Texture dynamics including potential sterile neutrino

Abstract

A unified form of mass matrix proposed previously for all fundamental fermions is extended to include the sterile neutrino $\nu_s$, presumed to mix mainly with $\nu_e$, while $\nu_\tau$ mixes strongly with $\nu_\mu$ (and both $\nu_\mu$ and $\nu_\tau$ weakly with $\nu_e$ and $\nu_s$). It turns out that the former mixing can be responsible for oscillations of solar neutrinos, while the latter for those of atmospheric neutrinos. It is mentioned in a footnote that $\nu_s$ is one of two sterile neutrinos, possible from a viewpoint of an algebraic construction. The charged-lepton factor $U^{(e)}$ in the leptonic four-dimensional CKM matrix $V=U^{(\nu) \dagger}U^{(e)}$ is determined through the small deviation of our previous prediction $m_\tau=1776.80$ MeV (valid at the level of $ U^{(e)} = {\bf 1}$) from the experimental value $m_\tau=1777.00^{+0.30}_{-0.27}$ MeV. Then, it gives corrections to the four-dimensional mixing of $\nu_e$, $\nu_\mu$, $\nu_\tau$, $\nu_s$ leading, in particular, to small $\nu_e\to\nu_\mu$, $\nu_e\to \nu_\tau$ and $\nu_\mu\to\nu_s$ oscillations (absent at the level of $U^{(e)}= 1$). However, the LSND estimates of $\bar{\nu}_\mu \to \bar{\nu}_e$ and $\nu_\mu\to\nu_e$ oscillations are too large to be explained by these corrections, though in the case of $\nu_\mu \to\nu_e$ they seem to be at the edge of such possible explanation.