Comment 2 for bug 1468429

Dear Khaled,

The problem is that first you are suppose to use
cmath.exp and not exp
cmath.sqrt and not sqrt
in most of the case this should go trough since those will be handle by fortran anyway but not in this context.

However, you have a four fermion interaction with a fermion flow violation (with identical particle) which is one case that we can not handle.
In order to generate events for your theory you need to introduce fake scalar to split the 4 point interaction in a succession of three point interaction.

Cheers,

Olivier

On 24 Jun 2015, at 17:11, Khaled Teilab <email address hidden> wrote:

> Public bug reported:
>
> Hi,
> I try to include a form factor in a model having two scalar particles (sig, phi) and two fermions (f1 and f2).
> The lagrangian used in feynrules looks like:
> g_1 Inner[Dot,Inner[Dot,{f1bar,f2bar },sig IdentityMatrix[2]],{f1,f2 }] + I g_2 (phi(CC[f1bar].Ga[5].f1) + anti[phi](f1bar.Ga[5].CC[f1]))
>
> In the attachment you find four models:
> 1) Model1: Includes ALL vertices coming from the above Lagrangian WITHOUT form factor => WORKS
> 2) Model4: Includes ONLY vertices involving the sig particle WITH form factor => WORKS
> 3) Model2: Includes ALL vertices coming from the above Lagrangian WITH form factor on ALL vertices => FAILS to produce output folder
> 4) Model3: Includes ALL vertices coming from the above Lagrangian WITH form factor on ONLY vertices involving the sig particle => FAILS to poruce output folder
>
> The output looks like:
>
> INFO: initialize a new directory: model3test
> INFO: remove old information in model3test
> INFO: Organizing processes into subprocess groups
> INFO: Generating Helas calls for process: f1+ f1+ > f1+ f1+ WEIGHTED=2
> INFO: Processing color information for process: f1+ f1+ > f1+ f1+
> INFO: Creating files in directory P0_f1pf1p_f1pf1p
> INFO: Generating Feynman diagrams for Process: f1+ f1+ > f1+ f1+ WEIGHTED=2
> INFO: Finding symmetric diagrams for subprocess group f1pf1p_f1pf1p
> History written to /home/teilab/mg/model3test/Cards/proc_card_mg5.dat
> Generated helas calls for 1 subprocesses (3 diagrams) in 0.011 s
> Wrote files for 12 helas calls in 0.154 s
> Export UFO model to MG4 format
> CRITICAL: aS not define as external parameter adding it!
> WARNING: aEWM1 and Gf not define in MODEL. AQED will not be written correcty in LHE FILE
> ALOHA: aloha creates FFS2 routines
> Command "output model3test" interrupted with error:
> NameError : name 'exp' is not defined
> Please report this bug on https://bugs.launchpad.net/madgraph5
> More information is found in 'MG5_debug'.
> Please attach this file to your report.
>
> Could you please have a look at the attached models and tell me what the
> problem is? The debug file is also attached
>
> Thanks,
> Khaled
>
> ** Affects: mg5amcnlo
> Importance: Undecided
> Status: New
>
> ** Attachment added: "models and debug file"
> https://bugs.launchpad.net/bugs/1468429/+attachment/4420064/+files/spiegeltest.tar.gz
>
> --
> You received this bug notification because you are subscribed to
> MadGraph5_aMC@NLO.
> https://bugs.launchpad.net/bugs/1468429
>
> Title:
> Form factors with transposed spinors bug
>
> Status in MadGraph5_aMC@NLO Generator:
> New
>
> Bug description:
> Hi,
> I try to include a form factor in a model having two scalar particles (sig, phi) and two fermions (f1 and f2).
> The lagrangian used in feynrules looks like:
> g_1 Inner[Dot,Inner[Dot,{f1bar,f2bar },sig IdentityMatrix[2]],{f1,f2 }] + I g_2 (phi(CC[f1bar].Ga[5].f1) + anti[phi](f1bar.Ga[5].CC[f1]))
>
> In the attachment you find four models:
> 1) Model1: Includes ALL vertices coming from the above Lagrangian WITHOUT form factor => WORKS
> 2) Model4: Includes ONLY vertices involving the sig particle WITH form factor => WORKS
> 3) Model2: Includes ALL vertices coming from the above Lagrangian WITH form factor on ALL vertices => FAILS to produce output folder
> 4) Model3: Includes ALL vertices coming from the above Lagrangian WITH form factor on ONLY vertices involving the sig particle => FAILS to poruce output folder
>
> The output looks like:
>
> INFO: initialize a new directory: model3test
> INFO: remove old information in model3test
> INFO: Organizing processes into subprocess groups
> INFO: Generating Helas calls for process: f1+ f1+ > f1+ f1+ WEIGHTED=2
> INFO: Processing color information for process: f1+ f1+ > f1+ f1+
> INFO: Creating files in directory P0_f1pf1p_f1pf1p
> INFO: Generating Feynman diagrams for Process: f1+ f1+ > f1+ f1+ WEIGHTED=2
> INFO: Finding symmetric diagrams for subprocess group f1pf1p_f1pf1p
> History written to /home/teilab/mg/model3test/Cards/proc_card_mg5.dat
> Generated helas calls for 1 subprocesses (3 diagrams) in 0.011 s
> Wrote files for 12 helas calls in 0.154 s
> Export UFO model to MG4 format
> CRITICAL: aS not define as external parameter adding it!
> WARNING: aEWM1 and Gf not define in MODEL. AQED will not be written correcty in LHE FILE
> ALOHA: aloha creates FFS2 routines
> Command "output model3test" interrupted with error:
> NameError : name 'exp' is not defined
> Please report this bug on https://bugs.launchpad.net/madgraph5
> More information is found in 'MG5_debug'.
> Please attach this file to your report.
>
> Could you please have a look at the attached models and tell me what
> the problem is? The debug file is also attached
>
> Thanks,
> Khaled
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1468429/+subscriptions