Implication of a vanishing element in the3+1scenario

Abstract

In this paper we study the phenomenological implications of the one-zero textures of low energy neutrino mass matrices in the presence of a sterile neutrino. We consider the $3+1$ scheme and use the results from a global fit for short baseline neutrino oscillation data, which provides the bounds on the three additional mixing angles. We find that the mass matrix elements ${m}_{\ensuremath{\alpha}\ensuremath{\beta}}$ ($\ensuremath{\alpha}$, $\ensuremath{\beta}=e$, $\ensuremath{\mu}$, $\ensuremath{\tau}$) involving only the active states can assume vanishing values in the allowed parameter space for all of the mass spectrum. Among the mass matrix elements connecting the active and sterile states, ${m}_{es}$ and ${m}_{\ensuremath{\mu}s}$ can become small only for the quasidegenerate neutrinos. The element ${m}_{\ensuremath{\tau}s}$, on the other hand, can vanish even for lower values of masses since the 3--4 mixing angle only has an upper bound from current data. The mass matrix element (${m}_{ss}$) involving only the sterile state stays $\ensuremath{\sim}\mathcal{O}(1)\text{ }\text{ }\mathrm{eV}$ in the whole parameter region. We study the possible correlations between the sterile mixing angles and the Majorana phases to give a zero element in the mass matrix.