标题： 临界维度下弦理论的Siegel-Zwiebach作用中基于有限场依赖BRST变换的小质量引力子传播子 显示英文标题

标题： Small mass graviton propagator via finite-field-dependent BRST transformations in the critical dimension Siegel-Zwiebach action from string theory

摘要： 我们讨论了在$D=26$中发散的无质量引力子传播子极限问题，并展示了如何通过在临界维度下通过对来自弦理论的不同规范固定的 Siegel-Zwiebach 生成泛函施加适当的有限场依赖 BRST（FFBRST）变换来严格处理这一问题。 可以从单位规范下的 Siegel-Zwiebach 规范不变拉格朗日中以特定情况得到质量 Fierz-Pauli 拉格朗日，然而它会遭受 van Dam-Veltman-Zakharov 不连续性，并且在无质量极限下传播子定义不良。 尽管如此，通过在更合适的广义 Lorenz 型规范下工作，包括横迹零情况，可以使得 Siegel-Zwiebach 拉格朗日在无质量极限下的引力子传播子变得有限。 明确计算了规范可达性和幂零 BRST 对称性。 我们写下了完整的对应生成泛函，包括鬼场部分，并构造了一个方便的 FFBRST 变换，连接了单位规范到一个新的双参数化规范固定类，其中包括横迹零情况。 考虑到费曼积分雅可比对应的改变，得到了一个有限的无质量连续极限传播子，并完全证明了其合理性。 显示英文摘要

摘要： We discuss the divergent graviton propagator massless limit problem in $D=26$ and show how it can be rigorously approached by interconnecting distinct gauge-fixed Siegel-Zwiebach generating functionals from string theory in the critical dimension through proper finite-field-dependent BRST (FFBRST) transformations. The massive Fierz-Pauli Lagrangian can be obtained from the gauge-invariant Siegel-Zwiebach one in the unitary gauge as a particular case, however suffering from the van Dam-Veltman-Zakharov discontinuity and possessing a ill-defined propagator in the massless limit. Nevertheless, alternatively working in a more suitable generalized Lorenz type gauge, including the transverse-traceless case, the graviton propagator for the Siegel-Zwiebach Lagrangian in the massless limit can be made finite. Gauge attainability and nilpotent BRST symmetries are explicitly worked out. We write down the complete corresponding generating functional, including the ghosts sector, and construct a convenient FFBRST transformation connecting the unitary gauge to a new bi-parametrized class of gauge-fixings containing the transverse traceless case. By taking into account the corresponding change in the Feynman integral Jacobian, a finite massless continuous limit propagator is achieved and fully justified.