problem. Our central value for the difference of these two moments, which is sensitive to photon energies ω≳πT, is lower than, but compatible with that obtained by integrating the leading-order weak-coupling photon spectrum. This study informs the “direct photon puzzle” in heavy-ion collision phenomenology, where it has proved difficult to simultaneously explain the yield and azimuthal anisotropy of photons not originating from final-state hadronic decays.

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Phys. Rev. D 112, 074503– Published 10 October, 2025
  • Received 21 May 2025
  • Accepted 18 September 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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