KeyError ZERO when generating events

[Ekaterina]

Hello dear experts!

I am having a problem generating events in MadGraph.
 In the LanHEP package, I created a new model. In this model, a doubly charged particle X decays into two positrons and a gamma.

This is what I have in LanHEP:

model DMsimplescalar/1.
scalar x/X : ('X', mass MX1=1000, pdg 9000008).
spinor 'e-'/'e+' : ('Electron', pdg 11 ).
vector A/A : ('Photon',gauge).
parameter a1=1,b1=1,EE = 0.31333 : 'Electromagnetic coupling constant (<->1/128)'.

lterm X*anti(cc('e-'))*(a1+b1*gamma5)*'e+' + AddHermConj.
lterm -EE*A*x*deriv*X+ AddHermConj.
lterm -EE*'e-'*gamma*'e+'*A.

Next, I got the file in UFO format.
 In MadGraph, I import my model and generated events.

MG5_aMC>import model
MG5_aMC> generate x > e+ e+ a
MG5_aMC> output
MG5_aMC> launch

 Further after the launch command, I get the following message

Command "generate_events run_01" interrupted with error:
KeyError : 'ZERO'
More information is found in 'ME5_debug'.

Ca i send you the ME5_debug file?
What could be the mistake here?

[Olivier Mattelaer (olivier-mattelaer)]

Hi,

So the issue is that some width are set to the parameter "ZERO"
but such parameter is not defined.

you/they need to add the following in the parameters.py file

# This is a default parameter object representing 0.
ZERO = Parameter(name = 'ZERO',
                 nature = 'internal',
                 type = 'real',
                 value = '0.0',
                 texname = '0')

Cheers,

Olivier

> On 13 Oct 2019, at 10:42, Ekaterina <email address hidden> wrote:
>
> ** Attachment added: "ME5_debug"
> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.launchpad.net%2Fmg5amcnlo%2F%2Bbug%2F1847897%2F%2Battachment%2F5296791%2F%2Bfiles%2FME5_debug&amp;data=02%7C01%7C%7C237c7d7a259a43573b3908d74fba6ac2%7C7ab090d4fa2e4ecfbc7c4127b4d582ec%7C0%7C0%7C637065534984113590&amp;sdata=etJ%2BT7IBBXT6COn97HXXeTg6UjaOn3O5bootnFtzRsI%3D&amp;reserved=0
>
> ** Summary changed:
>
> - KeyError ZERO when geb=nerating events
> + KeyError ZERO when generating events
>
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>
> Title:
> KeyError ZERO when generating events
>
> Status in MadGraph5_aMC@NLO:
> New
>
> Bug description:
> Hello dear experts!
>
> I am having a problem generating events in MadGraph.
> In the LanHEP package, I created a new model. In this model, a doubly charged particle X decays into two positrons and a gamma.
>
> This is what I have in LanHEP:
>
> model DMsimplescalar/1.
> scalar x/X : ('X', mass MX1=1000, pdg 9000008).
> spinor 'e-'/'e+' : ('Electron', pdg 11 ).
> vector A/A : ('Photon',gauge).
> parameter a1=1,b1=1,EE = 0.31333 : 'Electromagnetic coupling constant (<->1/128)'.
>
> lterm X*anti(cc('e-'))*(a1+b1*gamma5)*'e+' + AddHermConj.
> lterm -EE*A*x*deriv*X+ AddHermConj.
> lterm -EE*'e-'*gamma*'e+'*A.
>
> Next, I got the file in UFO format.
> In MadGraph, I import my model and generated events.
>
> MG5_aMC>import model
> MG5_aMC> generate x > e+ e+ a
> MG5_aMC> output
> MG5_aMC> launch
>
> Further after the launch command, I get the following message
>
> Command "generate_events run_01" interrupted with error:
> KeyError : 'ZERO'
> More information is found in 'ME5_debug'.
>
> Ca i send you the ME5_debug file?
> What could be the mistake here?
>
> To manage notifications about this bug go to:
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