Mismatch in rotation matrix convention leading to sign flips in trilinear couplings

[lisabiermann]

We currently use numerical methods to determine the eigensystem of the rotation matrices. This can lead to a mismatch with the desired rotation matrix parametrization in terms of angles. This mismatch then translates to false sign flips in the derivation of the trilinear couplings in the mass basis calculated by the executable TripleHiggsCouplingsNLO.

As all calculations related to phase transitions are done in the interaction basis, not the mass basis, this possible mismatch in the rotation matrix convention does not play a role for the results of the other executables.