标题： 胶子极化在 e^+e^- -> t \bar t G 的研究：极角依赖性和束流极化效应 显示英文标题

标题： Gluon Polarization in e^+e^- -> t \bar t G: Polar Angle Dependence and Beam Polarization Effects

摘要： 我们计算在湮灭过程$e^+e^-\to q \bar q G$中与重夸克一起产生的胶子的线性偏振和圆偏振。 线性偏振是在强子事件平面以及胶子-束平面中计算的。 我们的讨论中包含了束偏振和偏振取向效应。 对于下一代直线对撞机（NLC）典型顶夸克对产生能量，胶子在强子事件平面中的线性偏振在其大部分能量谱范围内接近软胶子值的100%。 在胶子-束平面中的线性偏振通常较小，但趋向于胶子谱的硬端。 线性偏振对束偏振以及胶子的极化取向的依赖性较小。 圆偏振在胶子最大能量时最大，并对纵向束偏振有很强的依赖性。 因此，可以通过调节束的纵向偏振来调节胶子的圆偏振。 将重夸克的结果与无质量夸克情况下的相应结果进行了比较。 显示英文摘要

摘要： We calculate the linear and circular polarization of gluons produced in conjunction with massive quarks in the annihilation process $e^+e^-\to q \bar q G$. The linear polarization is calculated in the hadron event plane as well as in the gluon-beam plane. Beam polarization and polar orientation effects are included in our discussion. For typical top pair production energies at the Next-Linear-Collider (NLC) the degree of linear polarization in the hadron event plane remains close to its soft gluon value of 100% over most of the energy spectrum of the gluon. The linear polarization in the gluon-beam plane is generally smaller but peaks toward the hard end of the gluon spectrum. The dependence of the linear polarization on beam polarization and on the polar orientation of the gluon is small. The circular polarization is largest for maximal gluon energies and shows a strong dependence on the longitudinal beam polarization. The longitudinal polarization of the beam may therefore be used to tune the circular polarization of the gluon. The massive quark results are compared with the corresponding results for the massless quark case.