Matter effects on Majorana neutrino phases
  We consider the effect of ambient matter on the Majorana phase of neutrinos. We find that this can lead to an observable signal if a neutrino oscillation experiment could be performed where the source and the detector are at appropriately different matter densities. We illustrate the situation using a beta beam neutrino source as an example and show that a 5 sigma signal for the matter modification of the Majorana phase could be possible in a 5-year run. 
Amitava Raychaudhuri and Shashank M. Shalgar