assigned particle id in off-shell processes

Hi,

Concerning the mapping of Feynman diagram, you can check this thread:
https://answers.launchpad.net/mg5amcnlo/+question/187387

To understand when a particle is written in the lhe file, you can check the following FAQ:
https://answers.launchpad.net/mg5amcnlo/+faq/2173
The reason, is that such information should only be used by the parton-shower to know how they have to shower such event.

Cheers,

Olivier

On 7 Oct 2017, at 00:13, Alexander <<email address hidden><mailto:<email address hidden>>> wrote:

New question #659084 on MadGraph5_aMC@NLO:
https://answers.launchpad.net/mg5amcnlo/+question/659084

Dear all,

I am trying to produce gridpacks for a simplified DM model with a Z' mediator and an additional dark higgs scalar [1,2].
In the example setup I am posting the lhe [3], the Z' has a mass of 1.2 TeV (pdgid 55), the dark Higgs of 90 GeV (pdgid 54) and the DM particle of 200 GeV (pdgid 52). I am generating events doing p p > DM DM Hs, (Hs > b b~) [4].
As you can see from the LHE, in each event there is an entry around 1.2 TeV but the id is 54 for the first event and 25 for the second and third. Is this behaviour expected? Is it because the event history has no physical meaning and the Zp is off-shell before radiating off the dark Higgs? What puzzles me about this, I saw for example in G5.13 of the P1_uux_dmdmhs_hs_bbx sub-process that "lconfig=igraphs(1)" in addmothers is either 6,9,12 or 15 [5]. What does that mean and how can I understand the mapping of the diagrams to 5?

Cheers and thanks for any additional info,

Alexander.

[1] http://www.desy.de/~agrohsje/hidden/understanding_id/ZpHiggs/
[2] https://arxiv.org/pdf/1606.07609.pdf
[3] http://www.desy.de/~agrohsje/hidden/understanding_id/example.lhe
[4] http://www.desy.de/~agrohsje/hidden/understanding_id/proc_card.dat
[5] www.desy.de/~agrohsje/hidden/understanding_id/P1_uux_dmdmhs_hs_bbx.ps

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Dear Olivier,

sorry for coming back to this tread.
1.) In fact, my question was triggered by my understanding of bwcutoff. Because in the short LHE example, second event in [3], I see e.g. a particle with ID 25, i.e. the SM Higgs boson, that has 1.2 TeV mass (the actual mass of the Z' in that model).

2.) I saw the answer from John before, but the mapping between the diagrams of the subprocess and the integration channels is very simple in my case:

  DATA (CONFSUB(I,1),I=1,1)/1/
      DATA (CONFSUB(I,2),I=1,1)/2/
      DATA (CONFSUB(I,3),I=1,1)/3/
      DATA (CONFSUB(I,4),I=1,1)/4/
      DATA (CONFSUB(I,5),I=1,1)/5/
      DATA (CONFSUB(I,6),I=1,1)/6/
      DATA (CONFSUB(I,7),I=1,1)/7/
      DATA (CONFSUB(I,8),I=1,1)/8/
      DATA (CONFSUB(I,9),I=1,1)/9/
      DATA (CONFSUB(I,10),I=1,1)/10/
      DATA (CONFSUB(I,11),I=1,1)/11/
      DATA (CONFSUB(I,12),I=1,1)/12/
      DATA (CONFSUB(I,13),I=1,1)/13/
      DATA (CONFSUB(I,14),I=1,1)/14/
      DATA (CONFSUB(I,15),I=1,1)/15/
      DATA (CONFSUB(I,16),I=1,1)/16/
      DATA (CONFSUB(I,17),I=1,1)/17/

so I still don't understand why e.g. G5.13 (what is the meaning of the second number 13 ?) of the P1_uux_dmdmhs_hs_bbx sub-process, "lconfig=igraphs(1)" (l 111 in addmothers.f) is either 6,9,12 or 15 [5]. What does that mean?

Cheers and thanks for any further help, Alexander.

Hi,

The .X for the channel indicates that you can not have all particle onshell at the same time in the decay-chain.
We then split the channel in smaller channel (indicated by the .X) such that for each of them it is decided which one is on-shell and which one is off shell. The X encodes some ternary value which encodes the exact choice of onshell/offshell particles. This obviously depend of the channel selected (so 4.13 is not the same particle onshell/offshell than 5.13) the easiest way to know what choice was made is to look at the log of the associated channel, at the beginning of the log, this information is printed.

Cheers,

Olivier

Dear Olivier,

thanks a lot!

In run1_app.log, I find :
Running Configuration Number: 5
 Using dconfig= 13
 BW Setting 1 1 1 0

Does that mean that the integration channel 5 [5], i.e. the diagram in which the Zp radiates of a dark Higgs, is calculated by using diagram 13 whith the Higgs getting a mass of 1.2 TeV?
What is the meaning in the BW Setting row above?

Cheers, Alexander.

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