标题： 介子在对称核物质中的色散关系 显示英文标题

标题： Dispersion relations of mesons in symmetric nuclear matter

摘要： 我们计算了相对论性、密集性、高温性、对称核物质中$\sigma$、$\omega$、$\pi$、$\rho$、$\delta$、$\eta$和$a_1$介子的色散关系和传播子。 除了通常的$\sigma-\omega$系统混合外，我们还得到了$\delta$与纵向$\rho$模式的混合，以及横向$\rho$与横向$a_1$模式的混合。 最后，$a_1$极化方向上的转移动量分量以类似于 Migdal 接触相互作用的方式修改了介质中的介子传播子，但符号相反。 通过一个接触项消除了虚假的介子凝聚以及来自$a_1$介子的额外贡献。 我们比较了两种实现接触项减法的方法。 显示英文摘要

摘要： We calculate dispersion relations and propagators for the $\sigma$, $\omega$, $\pi$, $\rho$, $\delta$, $\eta$ and $a_1$ mesons in relativistic, dense, hot, symmetric nuclear matter. In addition to the usual mixing of the $\sigma-\omega$ system, we obtain mixing of the $\delta$ with the longitudinal $\rho$ mode and of the tranverse $\rho$ with the transverse $a_1$ mode. Finally, the component of the $a_1$ polarization along the transferred momentum modifies the in-medium pion propagator in a way similar to the Migdal contact interaction, but with the opposite sign. The spurious pion condensate as well as the additional contribution from the $a_1$ meson are removed by a contact term. We compare two ways of implementing contact term subtraction.