A left-right SU(7) symmetric model with D-parity cosmic strings
  Cosmic strings with the property of D-parity symmetry are studied in this paper. They are of a Z-2 type of strings that could appear in the spontaneous breaking of SU(7) and would present extraordinary properties in a background of ordinary and mirror neutrinos. Through the special embedding of the left-right symmetry in SU(7), with a minimal content of Higgs fields, based on two singlets and two doublets, it is possible to assure the topological stability of this type of cosmic strings. In their presence we could have a neutral flavor changing interaction between ordinary and mirror neutrinos as well as the formation of superconducting currents in the form of zero modes of neutrino mirrors that would show interesting effects. 
Helder Chavez S. and J. A. Martins Simoes