标题： 标量形式因子的色散分析 显示英文标题

标题： Dispersive analysis of the scalar form factor of the nucleon

摘要： 基于最近提出的介子-核子散射的Roy-Steiner方程，我们推导出pi pi --> N-bar N和K-bar K --> N-bar N S波的耦合积分方程。这些方程的形式是一个两通道Muskhelishvili-Omnes问题，在存在有限匹配点的情况下讨论了其解。我们利用这些结果，完全包括K-bar K中间态，更新了核子标量形式因子的色散分析。特别是，我们确定了校正Delta_sigma=sigma(2M_pi^2)-sigma_{π N}，该校正用于从pi N散射中提取介子-核子sigma项，作为介子-核子亚阈参数和pi N耦合常数的函数。 显示英文摘要

摘要： Based on the recently proposed Roy-Steiner equations for pion-nucleon scattering, we derive a system of coupled integral equations for the pi pi --> N-bar N and K-bar K --> N-bar N S-waves. These equations take the form of a two-channel Muskhelishvili-Omnes problem, whose solution in the presence of a finite matching point is discussed. We use these results to update the dispersive analysis of the scalar form factor of the nucleon fully including K-bar K intermediate states. In particular, we determine the correction Delta_sigma=sigma(2M_pi^2)-sigma_{pi N}, which is needed for the extraction of the pion-nucleon sigma term from pi N scattering, as a function of pion-nucleon subthreshold parameters and the pi N coupling constant.