Why is the $3\times 3$ neutrino mixing matrix almost unitary in realistic seesaw models?

dc.creatorXing, Zhi-zhong
dc.creatorZhou, Shun
dc.date2005-12-22
dc.date.accessioned2026-07-07T06:54:20Z
dc.date.available2026-07-07T06:54:20Z
dc.descriptionA simple extension of the standard model is to introduce $n$ heavy right-handed Majorana neutrinos and preserve its $\rm SU(2)^{}_L \times U(1)^{}_Y$ gauge symmetry. Diagonalizing the $(3+n) \times (3+n)$ neutrino mass matrix, we obtain an exact analytical expression for the effective mass matrix of $ν^{}_e$, $ν^{}_μ$ and $ν^{}_τ$. It turns out that the $3\times 3$ neutrino mixing matrix $V$, which appears in the leptonic charged-current weak interactions, must not be exactly unitary. The unitarity violation of $V$ is negligibly tiny, however, if the canonical seesaw mechanism works to reproduce the correct mass scale of light Majorana neutrinos. A similar conclusion can be drawn in the realistic Type-II seesaw models.
dc.descriptionRevTex 8 pages, no figures
dc.identifierhttps://arxiv.org/abs/hep-ph/0512290
dc.identifierhttp://arxiv.org/abs/hep-ph/0512290
dc.identifierHigh Energy Phys.Nucl.Phys. 30 (2006) 828-832
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/105898
dc.subjectHigh Energy Physics - Phenomenology
dc.titleWhy is the $3\times 3$ neutrino mixing matrix almost unitary in realistic seesaw models?
dc.typetext

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