paper

Non-vanishing and from a broken symmetry

arXiv:hep-ph/0408123 · doi:10.1016/j.nuclphysb.2005.01.049

Abstract

It is shown that the neutrino mass matrices in the flavour basis yielding a vanishing are characterized by invariance under a class of symmetries. A specific in this class also leads to a maximal atmospheric mixing angle . The breaking of that can be parameterized by two dimensionless quantities, $\e$ and $\e'$; the effects of $\e, \e' \neq 0$ are studied perturbatively and numerically. The induced value of $\ue3$ strongly depends on the neutrino mass hierarchy. We find that $\ue3$ is less than 0.07 for a normal mass hierarchy, even when $\e, \e' \sim 30 %$. For an inverted mass hierarchy $\ue3$ tends to be around 0.1 but can be as large as 0.17. In the case of quasi-degenerate neutrinos, $\ue3$ could be close to its experimental upper bound 0.2. In contrast, can always reach its experimental upper bound 0.28. We propose a specific model, based on electroweak radiative corrections in the MSSM, for $\e$ and $\e'$. In that model, both $\ue3$ and , could be close to their respective experimental upper bounds if neutrinos are quasi-degenerate.

28 pages, 12 figures, Some discussions are revised, references are corrected, Conclusions are unchanged

References in corpus (4)

Cited by in corpus (102)