merging models

Asked by rohan on 2020-01-12

Hi,
I have two questions.
1. I have generated a UFO file with feynrules, consisting of higher dimensional operators of Standard Model particles. As I am importing this file in MG5_aMC_v2_6_6, I get the following warning:
MG5_aMC>import model higgs_dim6
INFO: failed to load model from pickle file. Try importing UFO from File
INFO: load particles
INFO: load vertices
CRITICAL: Model with non QCD emission of gluon (found 36 of those).
  This type of model is not fully supported within MG5aMC.
  Restriction on LO dynamical scale and MLM matching/merging can occur for some processes.
  Use such features with care.
INFO: Change particles name to pass to MG5 convention
Kept definitions of multiparticles l- / j / vl / l+ / p / vl~ unchanged
Defined multiparticle all = g a ve vm vt ve~ vm~ vt~ u c t d s b u~ c~ t~ d~ s~ b~ z w+ h w- e- mu- ta- e+ mu+ ta+
MG5_aMC>
Such a warning does not appear in previous versions of MG5_aMC. Could you explain why it appears and what it means? Is it fine to work with this ufo or do I need to look to rectify it?

2. I am trying to generate process g g > h z with my ufo file 'higgs_dim6' and also study its interference with sm at tree and one-loop level. So, for sm part I can get this process with loop_qcd_qed_sm:
>import model loop_qcd_qed_sm
>generate g g > h z [noborn=QED]
The above process occurs at tree and one-loop level. I wish to study it with my model. So, as I am adding model with 'add model ' command I get the following error:
MG5_aMC>import model loop_qcd_qed_sm
Switching to Feynman gauge because it is the only one supported by the model loop_qcd_qed_sm.
INFO: Restrict model loop_qcd_qed_sm with file models/loop_qcd_qed_sm/restrict_default.dat .
INFO: Run "set stdout_level DEBUG" before import for more information.
INFO: Change particles name to pass to MG5 convention
Pass the definition of 'j' and 'p' to 5 flavour scheme.
Kept definitions of multiparticles l- / vl / l+ / vl~ unchanged
Defined multiparticle all = g ghg ghg~ u c d s b u~ c~ d~ s~ b~ a gha gha~ ve vm vt e- mu- ta- ve~ vm~ vt~ e+ mu+ ta+ t t~ z w+ ghz ghwp ghwm h g0 g+ w- ghz~ ghwp~ ghwm~ g-
MG5_aMC>add model higgs_dim6_plugin
Command "add model higgs_dim6_plugin" interrupted with error:
USRMODERROR : Base Model doesn't follows UFO convention
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in 'MG5_debug'.
Please attach this file to your report.

Is it not possible to merge loop model with any other ufo model. Could you please suggest any solution?

Question information

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MadGraph5_aMC@NLO Edit question
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Last query:
2020-01-12
Last reply:
2020-01-12

Hi,

> Such a warning does not appear in previous versions of MG5_aMC. Could you explain why it appears and what it means? Is it fine to work with this ufo or do I need to look to rectify it?

It appears you have interaction of type g t t~ which are not of type QCD (and therefore likely not proportional to as). Some part of our code actually assumes that all gluon interactions are proportional to as. All the associated feature which can be problematic due to that will lead to a crash. In previous version, no warning was raised and the result could have been meaningless.

You can use the model without any issue, but you will not be able to do MLM type of generation or use our default dynamical scale,... (for some processes not for all).

> Is it not possible to merge loop model with any other ufo model. Could you please suggest any solution?

Merging model at NLO level is in principle forbidden. Adding a particle can modify loop and therefore you need to have the associated R2 pieces (and UV counter-term) to have a valid model.
Additionally the model loop_qcd_qed_sm is actually not a valid UFO model, This is a model that we created before the definiton of UFO model@NLO,...

Cheers,

Olivier

> On 12 Jan 2020, at 14:32, rohan <email address hidden> wrote:
>
> New question #687936 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/687936
>
> Hi,
> I have two questions.
> 1. I have generated a UFO file with feynrules, consisting of higher dimensional operators of Standard Model particles. As I am importing this file in MG5_aMC_v2_6_6, I get the following warning:
> MG5_aMC>import model higgs_dim6
> INFO: failed to load model from pickle file. Try importing UFO from File
> INFO: load particles
> INFO: load vertices
> CRITICAL: Model with non QCD emission of gluon (found 36 of those).
> This type of model is not fully supported within MG5aMC.
> Restriction on LO dynamical scale and MLM matching/merging can occur for some processes.
> Use such features with care.
> INFO: Change particles name to pass to MG5 convention
> Kept definitions of multiparticles l- / j / vl / l+ / p / vl~ unchanged
> Defined multiparticle all = g a ve vm vt ve~ vm~ vt~ u c t d s b u~ c~ t~ d~ s~ b~ z w+ h w- e- mu- ta- e+ mu+ ta+
> MG5_aMC>
> Such a warning does not appear in previous versions of MG5_aMC. Could you explain why it appears and what it means? Is it fine to work with this ufo or do I need to look to rectify it?
>
> 2. I am trying to generate process g g > h z with my ufo file 'higgs_dim6' and also study its interference with sm at tree and one-loop level. So, for sm part I can get this process with loop_qcd_qed_sm:
>> import model loop_qcd_qed_sm
>> generate g g > h z [noborn=QED]
> The above process occurs at tree and one-loop level. I wish to study it with my model. So, as I am adding model with 'add model ' command I get the following error:
> MG5_aMC>import model loop_qcd_qed_sm
> Switching to Feynman gauge because it is the only one supported by the model loop_qcd_qed_sm.
> INFO: Restrict model loop_qcd_qed_sm with file models/loop_qcd_qed_sm/restrict_default.dat .
> INFO: Run "set stdout_level DEBUG" before import for more information.
> INFO: Change particles name to pass to MG5 convention
> Pass the definition of 'j' and 'p' to 5 flavour scheme.
> Kept definitions of multiparticles l- / vl / l+ / vl~ unchanged
> Defined multiparticle all = g ghg ghg~ u c d s b u~ c~ d~ s~ b~ a gha gha~ ve vm vt e- mu- ta- ve~ vm~ vt~ e+ mu+ ta+ t t~ z w+ ghz ghwp ghwm h g0 g+ w- ghz~ ghwp~ ghwm~ g-
> MG5_aMC>add model higgs_dim6_plugin
> Command "add model higgs_dim6_plugin" interrupted with error:
> USRMODERROR : Base Model doesn't follows UFO convention
> Please report this bug on https://bugs.launchpad.net/mg5amcnlo
> More information is found in 'MG5_debug'.
> Please attach this file to your report.
>
> Is it not possible to merge loop model with any other ufo model. Could you please suggest any solution?
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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