The baryon form factor of charged pions arises since isospin symmetry is broken. We obtain estimates for this basic property in two phenomenological ways: from simple constituent quark models with unequal up and down quark masses, and from fitting to $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ data. All our methods yield a positive ${\pi }^{+}$ baryon mean square radius of ${(0.03-0.04\text{fm})}^2$. Hence, a picture emerges where the outer region has a net baryon, and the inner region a net antibaryon density, both compensating each other such that the total baryon number is zero. For ${\pi }^{-}$ the effect is opposite.

中文翻译：

---

π介子的重子含量

由于同位旋对称性被破坏，带电介子的重子形状因子出现了。我们通过两种现象学方式获得对这个基本性质的估计：从具有不等夸克质量的简单成分夸克模型，以及从拟合到${\mathrm{电子}}^{+}{\mathrm{电子}}^{-}\to {\pi }^{+}{\pi }^{-}$数据。我们所有的方法都产生了积极的结果${\pi }^{+}$ 重子均方半径 ${(0.03-0.04\text{调频})}^2$. 因此，出现了一幅图，其中外部区域具有净重子，内部区域具有净反重子密度，两者相互补偿，使得总重子数为零。为了${\pi }^{-}$ 效果相反。