What doesμ−τsymmetry imply about neutrino mixings?

2006/01/31 by Kenichi Fuki, Masaki Yasue, Masaki Yasuè · 4 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Neutrino #Neutrino Physics Research #Order (exchange) #Particle physics #Particle physics theoretical and experimental studies #Physics #hep-ph

paper · pdf · doi:10.1103/physrevd.73.055014

published as Phys.Rev. D73 (2006) 055014 · 10 pages, title slightly modified, comments added in the introdction, typos corrected, references updated, version to appear in Physical Reviews D

arxiv created 2006/03/15 · openalex publication_date 2006/03/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

The requirement of the \ensuremathμ\ensuremath-\ensuremathτ symmetry in the neutrino sector that yields the maximal atmospheric neutrino mixing is shown to yield either sin\ensuremathθ₁₃=0 (referred to as C1)) or sin\ensuremathθ₁₂=0 (referred to as C2)), where \ensuremathθ₁₂₍₁₃₎ stands for the solar (reactor) neutrino mixing angle. We study general properties possessed by approximately \ensuremathμ\ensuremath-\ensuremathτ symmetric textures. It is argued that the tiny \ensuremathμ\ensuremath-\ensuremathτ symmetry breaking generally leads to cos2\ensuremathθ₂₃\ensuremath∼sin\ensuremathθ₁₃ for C1) and cos2\ensuremathθ₂₃\ensuremath∼\ensuremathΔm_\ensuremath\bigodot²/\ensuremathΔm_atm²(\ensuremath≡R) for C2), which indicates that the smallness of cos2\ensuremathθ₂₃ is a good measure of the \ensuremathμ\ensuremath-\ensuremathτ symmetry breaking, where \ensuremathΔm_atm² (\ensuremathΔm_\ensuremath\bigodot²) stands for the square mass difference of atmospheric (solar) neutrinos. We further find that the relation R\ensuremath∼sin²\ensuremathθ₁₃ arises from contributions of O(sin²\ensuremathθ₁₃) in the estimation of the neutrino masses (m_1,2,3) for C1), and that possible forms of textures are strongly restricted to realize sin²2\ensuremathθ₁₂=O(1) for C2). To satisfy R\ensuremath∼sin²\ensuremathθ₁₃ for C1), neutrinos exhibit the inverted mass hierarchy, or the quasi degenerate mass pattern with |m_1,2,3|\ensuremath∼O(√\ensuremathΔm_atm²), and, to realize sin²2\ensuremathθ₁₂=O(1) for C2), there should be an additional small parameter \ensuremathη whose size is comparable to that of the \ensuremathμ\ensuremath-\ensuremathτ symmetry breaking parameter \ensuremathε, giving tan2\ensuremathθ₁₂\ensuremath∼\ensuremathε/\ensuremathη with \ensuremathη\ensuremath∼\ensuremathε to be compatible with the observed large mixing.

Citations

• Determination of neutrino mass texture for maximal CP violation
• Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in the Sudbury Neutrino Observatory
• Leptogenesis in seesaw models with a two-fold-degenerate neutrino Dirac mass matrix
• Neutrino mass matrix with approximate flavor symmetry
• Neutrino 2-3 symmetry and inverted hierarchy
• Remarks on the Unified Model of Elementary Particles
• Softly broken lepton numbers and maximal neutrino mixing
• Leptogenesis andμ−τsymmetry
• Measurement of the Rate ofνe+d→p+p+e−Interactions Produced byB<mml:mprescripts/>8Solar Neutrinos at the Sudbury Neutrino Observatory
• Universal texture of quark and lepton mass matrices and a discrete symmetryZ3
• CP-Violation in the Renormalizable Theory of Weak Interaction
• Measurements of the Solar Neutrino Flux from Super-Kamiokande's First 300 Days
• 2-3 symmetry: Flavor changingb,τdecays, and neutrino mixing

Cited by

• Neutrino mass, dark matter and anomalous magnetic moment of muon in a U 1 L μ − L τ U(1)_L__μ-L__τ model
• Baryon asymmetry from leptogenesis with four zero neutrino Yukawa textures
• Can the four-zero-texture mass matrix model reproduce the observed quark and lepton mixing angles andCP-violating phases?
• Common origin ofμ−τandCPbreaking in the neutrino seesaw, baryon asymmetry, and hidden flavor symmetry
• Neutrino mixing and leptogenesis inμ−τsymmetry