Probing the photon emissivity of the quark-gluon plasma without an inverse problem in lattice QCD Article Swipe

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Physics Omega Lattice QCD Inverse Particle physics Quantum chromodynamics Emissivity Photon Quark–gluon plasma Fermion Lattice (music) Quark Plasma Sigma Gluon Quantum electrodynamics Quantum mechanics Geometry Mathematics Acoustics

Marco Cè , Tim Harris , Ardit Krasniqi , Harvey B. Meyer , Csaba Török ·

YOU? · · 2024 · Open Access · · DOI: https://doi.org/10.3929/ethz-b-000655753 · OA: W4386876234

The thermal photon emissivity of the quark-gluon plasma is determined by the in-medium spectral function of the electromagnetic current at lightlike kinematics, $σ(ω)$. In this work, we present the first lattice QCD results on moments of $σ(ω)/ω$, defined by the weight function $1/(ω^2+ (2πT n)^2)$, $n\in\mathbb{Z}$ and computed without encountering an inverse problem. We employ two dynamical flavours of O($a$)-improved Wilson fermions at a temperature $T\approx 250\;$MeV and perform the continuum limit. We compare our results for the first two moments to those obtained dispersively by integrating over the spectral function computed at weak coupling by Arnold, Moore and Yaffe.