Problem in neutralino decays to gravitino

Asked by Juhi Dutta on 2018-11-19

Dear experts,

I am using the goldstino-gravitino UFO from Feynrules in Madgraph5 to generate the following process:

generate p p > n1 x1+ ,n1 > z grv
add process p p > n1 x1+ @2
output check_n1cha1

I obtain the following results after parton level run.

Net cross-section = 0.000342 GeV
For p p > n1 x1+ ,n1 > z grv , cross-section = 5.961*10^-13 GeV
For p p > n1 x1+ @2, cross-section = 0.0003375

The decay width of the lightest neutralino n1 is 3.47181007E-13 and the branching fraction to z grv is 0.548. Hence I was expecting a final cross-section value for the process involving decay of the neutralino to be production cross-section X branching ratio.
Hence I expect a value of 0.0003375*0.548 = 0.00018495. However the result I obtain is 5.961*10^-13 GeV.

This huge suppression is occuring whenever the neutralino decays to the gravitino. Also, the neutralino width gets reset to 0.0 for consistency during the run. I do not encounter this for other processes where the decays to gravitino don't enter. Could you kindly let me know what I should do to resolve this matter?

With Best Regard

Juhi

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
2019-01-09
Last reply:
2019-01-22

Olivier Mattelaer suggests this article as an answer to your question:
FAQ #2442: “why production and decay cross-section didn't agree.”.

Did you read the above FAQ?

If this does not help you. Do not hesitate to re-open this question.

Cheers,

Olivier

Juhi Dutta (dutta-juhi91) said : #3

Hi,

Thank you for the above link. Sorry for the trouble but I realised that the default width for n1 was set to width.ZERO and not the external parameter in particles.py which led to the warning for the decay width being set to 0. This removes the warning for n1. but there is another warning for n2:

WARNING: For consistency, the width of particle 1000023 (n2) is changed to -9.643513e-11.
The mass of n2 is -916.0 GeV. Could you please suggest how to resolve this issue?

Best Regards,

Juhi

Did you use 2.6.4?

This should be solve in that version in principle.

Cheers,

Olivier

Juhi Dutta (dutta-juhi91) said : #5

Hi,

I was earlier using version 2.6.2. I checked using v2.6.4, here the following warnings were displayed:

WARNING: Particle 1000022 will use a fake width ( 0.0009153118 instead of 3.47181007e-13 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
WARNING: Particle 1000023 will use a fake width ( -0.000917832 instead of 9.643513e-11 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
WARNING: Particle 1000024 will use a fake width ( 0.000916197 instead of 7.102998e-13 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
WARNING: Particle 2000001 will use a fake width ( 0.003016558 instead of 0.0003925336 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
WARNING: Particle 2000002 will use a fake width ( 0.003018958 instead of 0.001528193 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
WARNING: Particle 2000004 will use a fake width ( 0.003018957 instead of 0.002737752 ).
Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
INFO: Update the dependent parameter of the param_card.dat
ERROR: The width of particle 1000022 is too small for an s-channel resonance (3.47181007e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
ERROR: The width of particle 1000023 is too small for an s-channel resonance (9.643513e-11). If you have this particle in an s-channel, this is likely to create numerical instabilities .
ERROR: The width of particle 1000024 is too small for an s-channel resonance (7.102998e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
Generating 10000 events with run name run_01
survey run_01
INFO: compile directory
ERROR: The width of particle 1000022 is too small for an s-channel resonance (3.47181007e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
ERROR: The width of particle 1000023 is too small for an s-channel resonance (9.643513e-11). If you have this particle in an s-channel, this is likely to create numerical instabilities .
ERROR: The width of particle 1000024 is too small for an s-channel resonance (7.102998e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .

 I could not find the small_width_treatment in the run card in order to force the exact decay width. Could you please let me know where I could edit this feature?

Best Regards,

Juhi

This is in the run_card.
The line is not display by default but you can add it yourself.

Due to the value of your width for your particles it is more than likely than the results produced by MG5aMC
are not accurate anymore for such small width (just due to numerical precision of the matrix element)

You can reduce the default value of small_width_treatment obviously but do not set it to zero (or lower than 1e-12).

Cheers,

Olivier

> On 21 Nov 2018, at 13:38, Juhi Dutta <email address hidden> wrote:
>
> Question #676252 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/676252
>
> Status: Answered => Open
>
> Juhi Dutta is still having a problem:
> Hi,
>
> I was earlier using version 2.6.2. I checked using v2.6.4, here the
> following warnings were displayed:
>
> WARNING: Particle 1000022 will use a fake width ( 0.0009153118 instead of 3.47181007e-13 ).
> Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
> WARNING: Particle 1000023 will use a fake width ( -0.000917832 instead of 9.643513e-11 ).
> Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
> WARNING: Particle 1000024 will use a fake width ( 0.000916197 instead of 7.102998e-13 ).
> Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
> WARNING: Particle 2000001 will use a fake width ( 0.003016558 instead of 0.0003925336 ).
> Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
> WARNING: Particle 2000002 will use a fake width ( 0.003018958 instead of 0.001528193 ).
> Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
> WARNING: Particle 2000004 will use a fake width ( 0.003018957 instead of 0.002737752 ).
> Cross-section will be rescaled according to NWA if needed.To force exact treatment reduce the value of 'small_width_treatment' parameter of the run_card
> INFO: Update the dependent parameter of the param_card.dat
> ERROR: The width of particle 1000022 is too small for an s-channel resonance (3.47181007e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> ERROR: The width of particle 1000023 is too small for an s-channel resonance (9.643513e-11). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> ERROR: The width of particle 1000024 is too small for an s-channel resonance (7.102998e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> Generating 10000 events with run name run_01
> survey run_01
> INFO: compile directory
> ERROR: The width of particle 1000022 is too small for an s-channel resonance (3.47181007e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> ERROR: The width of particle 1000023 is too small for an s-channel resonance (9.643513e-11). If you have this particle in an s-channel, this is likely to create numerical instabilities .
> ERROR: The width of particle 1000024 is too small for an s-channel resonance (7.102998e-13). If you have this particle in an s-channel, this is likely to create numerical instabilities .
>
> I could not find the small_width_treatment in the run card in order to force the exact decay width. Could you please let me know where I could edit this feature?
>
> Best Regards,
>
> Juhi
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Juhi Dutta (dutta-juhi91) said : #7

Dear Sir,

I added the term in the run card manually in the following way:

1e-12= small_width_treatment

but this returned a compilation error pointing out that 'small_width_treatment' is not defined. Could you please let me know where I should I add this parameter in the code?

Best Regards,

Juhi

Did you try in 2.6.2?
YOu need 2.6.4 for that one.

Cheers,

Olivier

Juhi Dutta (dutta-juhi91) said : #9

Hi,

I am using v2.6.4.

Regards,

Juhi

I do not reproduce such problem.
Can you give more information.
(model/param_card/run_card/...)

or at least the debug file created with the crash?

In my case i have use the "set" syntax (set small_width_treatment 1e-12) which add the following line in the run_card:
 1e-12 = small_width_treatment # generation where the width is below VALUE times mass will be replace by VALUE times \
mass for the computation. The cross-section will be corrected assuming NWA. Not used for loop-induced process

And then I have the code running as expected.

Cheers,

Olivier

Juhi Dutta (dutta-juhi91) said : #11

Hi,

The model is the goldstino-gravitino model provided in Feynrules . Here is the debug file:

#************************************************************
#* MadGraph5_aMC@NLO/MadEvent *
#* *
#* * * *
#* * * * * *
#* * * * * 5 * * * * *
#* * * * * *
#* * * *
#* *
#* *
#* VERSION 2.6.4 20xx-xx-xx *
#* *
#* The MadGraph5_aMC@NLO Development Team - Find us at *
#* https://server06.fynu.ucl.ac.be/projects/madgraph *
#* *
#************************************************************
#* *
#* Command File for MadEvent *
#* *
#* run as ./bin/madevent.py filename *
#* *
#************************************************************
generate_events
Traceback (most recent call last):
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/extended_cmd.py", line 1501, in onecmd
    return self.onecmd_orig(line, **opt)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/extended_cmd.py", line 1450, in onecmd_orig
    return func(arg, **opt)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/madevent_interface.py", line 2469, in do_generate_events
    self.run_generate_events(switch_mode, args)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/common_run_interface.py", line 6801, in new_fct
    original_fct(obj, *args, **opts)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/madevent_interface.py", line 2508, in run_generate_events
    postcmd=False)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/extended_cmd.py", line 1528, in exec_cmd
    stop = Cmd.onecmd_orig(current_interface, line, **opt)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/extended_cmd.py", line 1450, in onecmd_orig
    return func(arg, **opt)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/madevent_interface.py", line 3277, in do_survey
    self.configure_directory()
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/madevent_interface.py", line 5605, in configure_directory
    self.compile(arg=[name], cwd=os.path.join(self.me_dir, 'Source'))
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/extended_cmd.py", line 1592, in compile
    return misc.compile(nb_core=self.options['nb_core'], *args, **opts)
  File "/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/bin/internal/misc.py", line 527, in compile
    raise MadGraph5Error, error_text
MadGraph5Error: A compilation Error occurs when trying to compile /scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source.
The compilation fails with the following output message:
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o StringCast.o StringCast.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o ranmar.o ranmar.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o alfas_functions.o alfas_functions.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o transpole.o transpole.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o invarients.o invarients.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o hfill.o hfill.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o pawgraphs.o pawgraphs.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o ran1.o ran1.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o rw_events.o rw_events.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o rw_routines.o rw_routines.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o kin_functions.o kin_functions.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o open_file.o open_file.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o basecode.o basecode.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o setrun.o setrun.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o run_printout.o run_printout.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o dgauss.o dgauss.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o readgrid.o readgrid.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o getissud.o getissud.f
    cd DHELAS; make
    cd PDF; make
    cd MODEL; make
    cd CERNLIB; make
    cd BIAS/dummy; make
    make[1]: Entering directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/PDF'
    make[1]: warning: jobserver unavailable: using -j1. Add `+' to parent make rule.
    make[1]: Entering directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/DHELAS'
    make[1]: make[1]: Entering directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/CERNLIB'
    warning: jobserver unavailable: using -j1. Add `+' to parent make rule.make[1]:
    warning: jobserver unavailable: using -j1. Add `+' to parent make rule.
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o Ctq6Pdf.o Ctq6Pdf.f
    make[1]: Entering directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/MODEL'
    make[1]: warning: jobserver unavailable: using -j1. Add `+' to parent make rule.
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o aloha_functions.o aloha_functions.f
    make[1]: Entering directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/BIAS/dummy'
    make[1]: warning: jobserver unavailable: using -j1. Add `+' to parent make rule.
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o dummy.o dummy.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o abend.o abend.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o couplings.o couplings.f
    run_card.inc:369.27:
        Included at setrun.f:78:

          SMALL_WIDTH_PARAMETER = ' 1e-12 '
                               1
    Error: Symbol 'small_width_parameter' at (1) has no IMPLICIT type
    make: *** [setrun.o] Error 1
    make: *** Waiting for unfinished jobs....
    ar cru ../../../lib/libbias.a dummy.o
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o dlsqp2.o dlsqp2.f
    ranlib ../../../lib/libbias.a
    make[1]: Leaving directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/BIAS/dummy'
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o lenocc.o lenocc.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o mtlprt.o mtlprt.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o pdfwrap.o pdfwrap.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o mtlset.o mtlset.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o opendata.o opendata.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o radmul.o radmul.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o pdf.o pdf.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o PhotonFlux.o PhotonFlux.f
    ar cru ../../lib/libcernlib.a abend.o dlsqp2.o lenocc.o mtlprt.o mtlset.o radmul.o
    ranlib ../../lib/libcernlib.a
    make[1]: Leaving directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/CERNLIB'
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o pdg2pdf.o pdg2pdf.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o NNPDFDriver.o NNPDFDriver.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FFV3_0.o FFV3_0.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FFV2_0.o FFV2_0.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV6_1.o FRV6_1.f
    ar cru ../../lib/libpdf.a Ctq6Pdf.o pdfwrap.o opendata.o pdf.o PhotonFlux.o pdg2pdf.o NNPDFDriver.o
    ranlib ../../lib/libpdf.a
    make[1]: Leaving directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/PDF'
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV1_1.o FRV1_1.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV1C1_2.o FRV1C1_2.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV4_1.o FRV4_1.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FFS2_0.o FFS2_0.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV3_1.o FRV3_1.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o lha_read.o lha_read.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV3C1_2.o FRV3C1_2.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o printout.o printout.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FFS1_3.o FFS1_3.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV4C1_2.o FRV4C1_2.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FFS2C1_0.o FFS2C1_0.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FRV6C1_2.o FRV6C1_2.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o FFV2_3.o FFV2_3.f
    ar cru ../../lib/libdhelas.a aloha_functions.o FFV3_0.o FFV2_0.o FRV6_1.o FRV1_1.o FRV1C1_2.o FRV4_1.o FFS2_0.o FRV3_1.o FRV3C1_2.o FFS1_3.o FRV4C1_2.o FFS2C1_0.o FRV6C1_2.o FFV2_3.o
    ranlib ../../lib/libdhelas.a
    make[1]: Leaving directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/DHELAS'
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o rw_para.o rw_para.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o model_functions.o model_functions.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o couplings1.o couplings1.f
    gfortran -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o couplings2.o couplings2.f
    ar cru ../../lib/libmodel.a couplings.o lha_read.o printout.o rw_para.o model_functions.o couplings1.o couplings2.o
    ranlib ../../lib/libmodel.a
    make[1]: Leaving directory `/scratch/juhi/workspace1/MG5_aMC_v2_6_4/check_n1cha1/Source/MODEL'

Please try to fix this compilations issue and retry.
Help might be found at https://answers.launchpad.net/mg5amcnlo.
If you think that this is a bug, you can report this at https://bugs.launchpad.net/mg5amcnlo
                              Run Options
                              -----------
               stdout_level : None

                         MadEvent Options
                         ----------------
     automatic_html_opening : False (user set)
        notification_center : True
          cluster_temp_path : None
             cluster_memory : None
               cluster_size : 100
              cluster_queue : None
                    nb_core : 24 (user set)
               cluster_time : None
                   run_mode : 2

                      Configuration Options
                      ---------------------
                text_editor : None
         cluster_local_path : None
      cluster_status_update : (600, 30)
               pythia8_path : /scratch/juhi/workspace1/MG5_aMC_v2_6_4/HEPTools/pythia8 (user set)
                  hwpp_path : None (user set)
            pythia-pgs_path : None (user set)
                    td_path : None (user set)
               delphes_path : /scratch/juhi/workspace1/MG5_aMC_v2_6_4/Delphes (user set)
                thepeg_path : None (user set)
               cluster_type : condor
          madanalysis5_path : None (user set)
           cluster_nb_retry : 1
                 eps_viewer : None
                web_browser : None
               syscalc_path : None (user set)
           madanalysis_path : None (user set)
                     lhapdf : /scratch/juhi/workspace1/MG5_aMC_v2_6_4/HEPTools/lhapdf6/bin/lhapdf-config (user set)
              f2py_compiler : None
                 hepmc_path : None (user set)
         cluster_retry_wait : 300
           fortran_compiler : None
                auto_update : 7 (user set)
        exrootanalysis_path : None (user set)
                    timeout : 60
               cpp_compiler : None

Regards,

Juhi

Ok I got it,

you define in your run_card:
SMALL_WIDTH_PARAMETER
while it should be
SMALL_WIDTH_TREATMENT

Maybe you add both in the card?

Cheers,

Olivier

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