Berry phase in neutrino oscillations
Journal
Physical Review D - Particles, Fields, Gravitation and Cosmology
Journal Volume
72
Journal Issue
5
Date Issued
2005
Author(s)
Abstract
We study the Berry phase in neutrino oscillations for both Dirac and Majorana neutrinos. In order to have a Berry phase, the neutrino oscillations must occur in a varying medium, the neutrino-background interactions must depend on at least two independent densities, and also there must be $CP$ violation. If the neutrino interactions with matter are mediated only by the standard model $W$ and $Z$ boson exchanges, these conditions imply that there must be at least three generations of neutrinos. The $CP$ violating Majorana phases do not play a role in generating a Berry phase. We show that a natural way to satisfy the conditions for the generation of a Berry phase is to have sterile neutrinos with active-sterile neutrino mixing, in which case at least two active and one sterile neutrinos are required. If there are additional new $CP$ violating flavor changing interactions, it is also possible to have a nonzero Berry phase with just two generations.
Type
journal article