ISR in madgraph

Hi,

"EVA" is when you consider "W/Z/photon" as part of the constituent of the electron.
In that case you need to have a process like
generate w+ w- > t t~
launch
set ebeam 1500.0
set lpp1 +3
set lpp2 -3
set pdlabel1 eva
set pdlabel2 eva

Which does not seem to be the approximation/scenario that you are looking for.

> By the way, in 2108.10261, the PDF isronlyll , cepc240ll, clic3000ll, fcce240ll, fcce365ll and ilc500ll are also recommended, are they also OK? Because when I try them, they give me zero result.

Yes, I would either not include any pdf, or include either isronlyll or clic3000ll
(the other one being fit for another center-of-mass collision.

Why do you get zero result?
In this patch (part of the future 3.3.2) I have made some fix but those should not have any impact on the cross-section (but if you configure your compiler with very secure flag)

https://bazaar.launchpad.net/~maddevelopers/mg5amcnlo/3.3.2/revision/976

Cheers,

Olivier

> On 22 Dec 2021, at 07:15, Rui Zhang <email address hidden> wrote:
>
> New question #699959 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/699959
>
> I am trying to do e+e- process with madgraph.
> As recommended by 2111.02442, I choose the eva PDF.
> I also try to fix this with the patch https://bazaar.launchpad.net/~maddevelopers/mg5amcnlo/3.3.2/revision/976
> But it still leaves problems, and madgraph tells me to to check MG5_aMC_v3_3_1/bin/PROC_sm_0/error, where I find:
>
> Error: PDF not supported for pdg -11
>
> In MG5_aMC_v3_3_1/bin/PROC_sm_0/run_01_tag_1_debug.log , it is
>
> generate_events run_01
> Traceback (most recent call last):
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/extended_cmd.py", line 1544, in onecmd
> return self.onecmd_orig(line, **opt)
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/extended_cmd.py", line 1493, in onecmd_orig
> return func(arg, **opt)
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/madevent_interface.py", line 2362, in do_generate_events
> self.run_generate_events(switch_mode, args)
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/common_run_interface.py", line 7295, in new_fct
> original_fct(obj, *args, **opts)
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/madevent_interface.py", line 2401, in run_generate_events
> self.exec_cmd('survey %s %s' % (self.run_name,' '.join(args)),
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/extended_cmd.py", line 1573, in exec_cmd
> stop = Cmd.onecmd_orig(current_interface, line, **opt)
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/extended_cmd.py", line 1493, in onecmd_orig
> return func(arg, **opt)
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/interface/madevent_interface.py", line 3259, in do_survey
> jobs, P_zero_result = ajobcreator.get_helicity()
> File "/home/data/zhangrui/MG5_aMC_v3_3_1/madgraph/madevent/gen_ximprove.py", line 169, in get_helicity
> raise Exception(pjoin(self.me_dir,'error'))
> Exception: /home/data/zhangrui/MG5_aMC_v3_3_1/bin/PROC_sm_0/error
>
>
> I have made a simple example:
>
> generate e+ e- > t t~
> launch
> 0
> set ebeam 1500.0
> set lpp1 +3
> set lpp2 -3
> set pdlabel1 eva
> set pdlabel2 eva
> 0
> exit
>
> I know the madgraph version is different, and it is at different lines in madgraph/various/banner.py .
> SO is this a bug only for me, or maybe you can offer the 3.3.2 version?
>
> By the way, in 2108.10261, the PDF isronlyll , cepc240ll, clic3000ll, fcce240ll, fcce365ll and ilc500ll are also recommended, are they also OK? Because when I try them, they give me zero result.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks for explaining.

So if I want the initial state to be e+ e-, I should set pdlabel to something like clic3000ll?

Actually, when I try this w+ w- > t t~, madgraph gives me a very long error report:
-----------------------------------------------
Working on SubProcesses
INFO: P1_wpwm_ttx
INFO: Idle: 1, Running: 1, Completed: 0 [ current time: 05h16 ]
STOP 24
STOP 24
rm: cannot remove 'results.dat': No such file or directory
ERROR DETECTED
rm: cannot remove 'results.dat': No such file or directory
ERROR DETECTED
STOP 24
STOP 24
rm: cannot remove 'results.dat': No such file or directory
ERROR DETECTED
INFO: Idle: 0, Running: 1, Completed: 1 [ 0.034s ]
rm: cannot remove 'results.dat': No such file or directory
ERROR DETECTED
INFO: Idle: 0, Running: 0, Completed: 2 [ 0.036s ]
INFO: End survey
refine 10000
Creating Jobs
INFO: Refine results to 10000
INFO: Generating 10000.0 unweighted events.
Error when reading /home/data/zhangrui/MG5_aMC_v3_3_1/bin/PROC_sm_0/SubProcesses/P1_wpwm_ttx/G1/results.dat
Command "generate_events run_01" interrupted with error:
Exception : Reported error: End code 24.0
  Full associated log:
  Process in group number 1
  A PDF is used, so alpha_s(MZ) is going to be modified
  Old value of alpha_s from param_card: 0.11799999999999999
  New value of alpha_s from PDF eva : 0.11799999999999999
  Define smin to 119716.00000000000
  *****************************************************
  * MadGraph/MadEvent *
  * -------------------------------- *
  * http://madgraph.hep.uiuc.edu *
  * http://madgraph.phys.ucl.ac.be *
  * http://madgraph.roma2.infn.it *
  * -------------------------------- *
  * *
  * PARAMETER AND COUPLING VALUES *
  * *
  *****************************************************

   External Params
   ---------------------------------

  aEWM1 = 132.50700000000001
  mdl_Gf = 1.1663900000000000E-005
  aS = 0.11799999999999999
  mdl_ymb = 4.7000000000000002
  mdl_ymt = 173.00000000000000
  mdl_ymtau = 1.7769999999999999
  mdl_MZ = 91.188000000000002
  mdl_MT = 173.00000000000000
  mdl_MB = 4.7000000000000002
  mdl_MH = 125.00000000000000
  mdl_MTA = 1.7769999999999999
  mdl_WZ = 2.4414039999999999
  mdl_WW = 2.0476000000000001
  mdl_WT = 1.4915000000000000
  mdl_WH = 6.3823389999999999E-003
   Internal Params
   ---------------------------------

  mdl_conjg__CKM3x3 = 1.0000000000000000
  mdl_CKM3x3 = 1.0000000000000000
  mdl_conjg__CKM1x1 = 1.0000000000000000
  mdl_complexi = (0.0000000000000000,1.0000000000000000)
  mdl_MZ__exp__2 = 8315.2513440000002
  mdl_MZ__exp__4 = 69143404.913893804
  mdl_sqrt__2 = 1.4142135623730951
  mdl_MH__exp__2 = 15625.000000000000
  mdl_aEW = 7.5467711139788835E-003
  mdl_MW = 80.419002445756163
  mdl_sqrt__aEW = 8.6872153846781555E-002
  mdl_ee = 0.30795376724436879
  mdl_MW__exp__2 = 6467.2159543705357
  mdl_sw2 = 0.22224648578577766
  mdl_cw = 0.88190334743339216
  mdl_sqrt__sw2 = 0.47143025548407230
  mdl_sw = 0.47143025548407230
  mdl_g1 = 0.34919219678733299
  mdl_gw = 0.65323293034757990
  mdl_vev = 246.21845810181637
  mdl_vev__exp__2 = 60623.529110035903
  mdl_lam = 0.12886910601690263
  mdl_yb = 2.6995554250465490E-002
  mdl_yt = 0.99366614581500623
  mdl_ytau = 1.0206617000654717E-002
  mdl_muH = 88.388347648318430
  mdl_I1x33 = (2.69955542504654901E-002,0.0000000000000000)
  mdl_I2x33 = (0.99366614581500623,0.0000000000000000)
  mdl_I3x33 = (0.99366614581500623,0.0000000000000000)
  mdl_I4x33 = (2.69955542504654901E-002,0.0000000000000000)
  mdl_ee__exp__2 = 9.4835522759998875E-002
  mdl_sw__exp__2 = 0.22224648578577769
  mdl_cw__exp__2 = 0.77775351421422245
   Internal Params evaluated point by point
   ----------------------------------------

  mdl_sqrt__aS = 0.34351128074635334
  mdl_G__exp__2 = 1.4828317324943823
   Couplings of sm
   ---------------------------------

          GC_2 = 0.00000E+00 0.20530E+00
          GC_3 = -0.00000E+00 -0.30795E+00
         GC_50 = -0.00000E+00 -0.28804E+00
         GC_53 = 0.00000E+00 0.57609E+00
         GC_58 = -0.00000E+00 -0.27437E-01
         GC_72 = 0.00000E+00 0.52532E+02
         GC_94 = -0.00000E+00 -0.70263E+00
        GC_100 = 0.00000E+00 0.46191E+00

  Collider parameters:
  --------------------

  Running at e-e+ machine @ 3000.0000000000000 GeV
  PDF set = eva
  alpha_s(Mz)= 0.1180 running at 2 loops.
  alpha_s(Mz)= 0.1180 running at 2 loops.
  Renormalization scale set on event-by-event basis
  Factorization scales fixed @ 91.188000000000002 91.188000000000002

  getting user params
 Enter number of events and max and min iterations:
  Number of events and iterations 2000 5 3
 Enter desired fractional accuracy:
  Desired fractional accuracy: 0.10000000000000001
 Enter 0 for fixed, 2 for adjustable grid:
 Suppress amplitude (0 no, 1 yes)?
  Using suppressed amplitude.
 Exact helicity sum (0 yes, n = number/event)?
  Monte-Carlo over helicities

  ********************************************
  * You are using the DiscreteSampler module *
  * part of the MG5_aMC framework *
  * Author: Valentin Hirschi *
  ********************************************

 Enter Configuration Number:
 Running Configuration Number: 1
  Not subdividing B.W.
  Attempting mappinvarients 1 4
  Determine nb_t
  T-channel found: 0
  Completed mapping 4
  about to integrate 4 2000 5 3 4 1
  Using non-zero grid deformation.
   4 dimensions 2000 events 4 invarients 5 iterations 1 config(s), (0.99)
  Using h-tuple random number sequence.
  Error opening grid
  Using Uniform Grid! 16
  Using uniform alpha 1.0000000000000000
  Grid defined OK
  Set CM energy to 3000.00
  Mapping Graph 1 to config 1
  Determine nb_t
  T-channel found: 0
 Setting grid 1 0.13302E-01 1
  Transforming s_hat 1/s 3 1.3301777777777777E-002 119716.00000000000 9000000.0000000000
    1 1 2 3 4
  Masses: 0.804E+02 0.804E+02 0.173E+03 0.173E+03
 Using random seed offsets 1 : 1
   with seed 24
  Ranmar initialization seeds 31059 9398
   Particle 3 4
       Et > 0.0 0.0
        E > 0.0 0.0
      Eta < -1.0 -1.0
    xqcut: 0.0 0.0
 d R # 3 > -0.0 0.0
 s min # 3> 0.0 0.0
 xqcutij # 3> 0.0 0.0
  alpha_s for scale 183.07525459773058 is 0.10679978079868489
  Stopping EVA: QED charge violation with emission of vPID= 24 by fPID = 11
 STOP 24

 ls status:
 input_app.txt
 run1_app.log

Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/data/zhangrui/MG5_aMC_v3_3_1/bin/PROC_sm_0/run_01_tag_1_debug.log'.
Please attach this file to your report.
-----------------------------------------------
This happens even when I use this patch and also "set group_subprocesses False" (because it's reported if I do not set).
Follow that patch, I change Template/LO/Source/dsample.f in the same way, and in madgraph/various/banner.py the modification begin with line 3329, not 3331 (because of different version).

I think this problem maybe much more difficult to me, so I just focus on the e+ e- initial state. I download a new madgraph in case I change anything. And I try (this will report "zero cross section" if I use that patch. )

generate e+ e- > t t~
launch
0
set ebeam 1500.0
set lpp1 +3
set lpp2 -3
set pdlabel1 clic3000ll
set pdlabel2 clic3000ll
0

and this still leaves:

 Error: PDF not supported for pdg -11

in MG5_aMC_v3_3_1/bin/PROC_sm_0/error
This will still happen when I change the pdlabel from clic3000ll to none, or other PDFs.

For the eva mode, this happens when you wrongly set the identity of the beam (a w+ can not be part of an e-)

Concerning this:
generate e+ e- > t t~
launch
0
set ebeam 1500.0
set lpp1 +3
set lpp2 -3
set pdlabel1 clic3000ll
set pdlabel2 clic3000ll
0

This is indeed an issue fixed by the above patch, but you should be able to run this script:
generate e+ e- > t t~
launch
set ebeam 1500.0
set lpp1 +3
set lpp2 -3
set pdlabel clic3000ll

Now if you are interested in ISR, then it makes more sense to use isronlyll
since clic3000ll also includes beamstrahlung effect.

Cheers,

Olvier

Thanks!
I find I also set the lpp wrongly in e+ e- process, because lpp=3 means electron, which is e-. So the following script is OK

generate e+ e- > t t~
launch
0
set ebeam 1500.0
set lpp1 -3
set lpp2 +3
set pdlabel isronlyll
0
exit