On effective Chern-Simons Term induced by a Local CPT-Violating Coupling using ${\gamma }_5$ in Dimensional Regularization

Ruggero Ferrari, Mario Raciti

We resume a long-standing, yet not forgotten, debate on whether a Chern-Simons birefringence can be generated by a local term $b_{\mu }\bar{\psi }{\gamma }^{\mu }{\gamma }_5\psi$ in the Lagrangian (where $b_{\mu }$ are c…