LC issue with loop-induced process
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
MadGraph5_aMC@NLO |
Confirmed
|
Undecided
|
Valentin Hirschi |
Bug Description
When generating an event with madgraph like this:
generate c~ g > H g c~ QED=1 [QCD]
launch
if I look into the LHE event card, I get events such as the following:
<event>
5 0 +4.0285366e-02 1.36540700e+02 7.54677100e-03 1.21806100e-01
-4 -1 0 0 0 501 +0.0000000000e+00 +0.0000000000e+00 +2.9419141131e+03 2.9419141131e+03 0.0000000000e+00 0.0000e+00 -1.0000e+00
21 -1 0 0 501 502 -0.0000000000e+00 -0.0000000000e+00 -2.1835375839e+01 2.1835375839e+01 0.0000000000e+00 0.0000e+00 -1.0000e+00
25 1 1 2 0 0 +4.5770992300e+01 +2.9989942130e+01 +2.0255992823e+02 2.4423330013e+02 1.2500000000e+02 0.0000e+00 0.0000e+00
21 1 1 2 501 501 -1.3125965953e+01 +2.3701158420e+01 +3.1121389496e+02 3.1239097987e+02 0.0000000000e+00 0.0000e+00 -1.0000e+00
-4 1 1 2 0 502 -3.2645026347e+01 -5.3691100550e+01 +2.4063049140e+03 2.4071252089e+03 0.0000000000e+00 0.0000e+00 -1.0000e+00
<mgrwt>
<rscale> 4 0.13654070E+
<asrwt>0</asrwt>
<pdfrwt beam="1"> 1 -4 0.45260186E+00 0.13654070E+
<pdfrwt beam="2"> 1 21 0.33592909E-02 0.13654070E+
<totfact> 0.87394861E+
</mgrwt>
</event>
where a gluon singlet state has been produced (with color tags 501 501). Is this expected behaviour? It seems when I try to subsequently shower the event with Pythia, it gives me the error 'unphysical color flow'
Changed in mg5amcnlo: | |
assignee: | Olivier Mattelaer (olivier-mattelaer) → Valentin Hirschi (valentin-hirschi) |
See the associate question for more details on this issue