Andrew, Bob A good paper on this subject (longitudinal waves) is “Unravelling the potentials puzzle and corresponding case for the scalar longitudinal electrodynamic wave” Donald Reed 2019 J. Phys.: Conf. Ser. 1251 012043
Reed does not make the scalar to neutrino connection, which seems to serve the same purposes, which is to explore the line between what is real and what seems real because it balances equations. The best thing one can say about QM is that it lends physical credulity to an imaginary world… but then again, what is real? From: Andrew Meulenberg …. At the short distance of deep-orbits from the nucleus, the neutrino (considered to be similar to photons) would be in the "longitudinal photon" mode
