{"paper":{"title":"New analysis for Nucleon Form Factors from GPDs","license":"http://creativecommons.org/licenses/by/4.0/","headline":"The AMA25 ansatz for generalized parton distributions yields lower reduced chi-squared fits and more stable extrapolations than the prior GSAMA24 model.","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Fatemeh Arbabifar, Nader Morshedian, Shahin Atashbar Tehrani","submitted_at":"2026-05-13T20:09:18Z","abstract_excerpt":"Generalized Parton Distributions (GPDs) provide a comprehensive framework for describing the three-dimensional structure of the nucleon. Extracting GPDs from experimental data requires flexible and physically motivated ansatz. In this study, we introduce a new ansatz, AMA25, designed to address the limitations of the previous model, GSAMA24 (Phys. Rev. C 111 (2025) 2, 025203). We conduct a fast and efficient comparison by fitting AMA25 models and other relevant data using the iMinuit optimization package within a Jupyter Notebook environment. The AMA25 ansatz demonstrates superior fit quality,"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The AMA25 ansatz demonstrates superior fit quality, achieving a reduced χ², while better satisfying theoretical constraints. Additionally, AMA25 exhibits enhanced stability when extrapolated to the exclusive region.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the new AMA25 functional form is sufficiently flexible and physically motivated to overcome the limitations of GSAMA24 without introducing new biases or overfitting when parameters are adjusted to the same data sets.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A new ansatz AMA25 for GPDs achieves lower reduced chi-squared fits to nucleon form factor data and better satisfies theoretical constraints than the prior GSAMA24 model.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"The AMA25 ansatz for generalized parton distributions yields lower reduced chi-squared fits and more stable extrapolations than the prior GSAMA24 model.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"dc61153d653bf4875c0a4c7865a1bc7980a0becbb13913ef109bd18c5020737f"},"source":{"id":"2605.14083","kind":"arxiv","version":1},"verdict":{"id":"c3e6f859-bdc0-48e9-97b1-fe417d7d3e6f","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T01:58:12.355429Z","strongest_claim":"The AMA25 ansatz demonstrates superior fit quality, achieving a reduced χ², while better satisfying theoretical constraints. Additionally, AMA25 exhibits enhanced stability when extrapolated to the exclusive region.","one_line_summary":"A new ansatz AMA25 for GPDs achieves lower reduced chi-squared fits to nucleon form factor data and better satisfies theoretical constraints than the prior GSAMA24 model.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the new AMA25 functional form is sufficiently flexible and physically motivated to overcome the limitations of GSAMA24 without introducing new biases or overfitting when parameters are adjusted to the same data sets.","pith_extraction_headline":"The AMA25 ansatz for generalized parton distributions yields lower reduced chi-squared fits and more stable extrapolations than the prior GSAMA24 model."},"references":{"count":51,"sample":[{"doi":"","year":1994,"title":"D. Muller, D. Robaschik, B. Geyer, F. M. Dittes and J. Horejsi, Fortsch. Phys.42, 101-141 (1994)","work_id":"61dce8da-f154-4ea3-ad78-ab04a271ac45","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1997,"title":"X. D. Ji, Phys. Rev. Lett.78, 610-613 (1997) Phys. Rev. Lett.78, 610-613 (1997)","work_id":"f655ea41-6b18-4d2d-a8d7-d577c84af9f4","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1997,"title":"A. V. Radyushkin, Phys. Rev. D56, 5524-5557 (1997)","work_id":"d38bafd2-76f2-44a6-81a2-306cbb6045c7","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"M. ˇCui´ c, G. Duplanˇ ci´ c, K. Kumeriˇ cki and K. Passek-K., JHEP12, 192 (2023). [erratum: JHEP02, 225 (2024)]","work_id":"1736777c-9ca8-4ffe-a881-204e70410da1","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1997,"title":"X. D. Ji, Phys. Rev. D55, 7114-7125 (1997) Phys. Rev. D55, 7114-7125 (1997)","work_id":"3f2cc8bd-ca19-4ce9-9f34-0e509b15a366","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":51,"snapshot_sha256":"7d27700b4abf3661fbfcf97ddf45b3b574875762f9fe188a6b0837be5bbbf013","internal_anchors":1},"formal_canon":{"evidence_count":2,"snapshot_sha256":"e0c8bf663c5f67780c06db578cd7cdbfefce088b5cc8378b19ce8915be35aacb"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}