Scholarlink

<p>The strength of the interaction of three pions and a photon, <i>F</i><sub>3<i>π</i></sub> is predicted by the axial anomaly in terms of the pion decay constant, a relation that is frequently used to constrain low-energy radiative processes involving pions, but only tested experimentally at the 10% level. Here, we present a new avenue to test this prediction, via a fit of a dispersive description of the <i>γ</i><sup>∗</sup> → 3<i>π</i> amplitude to data for <i>e</i><sup>+</sup><i>e</i><sup>−</sup> → 3<i>π</i>. From the global fit to SND, CMD-2, and BaBar data we obtain <i>F</i><sub>3<i>π</i></sub> = 33.1(1.7) GeV<sup>−3</sup>, in agreement with the chiral prediction at the level of 5%. We also consider dispersive fits to the recent data by Belle II, in which case we observe tensions with the dispersive constraints, the width parameters of <i>ω</i> and <i>ϕ</i>, and the chiral anomaly.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Extracting the chiral anomaly from e+e− → 3π

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年7月8日

查看全文
  • Martin Hoferichter,
  • Bai-Long Hoid,
  • Bastian Kubis

摘要

The strength of the interaction of three pions and a photon, F3π is predicted by the axial anomaly in terms of the pion decay constant, a relation that is frequently used to constrain low-energy radiative processes involving pions, but only tested experimentally at the 10% level. Here, we present a new avenue to test this prediction, via a fit of a dispersive description of the γ∗ → 3π amplitude to data for e+e− → 3π. From the global fit to SND, CMD-2, and BaBar data we obtain F3π = 33.1(1.7) GeV−3, in agreement with the chiral prediction at the level of 5%. We also consider dispersive fits to the recent data by Belle II, in which case we observe tensions with the dispersive constraints, the width parameters of ω and ϕ, and the chiral anomaly.