where ω ω = exp ⁡ ⁡ ( i 2 π π / 3 ) and ω ω ¯ ¯ = exp ⁡ ⁡ ( − − i 2 π π / 3 ) are the complex cube roots of unity. In the standard PDG convention, trimaximal mixing corresponds to: θ θ 12 = θ θ 23 = π π / 4 , θ θ 13 = sin − − 1 ⁡ ⁡ ( 1 / 3 ) and δ δ = π π / 2 . The Jarlskog C P -violating parameter J takes its extremal value | J | = 1 / ( 6 3 ) .