Model of the Neutrino Mass Matrix With delta = -pi/2 and theta(23) = pi/4

作者：He, Xiao Gang^*

来源：Chinese Journal of Physics, 2015, 53(5): 100202.

DOI：10.6122/CJP.20150910B

Experimental data have provided stringent constraints on the neutrino mixing parameters. In the standard parameterization the mixing angle theta(23) is close to pi/4. There is also evidence which shows that the CP violating phase is close to -pi/2. We study the neutrino mass matrix reconstructed using this information and find several interesting properties. We show that a theoretical model based on the A(4) symmetry naturally predicts delta = -pi/2 and theta(23) = pi/4 when the Yukawa couplings and scalar vacuum expectation values are real, reaching mu - tau exchange and CP conjugate symmetry limit. In this case CP violation solely comes from the complex group theoretical Clebsh-Gordan coefficients. The model also predicts vertical bar V-e2 vertical bar = 1/root 3 consistent with the data. With complex Yukawa couplings the values for delta and theta(23) can significantly deviate away from the symmetry values -pi/2 and pi/4, respectively. But vertical bar V-e2 vertical bar = 1/root 3 is not altered. This matrix is an excellent lowest order approximation for theoretical model buildings of the neutrino mass matrix.

• 出版日期2015-10
• 单位上海交通大学; 清华大学