FCNC z-prime may not be working well since MadGraph5_v1_4_3?
Since version 18.104.22.168 I observe that when introducing a new model (à la v4) with FCNC Z', it does not work well. For instance, when the coupling is set to zero, gives a non-sense cross section in tt~ production.
These are my files (only relevant lines showing):
zp zp V W zpm zpw S zp 2198
u t zp gzp QED
t u zp gzp QED
c UserMode couplings
That is for the model. Then, in the working directory:
import model_v4 zprime
generate p p > t t~ QED=2 @1
1 0.00000000e+00 # fr,
4000 = ebeam1 ! beam 1 energy in GeV
4000 = ebeam2 ! beam 2 energy in GeV
So well, the issue comes when I run ./bin/generate_
I am confused: if the coupling fr is set to 0, it should retrieve the SM cross section, right?
Thanks for your great software, and for your great availability here in launchpad,