Axial gravity, massless fermions and trace anomalies

Understand

This article deals with two main topics.

• One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity.
• The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly.
• The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach.