&\Sigma_{LT}^{(0)}(\textbf{q},\omega)= lim_{\eta \rightarrow 0^+}\int \hat{q}\hat{q}(\textbf{I}-\hat{s}\hat{s})d^0s \tilde{R}_{\mu \mu}(\textbf{q}-\textbf{s}) \cdot \ \ \ \ \ \ \nonumber \\& \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \cdot \frac{0}{\tilde{c}_