MadGraph5_aMC@NLO

No integration channels found for contribution

Asked by Antonio Sandroni

Hi, im generating mu+ mu- > z z z [LOonly]
I would like to know what [LOonly] really means.
When I launch it, it fails with the following error:
"WARNING program /*/SubProcesses/P0_mupmum_zzz/ajob1 1 all 0 0 launch ends with non zero status: 1. Stop all computation".
I have set some cuts on the final bosons, the folowing that work in another process pp>zzz
pt(Z)>1 Tev abs(eta(Z))<2.5 m(Z,Z)>1Tev R(Z,Z)>0.5

For the previous process I needed pdf setting lpp1=lpp2=1 but know i think I need to put lpp1=lpp2=0 because I have muons.
I think the problem is also in the choice of the dynamical_scale_choice that I havent fully understand even reading setscales.f; what does change between different values?
Thanks
Antonio

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
Last reply:
Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

The [LOonly] flag is usefull to run LO code within the framework of MCatNLO code, the main reason of that flag is for merging various multiplicity some at NLO and some at LO.

Otherwise, they are much less optimization and feature supported in that mode, so in general it is wiser to not use that flag.

> For the previous process I needed pdf setting lpp1=lpp2=1 but know i think I need to put lpp1=lpp2=0 because I have muons.
lpp=1 means proton collider, lpp=0 means no pdf.

> I think the problem is also in the choice of the dynamical_scale_choice that I havent fully understand even reading setscales.f; what does change between different values?

This is controlling the running of the strong coupling, since your process is a pure EW process, the most efficient way to run is to set the computation at a fixed scale (to avoid that the code computes a new value of the strong coupling even if this is not needed)

Cheers,

Olivier

Revision history for this message
Antonio Sandroni (antoniosandroni) said : 		#2

Ok, thank you.
but I dont' know how to evaluate the best fixed_renorm scale and fixed_fac scale according my initial states and parameters of energy of the process.
Could you help me?
Antonio

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

Should not have any impact,

Olivier

Can you help with this problem?

Provide an answer of your own, or ask Antonio Sandroni for more information if necessary.

To post a message you must log in.