Determination of neutrino mass texture for maximal CP violation

We show a general form of neutrino mass matrix (M), whose matrix elements are denoted by Mij(i,j=e,μ,τ) as flavor neutrino masses, that induces maximal CP violation as well as maximal atmospheric neutrino mixing. The masses of Mμμ, Mττ and Mμτ+σMee(σ=±1) turn out to be completely determined by Meμ and Meτ for given mixing angles. The appearance of CP violation is found to originate from the interference between the μ-τ symmetric part of M and its breaking part. If |Meμ|=|Meτ|, giving either Meμ=−σeiθMeτ or Meμ=−σeiθMeτ* with a phase parameter θ, is further imposed, we find that |Mμμ|=|Mττ| is also satisfied. These two constraints can be regarded as an extended version of the constraints in the μ-τ symmetric texture given by Meμ=−σMeτ and Mμμ=Mττ. Majorana CP violation becomes active if arg(Mμτ)≠arg(Meμ)+θ/2 for Meμ=−σeiθMeτ and if arg(Mμτ)≠θ/2 for Meμ=−σeiθMeτ*.