Decomposition of the axial-vector current in a finite box

Fuente: arXiv
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Auteurs principaux: Hermsen, Felix, Lutz, Matthias F. M., Timmermans, Rob G. E.
Format: Preprint
Publié: 2026
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author Hermsen, Felix
Lutz, Matthias F. M.
Timmermans, Rob G. E.
author_facet Hermsen, Felix
Lutz, Matthias F. M.
Timmermans, Rob G. E.
contents We consider the matrix element of the axial-vector current between two nucleon states in a finite box. Starting from the chiral Lagrangian density with nucleon and $Δ$-isobar degrees of freedom, we study the finite-volume effects at the one-loop level. We show that the standard decomposition into the axial-vector and pseudoscalar form factor is incomplete in a finite box. We derive expressions for the complete set of form factors at one loop. We verify that the axial Ward identity holds in the chiral limit. Selected numerical results are shown for two flavor-SU(2) lattice ensembles. Sizable finite-volume effects are observed, with an important role for the $Δ$-isobar. We discuss the implications of our results for lattice studies of the axial-vector current. We conclude that full finite-box results are crucial for a precise determination of the form factors.
format Preprint
id arxiv_https___arxiv_org_abs_2606_02243
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Decomposition of the axial-vector current in a finite box
Hermsen, Felix
Lutz, Matthias F. M.
Timmermans, Rob G. E.
High Energy Physics - Lattice
High Energy Physics - Phenomenology
We consider the matrix element of the axial-vector current between two nucleon states in a finite box. Starting from the chiral Lagrangian density with nucleon and $Δ$-isobar degrees of freedom, we study the finite-volume effects at the one-loop level. We show that the standard decomposition into the axial-vector and pseudoscalar form factor is incomplete in a finite box. We derive expressions for the complete set of form factors at one loop. We verify that the axial Ward identity holds in the chiral limit. Selected numerical results are shown for two flavor-SU(2) lattice ensembles. Sizable finite-volume effects are observed, with an important role for the $Δ$-isobar. We discuss the implications of our results for lattice studies of the axial-vector current. We conclude that full finite-box results are crucial for a precise determination of the form factors.
title Decomposition of the axial-vector current in a finite box
topic High Energy Physics - Lattice
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2606.02243