Right unitarity triangles, stable CP-violating phases and approximate quark-lepton complementarity

Current experimental data indicate that two unitarity triangles of the CKM quark mixing matrix V are almost the right triangles with α≈90°. We highlight a very suggestive parametrization of V and show that its CP-violating phase ϕ is nearly equal to α (i.e., ϕ−α≈1.1°). Both ϕ and α are stable against the renormalizaton-group evolution from the electroweak scale MZ to a superhigh energy scale MX or vice versa, and thus it is impossible to obtain α=90° at MZ from ϕ=90° at MX. We conjecture that there might also exist a maximal CP-violating phase φ≈90° in the MNS lepton mixing matrix U. The approximate quark-lepton complementarity relations, which hold in the standard parametrizations of V and U, can also hold in our particular parametrizations of V and U simply due to the smallness of |Vub| and |Ve3|.