$R$-matrix type parametrization of the Jost function for extracting the resonance parameters from scattering data

Fuente: arXiv
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Main Authors: Vaandrager, P., Lekala, M. L., Rakityansky, S. A.
Format: Preprint
Published: 2025
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author Vaandrager, P.
Lekala, M. L.
Rakityansky, S. A.
author_facet Vaandrager, P.
Lekala, M. L.
Rakityansky, S. A.
contents A new method is proposed for fitting non-relativistic binary-scattering data and for extracting the parameters of possible quantum resonances in the compound system that is formed during the collision. The method combines the well-known $R$-matrix approach with the analysis based on the semi-analytic representation of the Jost functions. It is shown that such a combination has the advantages of both these approaches, namely, the number of the fitting parameters remains relatively small (as for the $R$-matrix approach) and the proper analytic structure of the $S$-matrix is preserved (as for the Jost function method). It is also shown that the new formalism, although closely related to the $R$-matrix method, has the benefit of no dependence on an arbitrary channel radius. The efficiency and accuracy of the proposed method are tested using a model single-channel potential. Artificial ``experimental'' data generated with this potential are fitted, and its known resonances are successfully recovered as zeros of the Jost function on the appropriate sheet of the Riemann surface of the energy.
format Preprint
id arxiv_https___arxiv_org_abs_2504_11129
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle $R$-matrix type parametrization of the Jost function for extracting the resonance parameters from scattering data
Vaandrager, P.
Lekala, M. L.
Rakityansky, S. A.
Quantum Physics
Nuclear Theory
A new method is proposed for fitting non-relativistic binary-scattering data and for extracting the parameters of possible quantum resonances in the compound system that is formed during the collision. The method combines the well-known $R$-matrix approach with the analysis based on the semi-analytic representation of the Jost functions. It is shown that such a combination has the advantages of both these approaches, namely, the number of the fitting parameters remains relatively small (as for the $R$-matrix approach) and the proper analytic structure of the $S$-matrix is preserved (as for the Jost function method). It is also shown that the new formalism, although closely related to the $R$-matrix method, has the benefit of no dependence on an arbitrary channel radius. The efficiency and accuracy of the proposed method are tested using a model single-channel potential. Artificial ``experimental'' data generated with this potential are fitted, and its known resonances are successfully recovered as zeros of the Jost function on the appropriate sheet of the Riemann surface of the energy.
title $R$-matrix type parametrization of the Jost function for extracting the resonance parameters from scattering data
topic Quantum Physics
Nuclear Theory
url https://arxiv.org/abs/2504.11129