QCD anomalies in electromagnetic processes: A solution to the $γ\to3π$ puzzle

Fuente: arXiv
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Auteurs principaux: Xing, Zanbin, Dang, Hao, Sultan, M. Atif, Raya, Khépani, Chang, Lei
Format: Preprint
Publié: 2024
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author Xing, Zanbin
Dang, Hao
Sultan, M. Atif
Raya, Khépani
Chang, Lei
author_facet Xing, Zanbin
Dang, Hao
Sultan, M. Atif
Raya, Khépani
Chang, Lei
contents In this work, the $γ\to3π$ form factor is calculated within the Dyson-Schwinger equations framework using a contact interaction model within the so-called modified rainbow ladder truncation. The present calculation takes into account the pseudovector component in the pion Bethe-Salpeter amplitude (BSA) and $π-π$ scattering effects, producing a $γ\to3π$ anomaly which is $1+6\mathcal{R}_π^2$ larger than the low energy prediction. Here $\mathcal{R_π}$ is the relative ratio of the pseudovector and pseudoscalar components in the pion BSA; with our parameters input, this correction raises the $γ\to3π$ anomaly by around $10\%$. The main outcome of this work is the unveiling of the origin of such correction, which could be a possible explanation of the discrepancy between the existing experimental data and the low energy prediction. Moreover, it is highlighted how the magnitude of the anomaly is affected in effective theories that require an irremovable ultraviolet cutoff. We find that for both the anomalous processes $π\to2γ$ and $γ\to 3π$, the missing contribution to the anomaly can be compensated by the additional structures related with the quark anomalous magnetic moment.
format Preprint
id arxiv_https___arxiv_org_abs_2401_03169
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle QCD anomalies in electromagnetic processes: A solution to the $γ\to3π$ puzzle
Xing, Zanbin
Dang, Hao
Sultan, M. Atif
Raya, Khépani
Chang, Lei
High Energy Physics - Phenomenology
In this work, the $γ\to3π$ form factor is calculated within the Dyson-Schwinger equations framework using a contact interaction model within the so-called modified rainbow ladder truncation. The present calculation takes into account the pseudovector component in the pion Bethe-Salpeter amplitude (BSA) and $π-π$ scattering effects, producing a $γ\to3π$ anomaly which is $1+6\mathcal{R}_π^2$ larger than the low energy prediction. Here $\mathcal{R_π}$ is the relative ratio of the pseudovector and pseudoscalar components in the pion BSA; with our parameters input, this correction raises the $γ\to3π$ anomaly by around $10\%$. The main outcome of this work is the unveiling of the origin of such correction, which could be a possible explanation of the discrepancy between the existing experimental data and the low energy prediction. Moreover, it is highlighted how the magnitude of the anomaly is affected in effective theories that require an irremovable ultraviolet cutoff. We find that for both the anomalous processes $π\to2γ$ and $γ\to 3π$, the missing contribution to the anomaly can be compensated by the additional structures related with the quark anomalous magnetic moment.
title QCD anomalies in electromagnetic processes: A solution to the $γ\to3π$ puzzle
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2401.03169