The model cannot handle loop processes.

Asked by Huchan Lee

Dear MG experts,

I am having trouble calculating the Drell-Yan process at NLO using a specific model. The model is a simple extension of type II 2HDM with one singlet flavon, which we generated through SARAH and SPheno. To calculate the Drell-Yan process at NLO, I utilized the UFO file generated by SARAH for the model, but encountered an error in the process:

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load MG5 configuration from input/mg5_configuration.txt
fastjet-config does not seem to correspond to a valid fastjet-config executable (v3+). We will use fjcore instead.
 Please set the 'fastjet'variable to the full (absolute) /PATH/TO/fastjet-config (including fastjet-config).
 MG5_aMC> set fastjet /PATH/TO/fastjet-config

set ninja to /home/leeh/MG5_aMC_v3_4_1/HEPTools/lib
set collier to /home/leeh/MG5_aMC_v3_4_1/HEPTools/lib
set lhapdf to /home/leeh/MG5_aMC_v3_4_1/HEPTools/LHAPDF-6.5.3/LHAPDF_install/bin/lhapdf-config
set lhapdf to /home/leeh/MG5_aMC_v3_4_1/HEPTools/LHAPDF-6.5.3/LHAPDF_install/bin/lhapdf-config
Using default text editor "vi". Set another one in ./input/mg5_configuration.txt
Using default eps viewer "evince". Set another one in ./input/mg5_configuration.txt
Using default web browser "firefox". Set another one in ./input/mg5_configuration.txt
Loading default model: sm
INFO: Restrict model sm with file models/sm/restrict_default.dat .
INFO: Run "set stdout_level DEBUG" before import for more information.
INFO: Change particles name to pass to MG5 convention
Defined multiparticle p = g u c d s u~ c~ d~ s~
Defined multiparticle j = g u c d s u~ c~ d~ s~
Defined multiparticle l+ = e+ mu+
Defined multiparticle l- = e- mu-
Defined multiparticle vl = ve vm vt
Defined multiparticle vl~ = ve~ vm~ vt~
Defined multiparticle all = g u c d s u~ c~ d~ s~ a ve vm vt e- mu- ve~ vm~ vt~ e+ mu+ t b t~ b~ z w+ h w- ta- ta+
MG5_aMC>import model THDM_Global_UFO/ -modelname
impossible to set default multiparticles vl~ because No particle ve~ in model
Kept definitions of multiparticles p / j / l+ / l- / vl unchanged
Removed obsolete multiparticles vl~ / all
Defined multiparticle all = g ah2 a nu1 nu2 nu3 d1 d2 d3 d4 d5 u1 u2 u3 u4 u5 d1bar d2bar d3bar d4bar d5bar u1bar u2bar u3bar u4bar u5bar h1 h2 h3 ah3 hm2c z wmc hm2 wm e1 e2 e3 e4 e5 nu4 nu5 nu6 nu7 e1bar e2bar e3bar e4bar e5bar
MG5_aMC>generate p p > e2 e2bar [noborn=QCD]
The current model THDM_Global_UFO does not allow to generate loop corrections of type ['QCD'].
Command "generate p p > e2 e2bar [noborn=QCD]" interrupted with error:
InvalidCmd : The model THDM_Global_UFO cannot handle loop processes

After some searches, I discovered that there are already some similar cases, and I believe this is a closely related one.

https://answers.launchpad.net/mg5amcnlo/+question/704535

Based on the response provided in the inquiry, it appears that rewriting the Lagrangian and parameters in FeynRules with the NLOCT package is necessary to calculate loop processes. However, I am wondering if the same approach can be applied to our UFO file or if there is a way to enable loop process calculations within SARAH for our specific UFO file.

Many thanks in advance
Huchan Lee

Question information

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

Hi,

I guess that this is a question for Sarah author.
I would be afraid to say that this is not possible while this is actually just me not aware enough in SARAH capabilities.

Cheers,

Olivier

Revision history for this message
Huchan Lee (huchanlee) said :
#2

Thanks Olivier Mattelaer, that solved my question.