https://doi.org/10.1140/epjs/s11734-026-02150-z
Regular Article
Assessing the role of threshold conditions in the determination of uncertainties in pole extractions using Padé approximants
1
Grup de Física Teòrica, Departament de Física, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
2
Institut de Física d’Altes Energies (IFAE) and The Barcelona Institute of Science and Technology (BIST), Campus UAB, 08193, Bellaterra, Barcelona, Spain
a
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Received:
24
November
2025
Accepted:
19
January
2026
Published online:
29
January
2026
Abstract
In this letter, we discuss the determination of the 
resonance by analytic continuation through Padé approximants of the 
-scattering amplitude from the physical region to the pole in the complex energy plane. Using as input a class of admissible parameterizations of the scalar-isoscalar partial wave and imposing now the correct threshold behavior of the partial amplitude, we improve on the determinations of pole positions obtained in Caprini et al. (Phys Rev D 93(7):076004, 2016), thus empowering the Padé method as a simple and precise tool for extracting resonance poles from amplitudes.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
