MadGraph5_aMC@NLO

mg5decay useage with lots of decay chains

Asked by yd5

Hi experts,

I'm currently studying a process that has many decay chains, and I initially used the following syntax to simulate:

p p > A B, (A > C D, C > E F, D > G H), (B > I J, I > K L , J > M N)

Then I found that it was very time-consuming (as long as 15 hours!!!) to finish the simulation even though I only generated 1M events.

Then I heard that I could use "mg5decay" tool to speed up, the flow was something like:
1. generate 1M events by "p p > A B, (A > C D), (B > I J)" and stop here.
2. Then use mg5decay to add the left decay chain, i.e., C > E F, D > G H etc
3. As mg5decay will automatically run pythia and delphes, we are then ready to do analysis.

The idea is very clear, but I don't know how to get the second step done. If you could please help, I would really appreciate it.

Thanks a lot in advance,
Yong

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Revision history for this message
yd5 (fallive) said : 		#1

By the way, I do have done some research, but it seems that there is no information about mg5decay out there, even no related topics here. So I decide to post it.

But it could be wrong in the sense that mg5decay does not really speed up the simulation, which I am not sure. So please help.

Thanks!

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yd5 (fallive) said : 		#2

We figured it out and conclude that mg5decay can't do this actually.

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Olivier Mattelaer (olivier-mattelaer) said : 		#3

Hi,

I do not know any program called mg5decay. So I can not comment on that one. Are you sure about the name?
In those kind of package you have
MadSpin
DECAY (from MadGraph4, not supported anymore)

Cheers,

Olivier

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yd5 (fallive) said : 		#4

Hi Olivier,

We do have a folder inside MG with name mg5decay. Previously we though it would help solve our situation, but later we found it is madspin that does what we are seeking for. But thank you any way for the comment.

Best,
Yong

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Olivier Mattelaer (olivier-mattelaer) said : 		#5

Hi,

That's the directory for the automatic computation of the width sometimes dubbed "MadWidth".

Cheers,

Olivier