The Majorana neutrinos complex (MNC) is a dipole of matter and antimatter, and it forms a string with the electron (R-electron = MNC + electron). Per your fuzzy definition it could be a polariton because one has a dipole and a strong coupling with an electric field. MNC have electronuclear gravity and will form clusters ranging from a few eV to 100 of MeV. It is likely, that such clusters do not contain electrons. Some have called such cluster string vortex solitons.
The neutrino theories of cold fusion come from the Russian researchers, primarily from Parkhomov. I consider these hand waving theories as contrary to current science understanding.
Neutrinos are used in cold fusion theories because research in neutrinos are so obscure, difficult and hard to generate.
In this video, the baseline in the current history, research, and theory about the neutrino is painlessly presented.
Furthermore, the Majorana neutrino will be disproven if the sterile neutrino is detected.
This new article below describes a new experiment that may confirm a long-standing anomaly that may point to a fourth flavor of neutrino which would undercut the Majorana neutrino theory.