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Main Authors: Hüsken, Nils, Swanson, Eric S., Szczepaniak, Adam
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.09844
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author Hüsken, Nils
Swanson, Eric S.
Szczepaniak, Adam
author_facet Hüsken, Nils
Swanson, Eric S.
Szczepaniak, Adam
contents The modeling of coupled-channel effects has become increasingly important due to the availability of highly precise data for a large variety of hadronic (re)scattering processes. The K-matrix is a powerful, yet comparatively simple, method to describe scattering amplitudes, including coupled-channel effects, with the aim to interpret experimental data. Throughout the literature, a range of dispersive and nondispersive K-matrix methods are employed. Here, we compare the dispersive and nondispersive formulations in the context of the N/D method. It is shown that the methods are equivalent in the physical region under K-matrix reparameterization. Differences away from the physical region are examined. Applications to synthetic data are used to illustrate the effects of model choices concerning form factors and the application of dispersion relations, with the goal of clarifying best practices. We find no clear preference with regards to dispersive modeling. In contrast, we find that interpretational ambiguity of the bare model parameters -- and even of the form of the bare model -- is endemic, and recommend a thorough sampling of data and model spaces to assess conclusion robustness.
format Preprint
id arxiv_https___arxiv_org_abs_2601_09844
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On Dispersive and Nondispersive K-matrix Formalisms
Hüsken, Nils
Swanson, Eric S.
Szczepaniak, Adam
High Energy Physics - Phenomenology
High Energy Physics - Experiment
The modeling of coupled-channel effects has become increasingly important due to the availability of highly precise data for a large variety of hadronic (re)scattering processes. The K-matrix is a powerful, yet comparatively simple, method to describe scattering amplitudes, including coupled-channel effects, with the aim to interpret experimental data. Throughout the literature, a range of dispersive and nondispersive K-matrix methods are employed. Here, we compare the dispersive and nondispersive formulations in the context of the N/D method. It is shown that the methods are equivalent in the physical region under K-matrix reparameterization. Differences away from the physical region are examined. Applications to synthetic data are used to illustrate the effects of model choices concerning form factors and the application of dispersion relations, with the goal of clarifying best practices. We find no clear preference with regards to dispersive modeling. In contrast, we find that interpretational ambiguity of the bare model parameters -- and even of the form of the bare model -- is endemic, and recommend a thorough sampling of data and model spaces to assess conclusion robustness.
title On Dispersive and Nondispersive K-matrix Formalisms
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2601.09844