Nambu-Goldstone Bosons in CP Violating theory with Majorana Masses
  We derive some properties of the Nambu-Goldstone boson coupling in theories that have CP violation and Majorana masses. We show explicitly that its diagonal coupling to a Majorana fermion is pseudoscalar not scalar. This clarifies some confusion in the literature. Some potentially useful off-diagonal properties are also derived. We also show, in the process, that the Goldstone theorem often produces interesting and nontrivial identities in matrix theory which may be hard to prove otherwise. 
Darwin Chang, Wai-Yee Keung, and Chen-Pin Yeh