Perturbative results of matrix elements of the axial current and their relation with the axial anomaly

Fuente: arXiv
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Autori principali: Castelli, Ignacio, Freese, Adam, Lorcé, Cédric, Metz, Andreas, Pasquini, Barbara, Rodini, Simone
Natura: Preprint
Pubblicazione: 2024
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author Castelli, Ignacio
Freese, Adam
Lorcé, Cédric
Metz, Andreas
Pasquini, Barbara
Rodini, Simone
author_facet Castelli, Ignacio
Freese, Adam
Lorcé, Cédric
Metz, Andreas
Pasquini, Barbara
Rodini, Simone
contents In the Standard Model of particle physics, the axial current is not conserved, due both to fermion masses and to the axial anomaly. Using perturbative quantum chromodynamics, we calculate matrix elements of the local and non-local axial current for a gluon target, clarifying their connection with the axial anomaly. In so doing, we also reconsider classic results obtained in the context of the nucleon spin sum rule as well as recent results for off-forward kinematics. An important role is played by the infrared regulator, for which we put a special emphasis on the nonzero quark mass. We highlight cancellations that take place between contributions from the axial anomaly and the quark mass, and we elaborate on the relation of those cancellations with the conservation of angular momentum.
format Preprint
id arxiv_https___arxiv_org_abs_2408_00554
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Perturbative results of matrix elements of the axial current and their relation with the axial anomaly
Castelli, Ignacio
Freese, Adam
Lorcé, Cédric
Metz, Andreas
Pasquini, Barbara
Rodini, Simone
High Energy Physics - Phenomenology
In the Standard Model of particle physics, the axial current is not conserved, due both to fermion masses and to the axial anomaly. Using perturbative quantum chromodynamics, we calculate matrix elements of the local and non-local axial current for a gluon target, clarifying their connection with the axial anomaly. In so doing, we also reconsider classic results obtained in the context of the nucleon spin sum rule as well as recent results for off-forward kinematics. An important role is played by the infrared regulator, for which we put a special emphasis on the nonzero quark mass. We highlight cancellations that take place between contributions from the axial anomaly and the quark mass, and we elaborate on the relation of those cancellations with the conservation of angular momentum.
title Perturbative results of matrix elements of the axial current and their relation with the axial anomaly
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2408.00554