Problem with multiparticle process

Asked by Eleni Vryonidou on 2019-06-10

Hi Olivier,

I noticed a problem with multi particles, this time for a tree level process. I did:

import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5 # pass to 5 flavors
define j = p
define l+ = e+ mu+
define l- = e- mu-
generate h > z z > z l+ l- NP=2 QED=3 NP^2==2
output htoZllinter2

with the model from http://feynrules.irmp.ucl.ac.be/wiki/SMEFTatNLO

This computation crashes with a 0 cross-section error, whilst

import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5 # pass to 5 flavors
define j = p
generate h > z z > z e+ e- NP=2 QED=3 NP^2==2
add process h > z z > z mu+ mu- NP=2 QED=3 NP^2==2
output htoZllinter

works. I used the same param_card. See below.

Do you know why that is?

Thanks,

Eleni

######################################################################
## PARAM_CARD AUTOMATICALY GENERATED BY MG5 FOLLOWING UFO MODEL ####
######################################################################
## ##
## Width set on Auto will be computed following the information ##
## present in the decay.py files of the model. ##
## See arXiv:1402.1178 for more details. ##
## ##
######################################################################

###################################
## INFORMATION FOR CKMBLOCK
###################################
Block ckmblock
    1 2.277360e-01 # cabi

###################################
## INFORMATION FOR DIM6
###################################
Block dim6
    1 1.000000e+03 # Lambda
    2 2.000000e-10 # cpDC
    3 3.000000e-10 # cpWB
    4 4.000000e-10 # cdp
    5 5.000000e-10 # cp
    6 6.000000e-10 # cWWW
    7 7.000000e-10 # cG
    8 8.000000e-10 # cpG
    9 1.000000e-00 # cpW
   10 1.000000e-10 # cpBB

###################################
## INFORMATION FOR DIM62F
###################################
Block dim62f
    1 1.000000e-10 # cpl1
    2 2.000000e-10 # cpl2
    3 3.000000e-10 # cpl3
    4 4.000000e-10 # c3pl1
    5 5.000000e-10 # c3pl2
    6 6.000000e-10 # c3pl3
    7 7.000000e-10 # cpe
    8 8.000000e-10 # cpmu
    9 9.000000e-10 # cpta
   10 1.000000e-10 # cpqi
   11 1.100000e-10 # cpQ3
   12 1.200000e-10 # c3pqi
   13 1.300000e-10 # c3pQ3
   14 1.400000e-10 # cpu
   15 1.500000e-10 # cpt
   16 1.600000e-10 # cpd
   19 1.900000e-10 # ctp
   22 2.200000e-10 # ctB
   23 2.300000e-10 # ctW
   24 2.400000e-10 # ctG

###################################
## INFORMATION FOR DIM64F
###################################
Block dim64f
    1 1.000000e-10 # cQq83
    2 2.000000e-10 # cQq81
    3 3.000000e-10 # cQu8
    4 4.000000e-10 # ctq8
    6 6.000000e-10 # cQd8
    7 7.000000e-10 # ctu8
    8 8.000000e-10 # ctd8
   10 1.000000e-10 # cQq13
   11 1.100000e-10 # cQq11
   12 1.200000e-10 # cQu1
   13 1.300000e-10 # ctq1
   14 1.400000e-10 # cQd1
   16 1.600000e-10 # ctu1
   17 1.700000e-10 # ctd1
   19 1.900000e-10 # cQQ8
   20 2.000000e-10 # cQQ1
   21 2.100000e-10 # cQt1
   23 2.300000e-10 # ctt1
   25 2.500000e-10 # cQt8

###################################
## INFORMATION FOR DIM64F2L
###################################
Block dim64f2l
    1 1.000000e-10 # cQlM1
    2 2.000000e-10 # cQlM2
    3 3.000000e-10 # cQl31
    4 4.000000e-10 # cQl32
    5 5.000000e-10 # cQe
    6 6.000000e-10 # cQmu
    7 7.000000e-10 # ctl1
    8 8.000000e-10 # ctl2
    9 9.000000e-10 # cte
   10 1.000000e-10 # ctmu
   15 1.500000e-10 # cQlM3
   16 1.600000e-10 # cQl33
   17 1.700000e-10 # cQta
   18 1.800000e-10 # ctl3
   19 1.900000e-10 # ctta

###################################
## INFORMATION FOR DIM64F4L
###################################
Block dim64f4l
    1 1.000000e-10 # cll1111
    2 2.000000e-10 # cll2222
    3 3.000000e-10 # cll3333
    4 4.000000e-10 # cll1122
    5 5.000000e-10 # cll1133
    6 6.000000e-10 # cll2233
    7 7.000000e-10 # cll1221
    8 8.000000e-10 # cll1331
    9 9.000000e-10 # cll2332

###################################
## INFORMATION FOR LOOP
###################################
Block loop
    1 9.118800e+01 # MU_R

###################################
## INFORMATION FOR MASS
###################################
Block mass
    6 1.720000e+02 # MT
   23 9.118760e+01 # MZ
   24 7.982440e+01 # MW
   25 1.250000e+02 # MH
## Dependent parameters, given by model restrictions.
## Those values should be edited following the
## analytical expression. MG5 ignores those values
## but they are important for interfacing the output of MG5
## to external program such as Pythia.
  1 0.000000 # d : 0.0
  2 0.000000 # u : 0.0
  3 0.000000 # s : 0.0
  4 0.000000 # c : 0.0
  5 0.000000 # b : 0.0
  11 0.000000 # e- : 0.0
  12 0.000000 # ve : 0.0
  13 0.000000 # mu- : 0.0
  14 0.000000 # vm : 0.0
  15 0.000000 # ta- : 0.0
  16 0.000000 # vt : 0.0
  21 0.000000 # g : 0.0
  22 0.000000 # a : 0.0
  9000002 91.187600 # ghz : MZ
  9000003 79.824400 # ghwp : MW
  9000004 79.824400 # ghwm : MW

###################################
## INFORMATION FOR RENOR
###################################
Block renor
    1 5.550000e+02 # Mreno

###################################
## INFORMATION FOR SMINPUTS
###################################
Block sminputs
    2 1.166370e-05 # Gf
    3 1.184000e-01 # aS

###################################
## INFORMATION FOR YUKAWA
###################################
Block yukawa
    6 1.720000e+02 # ymt

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 1.508336e+00 # WT
DECAY 23 2.495200e+00 # WZ
DECAY 24 2.085000e+00 # WW
DECAY 25 5.753088e-03 # WH
## Dependent parameters, given by model restrictions.
## Those values should be edited following the
## analytical expression. MG5 ignores those values
## but they are important for interfacing the output of MG5
## to external program such as Pythia.
DECAY 1 0.000000 # d : 0.0
DECAY 2 0.000000 # u : 0.0
DECAY 3 0.000000 # s : 0.0
DECAY 4 0.000000 # c : 0.0
DECAY 5 0.000000 # b : 0.0
DECAY 11 0.000000 # e- : 0.0
DECAY 12 0.000000 # ve : 0.0
DECAY 13 0.000000 # mu- : 0.0
DECAY 14 0.000000 # vm : 0.0
DECAY 15 0.000000 # ta- : 0.0
DECAY 16 0.000000 # vt : 0.0
DECAY 21 0.000000 # g : 0.0
DECAY 22 0.000000 # a : 0.0
DECAY 9000002 2.495200 # ghz : WZ
DECAY 9000003 2.085000 # ghwp : WW
DECAY 9000004 2.085000 # ghwm : WW
#===========================================================
# QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
#===========================================================

Block QNUMBERS 9000001 # gha
        1 0 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000002 # ghz
        1 0 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000003 # ghwp
        1 3 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000004 # ghwm
        1 -3 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000005 # ghg
        1 0 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 8 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
2019-06-10
Last reply:
2019-06-10

Did you see a warning advising you to set group processes to false?

Is it also returning zero with that settings?

Cheers

Olivier

Get Outlook for iOS<https://aka.ms/o0ukef>
________________________________
From: <email address hidden> <email address hidden> on behalf of Eleni Vryonidou <email address hidden>
Sent: Monday, June 10, 2019 4:52:28 PM
To: Olivier Mattelaer
Subject: [Question #681319]: Problem with multiparticle process

New question #681319 on MadGraph5_aMC@NLO:
https://answers.launchpad.net/mg5amcnlo/+question/681319

Hi Olivier,

I noticed a problem with multi particles, this time for a tree level process. I did:

import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5 # pass to 5 flavors
define j = p
define l+ = e+ mu+
define l- = e- mu-
generate h > z z > z l+ l- NP=2 QED=3 NP^2==2
output htoZllinter2

with the model from http://feynrules.irmp.ucl.ac.be/wiki/SMEFTatNLO

This computation crashes with a 0 cross-section error, whilst

import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5 # pass to 5 flavors
define j = p
generate h > z z > z e+ e- NP=2 QED=3 NP^2==2
add process h > z z > z mu+ mu- NP=2 QED=3 NP^2==2
output htoZllinter

works. I used the same param_card. See below.

Do you know why that is?

Thanks,

Eleni

######################################################################
## PARAM_CARD AUTOMATICALY GENERATED BY MG5 FOLLOWING UFO MODEL ####
######################################################################
## ##
## Width set on Auto will be computed following the information ##
## present in the decay.py files of the model. ##
## See arXiv:1402.1178 for more details. ##
## ##
######################################################################

###################################
## INFORMATION FOR CKMBLOCK
###################################
Block ckmblock
    1 2.277360e-01 # cabi

###################################
## INFORMATION FOR DIM6
###################################
Block dim6
    1 1.000000e+03 # Lambda
    2 2.000000e-10 # cpDC
    3 3.000000e-10 # cpWB
    4 4.000000e-10 # cdp
    5 5.000000e-10 # cp
    6 6.000000e-10 # cWWW
    7 7.000000e-10 # cG
    8 8.000000e-10 # cpG
    9 1.000000e-00 # cpW
   10 1.000000e-10 # cpBB

###################################
## INFORMATION FOR DIM62F
###################################
Block dim62f
    1 1.000000e-10 # cpl1
    2 2.000000e-10 # cpl2
    3 3.000000e-10 # cpl3
    4 4.000000e-10 # c3pl1
    5 5.000000e-10 # c3pl2
    6 6.000000e-10 # c3pl3
    7 7.000000e-10 # cpe
    8 8.000000e-10 # cpmu
    9 9.000000e-10 # cpta
   10 1.000000e-10 # cpqi
   11 1.100000e-10 # cpQ3
   12 1.200000e-10 # c3pqi
   13 1.300000e-10 # c3pQ3
   14 1.400000e-10 # cpu
   15 1.500000e-10 # cpt
   16 1.600000e-10 # cpd
   19 1.900000e-10 # ctp
   22 2.200000e-10 # ctB
   23 2.300000e-10 # ctW
   24 2.400000e-10 # ctG

###################################
## INFORMATION FOR DIM64F
###################################
Block dim64f
    1 1.000000e-10 # cQq83
    2 2.000000e-10 # cQq81
    3 3.000000e-10 # cQu8
    4 4.000000e-10 # ctq8
    6 6.000000e-10 # cQd8
    7 7.000000e-10 # ctu8
    8 8.000000e-10 # ctd8
   10 1.000000e-10 # cQq13
   11 1.100000e-10 # cQq11
   12 1.200000e-10 # cQu1
   13 1.300000e-10 # ctq1
   14 1.400000e-10 # cQd1
   16 1.600000e-10 # ctu1
   17 1.700000e-10 # ctd1
   19 1.900000e-10 # cQQ8
   20 2.000000e-10 # cQQ1
   21 2.100000e-10 # cQt1
   23 2.300000e-10 # ctt1
   25 2.500000e-10 # cQt8

###################################
## INFORMATION FOR DIM64F2L
###################################
Block dim64f2l
    1 1.000000e-10 # cQlM1
    2 2.000000e-10 # cQlM2
    3 3.000000e-10 # cQl31
    4 4.000000e-10 # cQl32
    5 5.000000e-10 # cQe
    6 6.000000e-10 # cQmu
    7 7.000000e-10 # ctl1
    8 8.000000e-10 # ctl2
    9 9.000000e-10 # cte
   10 1.000000e-10 # ctmu
   15 1.500000e-10 # cQlM3
   16 1.600000e-10 # cQl33
   17 1.700000e-10 # cQta
   18 1.800000e-10 # ctl3
   19 1.900000e-10 # ctta

###################################
## INFORMATION FOR DIM64F4L
###################################
Block dim64f4l
    1 1.000000e-10 # cll1111
    2 2.000000e-10 # cll2222
    3 3.000000e-10 # cll3333
    4 4.000000e-10 # cll1122
    5 5.000000e-10 # cll1133
    6 6.000000e-10 # cll2233
    7 7.000000e-10 # cll1221
    8 8.000000e-10 # cll1331
    9 9.000000e-10 # cll2332

###################################
## INFORMATION FOR LOOP
###################################
Block loop
    1 9.118800e+01 # MU_R

###################################
## INFORMATION FOR MASS
###################################
Block mass
    6 1.720000e+02 # MT
   23 9.118760e+01 # MZ
   24 7.982440e+01 # MW
   25 1.250000e+02 # MH
## Dependent parameters, given by model restrictions.
## Those values should be edited following the
## analytical expression. MG5 ignores those values
## but they are important for interfacing the output of MG5
## to external program such as Pythia.
  1 0.000000 # d : 0.0
  2 0.000000 # u : 0.0
  3 0.000000 # s : 0.0
  4 0.000000 # c : 0.0
  5 0.000000 # b : 0.0
  11 0.000000 # e- : 0.0
  12 0.000000 # ve : 0.0
  13 0.000000 # mu- : 0.0
  14 0.000000 # vm : 0.0
  15 0.000000 # ta- : 0.0
  16 0.000000 # vt : 0.0
  21 0.000000 # g : 0.0
  22 0.000000 # a : 0.0
  9000002 91.187600 # ghz : MZ
  9000003 79.824400 # ghwp : MW
  9000004 79.824400 # ghwm : MW

###################################
## INFORMATION FOR RENOR
###################################
Block renor
    1 5.550000e+02 # Mreno

###################################
## INFORMATION FOR SMINPUTS
###################################
Block sminputs
    2 1.166370e-05 # Gf
    3 1.184000e-01 # aS

###################################
## INFORMATION FOR YUKAWA
###################################
Block yukawa
    6 1.720000e+02 # ymt

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 1.508336e+00 # WT
DECAY 23 2.495200e+00 # WZ
DECAY 24 2.085000e+00 # WW
DECAY 25 5.753088e-03 # WH
## Dependent parameters, given by model restrictions.
## Those values should be edited following the
## analytical expression. MG5 ignores those values
## but they are important for interfacing the output of MG5
## to external program such as Pythia.
DECAY 1 0.000000 # d : 0.0
DECAY 2 0.000000 # u : 0.0
DECAY 3 0.000000 # s : 0.0
DECAY 4 0.000000 # c : 0.0
DECAY 5 0.000000 # b : 0.0
DECAY 11 0.000000 # e- : 0.0
DECAY 12 0.000000 # ve : 0.0
DECAY 13 0.000000 # mu- : 0.0
DECAY 14 0.000000 # vm : 0.0
DECAY 15 0.000000 # ta- : 0.0
DECAY 16 0.000000 # vt : 0.0
DECAY 21 0.000000 # g : 0.0
DECAY 22 0.000000 # a : 0.0
DECAY 9000002 2.495200 # ghz : WZ
DECAY 9000003 2.085000 # ghwp : WW
DECAY 9000004 2.085000 # ghwm : WW
#===========================================================
# QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
#===========================================================

Block QNUMBERS 9000001 # gha
        1 0 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000002 # ghz
        1 0 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000003 # ghwp
        1 3 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000004 # ghwm
        1 -3 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 9000005 # ghg
        1 0 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 8 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)

--
You received this question notification because you are an answer
contact for MadGraph5_aMC@NLO.

Eleni Vryonidou (evryonidou) said : #2

No there was no warning.

I tried like this:

import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5 22 22 # pass to old flavors
define j = p
set group_subprocesses False
generate h > z z > z l+ l- NP=2 QED=3 NP^2==2
output testsub

but it fails again.

Eleni

You are using the latest version of the code right?

Olivier

> On 10 Jun 2019, at 17:57, Eleni Vryonidou <email address hidden> wrote:
>
> Question #681319 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/681319
>
> Status: Answered => Open
>
> Eleni Vryonidou is still having a problem:
> No there was no warning.
>
> I tried like this:
>
> import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
> define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5 22 22 # pass to old flavors
> define j = p
> set group_subprocesses False
> generate h > z z > z l+ l- NP=2 QED=3 NP^2==2
> output testsub
>
>
> but it fails again.
>
> Eleni
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Eleni Vryonidou (evryonidou) said : #4

I am using:

version = 2.6.5
date = 2018-02-03

I also tried in 3.0.0

Both fail with the card I attached.

Eleni

and you do not have this warning?

Computation of interference term with decay is not 100% validated.
                Please check carefully your result.
                One suggestion is also to compare the generation of your process with and without
                set group_subprocesses True
                (to write Before the generate command)

Now, I have try with and without multi-particle and it always return 0 result.
I have also run it in one of the development version, which distinguish the 0 result in two categories:
- the 0 which are due to 0 matrix-element
- the 0 which are due to the facts that the cuts removed all PS points (including issue with the PS generation in general).

In your case, the matrix-element is always evaluated to zero.
Are you sure that you put the correct benchmark for your comparison?

Cheers,

Olivier

> On 10 Jun 2019, at 21:08, Eleni Vryonidou <email address hidden> wrote:
>
> Question #681319 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/681319
>
> Status: Answered => Open
>
> Eleni Vryonidou is still having a problem:
> I am using:
>
> version = 2.6.5
> date = 2018-02-03
>
> I also tried in 3.0.0
>
> Both fail with the card I attached.
>
> Eleni
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Eleni Vryonidou (evryonidou) said : #6

Yes, I am sure my benchmark is ok, and Luca had exactly the same problem.

I don't see a warning, but in any case I am not using a decay syntax:

import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
generate h > z z > z e+ e- NP=2 QED=3 NP^2==2
output htozee

With my param_card it gives a number.

Then with l+ l- I get 0. Separately e+ e- and mu+ mu- give a non-zero number, but with multi particle I get 0....

Hi,

Not yet fully sure of what your issue is.
But I suceed to reproduce a similar issue.

Can you check with 2.6.6?
If you still have the issue can you try with setting nhel to 1 in the run_card?

Cheers,

Olivier

> On 10 Jun 2019, at 21:53, Eleni Vryonidou <email address hidden> wrote:
>
> Question #681319 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/681319
>
> Status: Answered => Open
>
> Eleni Vryonidou is still having a problem:
> Yes, I am sure my benchmark is ok, and Luca had exactly the same
> problem.
>
> I don't see a warning, but in any case I am not using a decay syntax:
>
> import model SMEFTatNLO_U2_2_U3_3_cG_4F_LO_UFO
> generate h > z z > z e+ e- NP=2 QED=3 NP^2==2
> output htozee
>
> With my param_card it gives a number.
>
> Then with l+ l- I get 0. Separately e+ e- and mu+ mu- give a non-zero
> number, but with multi particle I get 0....
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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