Having trouble extracting result with only EFT vertices.

Asked by Ji-Chong Yang on 2020-10-29

Hello!

We need some help!
We are using MadGraph 2.7.2 with a UFO file containing some anormalus AAAZ, AAZZ, AZZZ, WWZZ vertices.

With FM2=8.0e-12, and all other EFT coefficients set to be 0
When we use p p > j j a z NP=1 QED=3 QCD=0 $$a z w+ w- to extract the VBS contribution induced by those anormaluse vertices, and followed by a madspin z > l+ l-, we find at 14TeV it was about 2.8fb(before madspin is about 40.7 fb)
Then we use p p > j j a l+ l- NP=1 QED=4 QCD=0 to include also tri-boson channels, we find the result is about 0.49fb, which is much smaller.
We think that it is not possible for the intereference to reduce the cross-section so much, so we run
generate p p > a > a z z
add process p p > a > a a z
add process p p > z > a z z
add process p p > z > a a z
add process p p > w+ > w+ a z
add process p p > w- > w- a z
Without madspin, the result is about 8fb so the tri-boson contribution to p p > j j l+ l- a should be smaller than 1fb, couldn't suppress the VBS so much (from 2.8fb to 0.49fb).

I think we must have made some mistakes, we need your help!

I have preserved all files to reproduce the problem if you need (I don't know how to attach them)

Thanks in advance!
Best regards!

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2020-10-30
Last query:
2020-10-30
Last reply:
2020-10-29

This question was reopened

What is your lepton cut?

Cheers,

Olivier

Ji-Chong Yang (nbalexis) said : #2

Dear Olivier!

We use the Standard Cuts as default settings (we only change the energy of beams in run_card and coefficients in param_card)
It is:

 10.0 = ptl ! minimum pt for the charged leptons
 -1.0 = ptlmax ! maximum pt for the charged leptons

 2.5 = etal ! max rap for the charged leptons
 0.0 = etalmin ! main rap for the charged leptons

 0.4 = drll ! min distance between leptons
 0.4 = drjl ! min distance between jet and lepton
 0.4 = dral ! min distance between gamma and lepton
 -1.0 = drllmax ! max distance between leptons
 -1.0 = drjlmax ! max distance between jet and lepton
 -1.0 = dralmax ! maxdistance between gamma and lepton

 0.0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
 -1.0 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair

 0.0 = mmnl ! min invariant mass for all letpons (l+- and vl)
 -1.0 = mmnlmax ! max invariant mass for all letpons (l+- and vl)

 0.0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
 -1.0 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)

 0.0 = xptl ! minimum pt for at least one charged lepton

 0.0 = ptl1min ! minimum pt for the leading lepton in pt
 0.0 = ptl2min ! minimum pt for the second lepton in pt
 -1.0 = ptl1max ! maximum pt for the leading lepton in pt
 -1.0 = ptl2max ! maximum pt for the second lepton in pt

Thank you for reply, we need your help!

Best Regards!

So this is your issue.
MadSpin does not apply any cut on the decaying particles.

Cheers,

Olivier

Ji-Chong Yang (nbalexis) said : #4

Dear Olivier!

We try to change drll from 0.4 to 0.001, and the cross-section increase to 2.6fb
That solved my problem!

Thank you very much!

Ji-Chong Yang (nbalexis) said : #5

Thanks Olivier Mattelaer, that solved my question.