Z_2 Symmetry Prediction for the Leptonic Dirac CP Phase

Shao-Feng Ge; Duane A. Dicus; Wayne W. Repko

doi:10.1016/j.physletb.2011.06.096

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arXiv · 1104.0602

Z_2 Symmetry Prediction for the Leptonic Dirac CP Phase

Shao-Feng Ge·Duane A. Dicus·Wayne W. Repko

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Abstract

Model-independent consequences of applying a generalized hidden horizontal Z_2 symmetry to the neutrino mass matrix are explored. The Dirac CP phase delta_D can be expressed in terms of the three mixing angles as 4 c_a s_a c_s s_s s_x cos delta_D = (s^2_s - c^2_s s^2_x) (c^2_a - s^2_a) where the s_i, c_i are sines and cosines of the atmospheric, solar, and reactor angles. This relation is independent of neutrino masses and whether neutrinos are Dirac- or Majorana-type. Given the present constraints on the angles, delta_D is constrained to be almost maximal, a result which can be explored in experiments such as NOvA and T2K. The Majorana CP phases do not receive any constraint and are thus model-dependent. Also a distribution of theta_x with a lower limit is obtained without specifying delta_D.

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Shao-Feng Ge, Duane A. Dicus, Wayne W. Repko. 2011-04-04. Z_2 Symmetry Prediction for the Leptonic Dirac CP Phase. https://doi.org/10.1016/j.physletb.2011.06.096

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