MadGraph5_aMC@NLO

I saw in DJR plots, the plot goes to zero before log(DJR) = 3.0 value. But in my DJR1 plot for e- e+ > t t~ + jets , the plot continues after 3.0. Is it correct?

Asked by Reza Jafari

Dear experts,

I am working on a project on top quark at the electron-positron colliders, e-e+ -> ttbar+(jet) where I have to perform merging.
I performed the MLM matching and for sanity check I prepared the DJR plots. I would be very much grateful if you help me with the following explanation and give advice.

- I plotted the DJR1 figure for e- e+ > t t~ + jets process. In our DJR1 plot (0 jet sample -> 1 jet sample), the range of DJR parameter is not like the others. In my DJR2, DJR3 (and also DJR1 in other processes that I saw in some presentations), plots go to zero before log(DJR) = 3.0. But in my DJR1 plot, it continues after 3.0 value. I am not sure whether this plot is correct or not?
If log(DJR1) can take values larger than 3.0, how can we change the range of the parameter in the plot?

- In order to compare the results of matching (just for 0-jet and 1-jet samples), I chose different values for xqcut (in Madgraph run card) and qCut (in pythia card). I prepared DJR plot for below values:
xqcut = 10 , qCut = 10
xqcut = 20 , qCut = 20
xqcut = 20 , qCut = 30
I don't have any idea which values for xqcut and qCut parameters are the best? And which plot is suitable for an acceptable matching? I think all plots are smooth with little differences.

I would greatly appreciate any assistance or advice you could offer me.

Thank you very much for your time.
Best regards,

Reza

PS.
Some more details of what we have done are as follows.

MadGraph:
C.M. energy = 3 TeV
generate e- e+ > t t~ @0
add process e- e+ > t t~ j @1
add process e- e+ > t t~ j j @2
add process e- e+ > t t~ j j j @3
ickkw = 1, xqcut = 10 or 20 or ... , qCut = 10 or 20 or 30, ...

MadAnalysis:
bin/ma5 -H
ma5> install fastjet
ma5> import <path-to-the-event-file>/pythia_events.hep.gz as ttjets
ma5> set main.merging.check = true
ma5> set main.merging.njets = 3 (for our purpose = 1)
ma5> submit output

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Can you put the plot online?
(If you want to attach them here, you first have to click on "create bug report" (present above the position where you can answer).

Cheers,

Olivier

PS: Answering by email will not keep the attacment (the platform trash them automatically)

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Reza Jafari (reza13) said : 		#2

Dear Olivier,

Thanks for your reply. I attached the plots with below names and explanations:

10_10.png : xqcut = 10 , qCut = 10
20_20.png : xqcut = 20 , qCut = 20
20_30.png : xqcut = 20 , qCut = 30

merging_plots.pdf :
In our DJR2, DJR3 (and also DJR1 in other processes as same as you presented in your slides) plots go to zero before log(DJR) = 3. But in our DJR1 plot, it continues after 3 value. I am not sure whether this plot is correct or not?

- My goal is to generate tt + ttj process with MLM merging. I just want to use a reliable matching with correct xqcut and Qcut parameters.

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Reza Jafari (reza13) said : 		#3

Link for other persons who want to see the attachment later:

https://bugs.launchpad.net/mg5amcnlo/+bug/1865848

Regards

Reza

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Launchpad Janitor (janitor) said : 		#4

This question was expired because it remained in the 'Open' state without activity for the last 15 days.