Non-transversality of the gluon polarization tensor in a chromomagnetic   background
  We investigate the question about the transversality of the gluon polarization tensor in a homogeneous chromomagnetic background field. We re-derive the non transversality known from a pure one loop calculation using the Slavnov-Taylor identities. In addition we generalize the procedure to arbitrary gauge fixing parameter $\xi$ and calculate the $\xi$-dependent part of the polarization tensor. 
M. Bordag, J. Grebenyuk, V. Skalozub