MadGraph5_aMC@NLO

madspin final states with at least condition

Asked by Thibaud Vantalon

Hi,

I am doing an analysis and I am using MadSpin in order to decay my final states (w+ w+ w- w-). My problem
is that I want to have at least 2 same sign final state leptons, either positive or negative.

My question is the following. What is the better way to implement the condition "at least 2 same sign lepton" in MadSpin?
The "better" solution we found is:

-to decay "w+ > all all" and "w- > all all", remove the unwanted event and re-weight.

Thanks for your time.

Thibaud

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
Olivier Mattelaer Edit question
Solved by:
Thibaud Vantalon
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Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#1

This solution is fine but rather inefficient.

I would rather split my file in two (according to poison random variable if needed)
and then run two times MadSpin
once with
w- > l- vl~ (you need to redefine l- if you want to include tau inside)
w+ > j j
and the second time with
w- > j j
w+ > l+ vl

In order to run MS in standalone, you have an interface for that:
./MadSpin/madspin.
(the only difference compare to the madspin_card is that you first have to import your event file with the import command

Cheers,

Olivier

Revision history for this message
Thibaud Vantalon (thibaud-vantalon) said : 		#2

Thanks, That an interesting solution but sadly only partial. With this solution, I am missing the decay with more than 2 same sign leptons, like 2 same signs and one of opposite sign.

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#3

Indeed I didn't think of that point,
The solution is then to split the file in three and add this third decay scenario.
w- > l- vl~
w+ > l+ vl

Otherwise hack the code to hardcode this condition at the moment of choosing the decay.
If you think that this is worthed, I can give you some help in the implementation.

Cheers,

Olivier

Revision history for this message
Thibaud Vantalon (thibaud-vantalon) said : 		#4

OK,

Thank you very much.

For now I will use the first solution.