Factorizing the position-space photon propagator in QED corrections to lattice QCD correlators

Fuente: arXiv
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Main Authors: Erb, Dominik, Meyer, Harvey B., Ottnad, Konstantin
Format: Preprint
Published: 2026
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author Erb, Dominik
Meyer, Harvey B.
Ottnad, Konstantin
author_facet Erb, Dominik
Meyer, Harvey B.
Ottnad, Konstantin
contents Electromagnetic corrections to the $n$-point functions of lattice QCD can be evaluated using a position-space photon propagator defined in infinite volume. Here we address the computational challenge arising from the volume-squared sum over the endpoints of the photon propagator. We consider a class of integral representations of the photon propagator that lead to a factorization of the two volume-sums, the Fourier representation being one instance thereof. An alternative choice is based on expressing the free scalar propagator as the autoconvolution of the corresponding five-dimensional propagator. We compare the performance of three different choices in the context of electromagnetic corrections to the hadronic vacuum polarization, on a gauge ensemble of size $48^3\times128$ with a pion mass of 286 MeV. As an outlook, we discuss more generally the factorization of sums over internal vertices, taking as an example the hadronic light-by-light contribution to the muon $(g-2)$.
format Preprint
id arxiv_https___arxiv_org_abs_2603_13086
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Factorizing the position-space photon propagator in QED corrections to lattice QCD correlators
Erb, Dominik
Meyer, Harvey B.
Ottnad, Konstantin
High Energy Physics - Lattice
Electromagnetic corrections to the $n$-point functions of lattice QCD can be evaluated using a position-space photon propagator defined in infinite volume. Here we address the computational challenge arising from the volume-squared sum over the endpoints of the photon propagator. We consider a class of integral representations of the photon propagator that lead to a factorization of the two volume-sums, the Fourier representation being one instance thereof. An alternative choice is based on expressing the free scalar propagator as the autoconvolution of the corresponding five-dimensional propagator. We compare the performance of three different choices in the context of electromagnetic corrections to the hadronic vacuum polarization, on a gauge ensemble of size $48^3\times128$ with a pion mass of 286 MeV. As an outlook, we discuss more generally the factorization of sums over internal vertices, taking as an example the hadronic light-by-light contribution to the muon $(g-2)$.
title Factorizing the position-space photon propagator in QED corrections to lattice QCD correlators
topic High Energy Physics - Lattice
url https://arxiv.org/abs/2603.13086