标题： 手征对称性和核子的矢量奇异性形式因子 显示英文标题

标题： Chiral Symmetry and the Nucleon's Vector Strangeness Form Factors

摘要： 从手征对称性的角度研究了核子的奇异数矢量流形式因子。有人认为手征微扰理论无法对奇异数半径和磁矩作出预测。要得出明确的预测，需要引入额外的、依赖于模型的假设，这些假设超出了手征微扰理论的框架。综述了各种此类模型预测，并评估了每种预测的可信度。最有可能的预测出现在一个模型中，在该模型中未知的手征反项被识别为$t$-通道矢量介子交换振幅。对应的平均平方狄拉克奇异数半径预测值为$\langle r_s^2\rangle = 0.24$fm$^2$，这一数值将在即将到来的基于半轻子确定核子奇异数形式因子的实验中被观测到。 显示英文摘要

摘要： The nucleon's strange-quark vector current form factors are studied from the perspective of chiral symmetry. It is argued that chiral perturbation theory cannot yield a prediction for the strangeness radius and magnetic moment. Arrival at definite predictions requires the introduction of additional, model-dependent assumptions which go beyond the framework of chiral perturbation theory. A variety of such model predictions is surveyed, and the credibility of each is evaluated. The most plausible prediction appears in a model where the unknown chiral counterterms are identified with $t$-channel vector meson exchange amplitudes. The corresponding prediction for the mean square Dirac strangeness radius is $\langle r_s^2\rangle = 0.24$ fm$^2$, which would be observable in up-coming semileptonic determinations of the nucleon's strangeness form factors.