UFO Parameters mixed up with restriction card
Dear authors,
I have just stumbled upon something puzzling and I was wondering if you could give me any insight.
I have a UFO model that has different EFT couplings for leptons of different flavors. I am using it to generate
mu+ mu- > t t~ SMHLOOP=0 NPprop=0 NP=1 NP^2==1 NPcHl1^2==1
to get the pure interference term of the cHl1 operator. cHl1 is not flavor specific, individual flavors are specified in the param card: cHl122 enters muon couplings, cHl133 tau couplings and cHl111 electron ones.
If I do this "normally", ie. importing the model in madgraph, and modifying the param card when I launch the generation, everything is fine and I get interference for cHl122 but not for cHl133, as expected.
If I do this importing the model with a restriction card (restrict_massless, also attached) that sets all the lepton masses to zero, I get the opposite. ie zero for cHl122 and nonzero for cHl133.
which cannot be, as one can check that the UFO does not contain any muon vertex with cHl133 and vice versa.
This happens for a number of operators, for some reason all those containing leptons. Operators with quarks are all fine.
And it happens consistently every time I import the model and generate processes with it, so it's not completely random.
I should also say that it does not depend on the process nor on the fact that I am generating a pure interference term.
Any clue why this comes about?!
Thanks a lot!
Ilaria
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