Trimaximal mixing[1] (also known as threefold maximal mixing[2]) refers to the highly symmetric, maximally CP-violating,
fermion mixing configuration, characterised by a unitary matrix (
) having all its elements equal in modulus (
) as may be written, e.g.: where
ω = exp ( i 2 π
ω ¯
= exp ( − i 2 π
are the complex cube roots of unity.
In the standard PDG[3] convention, trimaximal mixing corresponds to:
= π
sin
δ = π
[4] takes its extremal value
Originally proposed as a candidate lepton mixing matrix,[5][6] and actively studied[1][2][7][8] as such (and even as a candidate quark mixing matrix[9]), trimaximal mixing is now definitively ruled-out as a phenomenologically viable lepton mixing scheme by neutrino oscillation experiments, especially the Chooz reactor experiment,[10] in favour of the no longer tenable (related) tribimaximal mixing[11] scheme.