CalcHEP

unmatching between graphical and batch session in calculating width

Asked by Joe

Dear Sir.
    I'm using calchep_3.8.10 to test a dark photon model, but when I try to calculate the decay rate of the process: Ap -> M m ("Ap" is dark photon, defined in the model), the graphical session and the batch session give different result: graphical session's result is 2.4e-11 GeV, while the batch session's result is 2.4e-12 GeV, 10 times smaller than the former. I have checked the "session.dat" file and confirm that all the physical parameters are the same. And the graphical session's result is supposed to be right.
    Interestingly, when I try to calculate the decay rate of process: Ap -> E e , it does run. The unmatching between graphical and batch session disappears. This problem confuses me a lot, can you tell me what may be the reason for this unmatching?

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Alexander Belyaev (alexander.belyaev) said : 		#1

Thanks for the reporting this problem.
Could you send me your model and the batch file.
I need to reproduce your problem first.
You can send files to <email address hidden>
Best
Alexander

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Alexander Belyaev (alexander.belyaev) said : 		#2

Do you need help?

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Joe (lzj777) said : 		#3

I have sent files to the mailbox above a few days ago, did you receive it?
Best

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Alexander Pukhov (pukhov) said : 		#4

I guess to pass files you have to use our personal e-mails.

For instance,  <email address hidden>

I guess your dark photon is presented in Feynman gauge ( label G in
Aux), but Goldstone fiels is absent ( look ar Z,tau,tau).

In such case result depends on gauge. More likely batch and GUI used
different default gauge.

For massless particle gauge dependence is absent and you get the same
results for electron.

I recommend you to check gauge dependence in GUI and after that remove
"G" label  in description of  dark photon.

Best

    Alexander Pukhov

On 7/19/21 5:01 PM, Joe wrote:
> Question #697745 on CalcHEP changed:
> https://answers.launchpad.net/calchep/+question/697745
>
> Joe posted a new comment:
> I have sent files to the mailbox above a few days ago, did you receive it?
> Best
>

Revision history for this message
Joe (lzj777) said : 		#5

Yes there is a label G in Aux for dark photon, but after I removed it, the problem still existed.

No matter I set "Gauge: Feynman" or "Gauge: unitary" in batch file, the outcome width is 2.371e-12 GeV.
No matter I turn on or turn off the "Force Unit.Gauge" in GUI, the outcome width is 2.431e-11 GeV.

I have forward the files mail to the mailbox above, could you please check it?

Thanks.

Revision history for this message
Alexander Pukhov (pukhov) said : 		#6

Without  usrFF.c I have the same result  both in batch and GUI. Do you
see the same?

Best

    Alexander Pukhov

On 7/20/21 4:01 PM, Joe wrote:
> Question #697745 on CalcHEP changed:
> https://answers.launchpad.net/calchep/+question/697745
>
> Status: Answered => Open
>
> Joe is still having a problem:
> Yes there is a label G in Aux for dark photon, but after I removed it,
> the problem still existed.
>
> No matter I set "Gauge: Feynman" or "Gauge: unitary" in batch file, the outcome width is 2.371e-12 GeV.
> No matter I turn on or turn off the "Force Unit.Gauge" in GUI, the outcome width is 2.431e-11 GeV.
>
> I have forward the files mail to the mailbox above, could you please
> check it?
>
> Thanks.
>

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