Broken S3L×S3R flavor symmetry and leptonic CP violationSupported by NNSFC (11325525), National Recruitment Program for Young Professionals and CAS Center for Excellence in Particle Physics (CCEPP)

Si, Zong-guo (School of Physics, Shandong University, Jinan, Shandong 250100, China) ; Yang, Xing-hua (School of Physics, Shandong University, Jinan, Shandong 250100, China) ; Zhou, Shun (Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China) (School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China) (Center for High Energy Physics, Peking University, Beijing 100871, China)

24 October 2017

Abstract: In the framework of the canonical seesaw model, we present a simple but viable scenario to explicitly break an S3L×S3R flavor symmetry in the leptonic sector. It turns out that the leptonic flavor mixing matrix is completely determined by the mass ratios of the charged leptons (i.e., me/mμ and mμ/mτ) and those of light neutrinos (i.e., m1/m2 and m2/m3). The latest global-fit results of the three neutrino mixing angles {θ12, θ13, θ23} and two neutrino mass-squared differences at the 3σ level are used to constrain the parameter space of {m1/m2,m2/m3}. The predictions for the mass spectrum and flavor mixing are highlighted: (1) the neutrino mass spectrum shows a hierarchical pattern and a normal ordering, e.g., m1≈2.2 meV, m2≈8.8 meV and m3≈52.7 meV; (2) only the first octant of θ23 is allowed, namely, 41.8°≲θ23≲43.3°; (3) the Dirac CP-violating phase δ≈−22° deviates significantly from the maximal value −90°. All these predictions are ready to be tested in ongoing and forthcoming neutrino oscillation experiments. Moreover, we demonstrate that the cosmological matter-antimatter asymmetry can be explained via resonant leptogenesis, including the individual lepton-flavor effects. In our scenario, leptonic CP violation at low- and high-energy scales is closely connected.

Published in: Chinese Phys. C 41 (2017) 113105
Published by: Institute of Physics Publishing/Chinese Academy of Sciences
DOI: 10.1088/1674-1137/41/11/113105
arXiv: 1706.03991
License: CC-BY-3.0

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