Fant\^omas 无约束：基于 B\'ezier 参数化的全局 QCD 拟合
摘要
Fant\^omas 是一个用于探索 parton 分布函数（PDF）及其他相关子函数在量子色力学（QCD）中参数化依赖性的 C++ 工具包。Fant\^omas facilitates the generation of adaptable polynomial parametrizations for PDFs, called metamorphs, to find best-fit PDF solutions and quantify the epistemic uncertainty associated with the parametrizations during their fitting. The method employs B\'ezier curves as universal approximators for a variety of PDF shapes. Integrated into the xFitter framework for the global QCD analysis, Fant\^omas provides a foundation for general models of PDFs, while reducing the computational time compared to the approaches utilizing traditional polynomial parametrizations as well as providing an interpretable alternative to neural-network-based models. This paper outlines the structure and practical usage of the Fant\^omas toolkit, including its inputs, outputs, and implementation within xFitter. It also provides a practical example of using Fant\^omas for uncertainty quantification as well as the combination of PDF fits into a single ensemble.
引用
@article{arxiv.2507.22969,
title = {Fant\^omas Unconfined: global QCD fits with B\'ezier parameterizations},
author = {Lucas Kotz and Aurore Courtoy and T. J. Hobbs and Pavel Nadolsky and Fredrick Olness and Maximiliano Ponce-Chavez and Varada Purohit},
journal= {arXiv preprint arXiv:2507.22969},
year = {2025}
}
备注
33 pages, technical release of the Fant\^omas code: https://gitlab.com/cteq-tea/public/fantomas4qcd