set max_npoint_for_channel 0 Overflow error for certain masses

I can certainly send the model UFO if required

Hi,

You should remove the dynamical_scale_choice for the computation.
The code can not compute the running of alpha_s at such low scale.

Cheers,

Olivier

> On 11 Jun 2020, at 18:15, Isaac Sanderson <email address hidden> wrote:
>
> New question #691267 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/691267
>
> Hi,
>
> I am trying to run a simple dark photon model, where I generate ~xd ~xd~ > dvb dvb (where ~xd is the fermionic dark matter, and dvb is the dark vector boson), however for dvb masses between 300-400 MeV it gives an error trying to generate the events:
>
> set max_npoint_for_channel 0
> Traceback (most recent call last):
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 1514, in onecmd
> return self.onecmd_orig(line, **opt)
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 1463, in onecmd_orig
> return func(arg, **opt)
> File "/opt/madgraph/madgraph/interface/madevent_interface.py", line 2461, in do_generate_events
> switch_mode = self.ask_run_configuration(mode, args)
> File "/opt/madgraph/madgraph/interface/madevent_interface.py", line 6172, in ask_run_configuration
> self.ask_edit_cards(cards, plot=False, first_cmd=first_cmd)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 966, in ask_edit_cards
> banner=banner)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 1038, in ask_edit_card_static
> cards=cards, mode=mode, **opt)
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 1113, in ask
> question_instance.postcmd(answer, line)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 5948, in postcmd
> ending_question = cmd.OneLinePathCompletion.postcmd(self,stop,line)
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 2346, in postcmd
> return self.reask(reprint_opt)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 5940, in reask
> cmd.OneLinePathCompletion.reask(self,*args, **opt)
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 2168, in reask
> self.postcmd(stop, answer)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 5956, in postcmd
> self.do_update('dependent', timer=20)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 6002, in do_update
> self.do_compute_widths('')
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 6372, in do_compute_widths
> out = self.mother_interface.do_compute_widths(line)
> File "/opt/madgraph/madgraph/interface/common_run_interface.py", line 2288, in do_compute_widths
> out = cmd.exec_cmd(line, model=opts['model'])
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 1543, in exec_cmd
> stop = Cmd.onecmd_orig(current_interface, line, **opt)
> File "/opt/madgraph/madgraph/interface/extended_cmd.py", line 1463, in onecmd_orig
> return func(arg, **opt)
> File "/opt/madgraph/madgraph/interface/master_interface.py", line 343, in do_compute_widths
> return self.cmd.do_compute_widths(self, *args, **opts)
> File "/opt/madgraph/madgraph/interface/madgraph_interface.py", line 8111, in do_compute_widths
> data = model.set_parameters_and_couplings(opts['path'], scale= mass)
> File "/opt/madgraph/models/model_reader.py", line 178, in set_parameters_and_couplings
> value = runner(scale)
> File "/opt/madgraph/models/model_reader.py", line 316, in __call__
> return self.newton1(t, self.amc, 3)
> File "/opt/madgraph/models/model_reader.py", line 365, in newton1
> FP=1/(AS**2*(1+c1*AS))
> OverflowError: (34, 'Numerical result out of range')
>
> ************************************************************************
> ************************************************************************
>
> I am using the default run card, with run file
>
> import model ./SMDP_UFO/
> set automatic_html_opening False
> generate ~xd ~xd~ > dvb dvb
> output DPdvb
> launch DPdvb
> set nevents 10000
> set gsm 1.00000E-05
> set adm 2.40000E+00
> set mdvb 3.00000E-01
> set mxd 1.00000E+05
> set ebeam1 1.00001E+05
> set ebeam2 1.00001E+05
> set WDVB Auto
>
> ****************************
>
> gsm is the mixing parameter between the dvb and the SM photon, and adm is the dark fine structure constant. No idea why it's upset, even when changing the model to only couple dvb to electrons, I still get the error. Any insight would be cherished.
>
>
>
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks for such a quick response Oliver,

I have changed the run card parameters as such:

  True = fixed_ren_scale ! if .true. use fixed ren scale
  True = fixed_fac_scale ! if .true. use fixed fac scale
  91.188 = scale ! fixed ren scale
  91.188 = dsqrt_q2fact1 ! fixed fact scale for pdf1
  91.188 = dsqrt_q2fact2 ! fixed fact scale for pdf2
  -1 = dynamical_scale_choice ! Choose one of the preselected dynamical choices
  1.0 = scalefact ! scale factor for event-by-event scales

To try and fix the scale, however I am still getting the same error. Sorry for my ignorance but is this what you meant by remove the dynamical_scale_choice?

Thanks

Ah the issue is in the computation of the width of the WDVB.
I have to look for a work around (like settinng as to zero for such low scale)
For the moment, you will need to compute the width manually then

Cheers,

Olivier

> On 12 Jun 2020, at 01:15, Isaac Sanderson <email address hidden> wrote:
>
> Question #691267 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/691267
>
> Status: Answered => Open
>
> Isaac Sanderson is still having a problem:
> Thanks for such a quick response Oliver,
>
> I have changed the run card parameters as such:
>
> True = fixed_ren_scale ! if .true. use fixed ren scale
> True = fixed_fac_scale ! if .true. use fixed fac scale
> 91.188 = scale ! fixed ren scale
> 91.188 = dsqrt_q2fact1 ! fixed fact scale for pdf1
> 91.188 = dsqrt_q2fact2 ! fixed fact scale for pdf2
> -1 = dynamical_scale_choice ! Choose one of the preselected dynamical choices
> 1.0 = scalefact ! scale factor for event-by-event scales
>
> To try and fix the scale, however I am still getting the same error.
> Sorry for my ignorance but is this what you meant by remove the
> dynamical_scale_choice?
>
> Thanks
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Unfortunately the dvb decaying is a key component to what I am trying to achieve haha... I am passing the events onto pythia to decay, and then getting spectra. The decay to SM fermions is a rather trivial width to calculate, but for when the pions start coming into play in this 0.3-0.4 GeV part I am not so sure.

Thank you for your assistance

Hi,

> but for when the pions start coming into play in this 0.3-0.4
> GeV part I am not so sure.

The auto width, will not include any effect of non perturbative QCD anyway (see https://arxiv.org/pdf/1402.1178.pdf <https://arxiv.org/pdf/1402.1178.pdf>)

Cheers,

Olivier

> On 12 Jun 2020, at 08:41, Isaac Sanderson <email address hidden> wrote:
>
> Question #691267 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/691267
>
> Status: Answered => Open
>
> Isaac Sanderson is still having a problem:
> Unfortunately the dvb decaying is a key component to what I am trying to
> achieve haha... I am passing the events onto pythia to decay, and then
> getting spectra. The decay to SM fermions is a rather trivial width to
> calculate, but for when the pions start coming into play in this 0.3-0.4
> GeV part I am not so sure.
>
> Thank you for your assistance
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Ah yes thank you Olivier. I will compute it manually for now,

Cheers