pole cancelation error for one charge conjugate

Asked by Holly Pacey

Hi,

I'm having problems with pole-cancelation errors for just one charge conjugate of a process.
I am running the NLO_LQ_S1 leptoquark model (https://lqnlo.hepforge.org/) with MG5_aMC_v2_9_4, trying to generate single leptoquark (s1m13) or antileptoquark (s1m13~) production at NLO. I am using a 4f proton.

This runs fine:
(1) generate p p > e+ s1m13 $$ s1m13~ [QCD]
Which includes diagrams starting with gu, gc, ...

but this fails with a pole cancellation error during the subprocess P0_gux_ems1m13x:
(2) generate p p > e- s1m13~ $$ s1m13 [QCD]
, which includes diagrams starting wtih gubar, gcbar, ...
"INFO: P0_gux_ems1m13x
INFO: Result for test_ME:
INFO: Passed.
INFO: Result for test_MC:
INFO: Passed.
INFO: Result for check_poles:
Error detected in "launch auto "
write debug file /usera/hp341/Emus/signal-production/StandaloneMadGraph_26/MG5_aMC_v2_9_4/test_both/run_01_tag_1_debug.log
If you need help with this issue please contact us on https://answers.launchpad.net/mg5amcnlo
str : Poles do not cancel, run cannot continue
"

It looks like (2) is successfully finding the charge conjugates of all the diagrams from (1), as I'd expect.
The problem happens running with both LO or NLO pdf sets.
The only difference I can see between (1) and (2) is the relative difference in diagram weights from the PDFs so I have no idea why it would fail only for (2). Perhaps there is a problem in the model itself but I am waiting to hear back from the authors.

I also checked with these options and it doesn't help:
set group_subprocesses Auto
set ignore_six_quark_processes False
set loop_optimized_output True
set gauge unitary
set complex_mass_scheme False

This is the run card contents:

#*******************
# Running parameters
#*******************
#
#***********************************************************************
# Tag name for the run (one word) *
#***********************************************************************
  tag_1 = run_tag ! name of the run
#***********************************************************************
# Number of LHE events (and their normalization) and the required *
# (relative) accuracy on the Xsec. *
# These values are ignored for fixed order runs *
#***********************************************************************
  10000 = nevents ! Number of unweighted events requested
  -1.0 = req_acc ! Required accuracy (-1=auto determined from nevents)
  -1 = nevt_job ! Max number of events per job in event generation.
                 ! (-1= no split).
#***********************************************************************
# Normalize the weights of LHE events such that they sum or average to *
# the total cross section *
#***********************************************************************
  average = event_norm ! valid settings: average, sum, bias
#***********************************************************************
# Number of points per itegration channel (ignored for aMC@NLO runs) *
#***********************************************************************
  0.01 = req_acc_fo ! Required accuracy (-1=ignored, and use the
                     ! number of points and iter. below)
# These numbers are ignored except if req_acc_FO is equal to -1
  5000 = npoints_fo_grid ! number of points to setup grids
  4 = niters_fo_grid ! number of iter. to setup grids
  10000 = npoints_fo ! number of points to compute Xsec
  6 = niters_fo ! number of iter. to compute Xsec
#***********************************************************************
# Random number seed *
#***********************************************************************
  0 = iseed ! rnd seed (0=assigned automatically=default))
#***********************************************************************
# Collider type and energy *
#***********************************************************************
  1 = lpp1 ! beam 1 type (0 = no PDF)
  1 = lpp2 ! beam 2 type (0 = no PDF)
  6500.0 = ebeam1 ! beam 1 energy in GeV
  6500.0 = ebeam2 ! beam 2 energy in GeV
#***********************************************************************
# PDF choice: this automatically fixes also alpha_s(MZ) and its evol. *
#***********************************************************************
  nn23nlo = pdlabel ! PDF set
  244600 = lhaid ! If pdlabel=lhapdf, this is the lhapdf number. Only
              ! numbers for central PDF sets are allowed. Can be a list;
              ! PDF sets beyond the first are included via reweighting.
#***********************************************************************
# Include the NLO Monte Carlo subtr. terms for the following parton *
# shower (HERWIG6 | HERWIGPP | PYTHIA6Q | PYTHIA6PT | PYTHIA8) *
# WARNING: PYTHIA6PT works only for processes without FSR!!!! *
#***********************************************************************
  HERWIG6 = parton_shower
  1.0 = shower_scale_factor ! multiply default shower starting
                                  ! scale by this factor
#***********************************************************************
# Renormalization and factorization scales *
# (Default functional form for the non-fixed scales is the sum of *
# the transverse masses divided by two of all final state particles *
# and partons. This can be changed in SubProcesses/set_scales.f or via *
# dynamical_scale_choice option) *
#***********************************************************************
  False = fixed_ren_scale ! if .true. use fixed ren scale
  False = fixed_fac_scale ! if .true. use fixed fac scale
  91.118 = mur_ref_fixed ! fixed ren reference scale
  91.118 = muf_ref_fixed ! fixed fact reference scale
  -1 = dynamical_scale_choice ! Choose one (or more) of the predefined
           ! dynamical choices. Can be a list; scale choices beyond the
           ! first are included via reweighting
  1.0 = mur_over_ref ! ratio of current muR over reference muR
  1.0 = muf_over_ref ! ratio of current muF over reference muF
#***********************************************************************
# Reweight variables for scale dependence and PDF uncertainty *
#***********************************************************************
  1.0, 2.0, 0.5 = rw_rscale ! muR factors to be included by reweighting
  1.0, 2.0, 0.5 = rw_fscale ! muF factors to be included by reweighting
  True = reweight_scale ! Reweight to get scale variation using the
            ! rw_rscale and rw_fscale factors. Should be a list of
            ! booleans of equal length to dynamical_scale_choice to
            ! specify for which choice to include scale dependence.
  False = reweight_pdf ! Reweight to get PDF uncertainty. Should be a
            ! list booleans of equal length to lhaid to specify for
            ! which PDF set to include the uncertainties.
#***********************************************************************
# Store reweight information in the LHE file for off-line model- *
# parameter reweighting at NLO+PS accuracy *
#***********************************************************************
  False = store_rwgt_info ! Store info for reweighting in LHE file
#***********************************************************************
# ickkw parameter: *
# 0: No merging *
# 3: FxFx Merging - WARNING! Applies merging only at the hard-event *
# level. After showering an MLM-type merging should be applied as *
# well. See http://amcatnlo.cern.ch/FxFx_merging.htm for details. *
# 4: UNLOPS merging (with pythia8 only). No interface from within *
# MG5_aMC available, but available in Pythia8. *
# -1: NNLL+NLO jet-veto computation. See arxiv:1412.8408 [hep-ph]. *
#***********************************************************************
  0 = ickkw
#***********************************************************************
#
#***********************************************************************
# BW cutoff (M+/-bwcutoff*Gamma). Determines which resonances are *
# written in the LHE event file *
#***********************************************************************
  15.0 = bwcutoff
#***********************************************************************
# Cuts on the jets. Jet clustering is performed by FastJet. *
# - When matching to a parton shower, these generation cuts should be *
# considerably softer than the analysis cuts. *
# - More specific cuts can be specified in SubProcesses/cuts.f *
#***********************************************************************
  1.0 = jetalgo ! FastJet jet algorithm (1=kT, 0=C/A, -1=anti-kT)
  0.7 = jetradius ! The radius parameter for the jet algorithm
  10.0 = ptj ! Min jet transverse momentum
  -1.0 = etaj ! Max jet abs(pseudo-rap) (a value .lt.0 means no cut)
#***********************************************************************
# Cuts on the charged leptons (e+, e-, mu+, mu-, tau+ and tau-) *
# More specific cuts can be specified in SubProcesses/cuts.f *
#***********************************************************************
  0.0 = ptl ! Min lepton transverse momentum
  -1.0 = etal ! Max lepton abs(pseudo-rap) (a value .lt.0 means no cut)
  0.0 = drll ! Min distance between opposite sign lepton pairs
  0.0 = drll_sf ! Min distance between opp. sign same-flavor lepton pairs
  0.0 = mll ! Min inv. mass of all opposite sign lepton pairs
  30.0 = mll_sf ! Min inv. mass of all opp. sign same-flavor lepton pairs
#***********************************************************************
# Photon-isolation cuts, according to hep-ph/9801442. When ptgmin=0, *
# all the other parameters are ignored. *
# More specific cuts can be specified in SubProcesses/cuts.f *
#***********************************************************************
  20.0 = ptgmin ! Min photon transverse momentum
  -1.0 = etagamma ! Max photon abs(pseudo-rap)
  0.4 = r0gamma ! Radius of isolation code
  1.0 = xn ! n parameter of eq.(3.4) in hep-ph/9801442
  1.0 = epsgamma ! epsilon_gamma parameter of eq.(3.4) in hep-ph/9801442
  True = isoem ! isolate photons from EM energy (photons and leptons)
#***********************************************************************
# Cuts associated to MASSIVE particles identified by their PDG codes. *
# All cuts are applied to both particles and anti-particles, so use *
# POSITIVE PDG CODES only. Example of the syntax is {6 : 100} or *
# {6:100, 25:200} for multiple particles *
#***********************************************************************
  {} = pt_min_pdg ! Min pT for a massive particle
  {} = pt_max_pdg ! Max pT for a massive particle
  {} = mxx_min_pdg ! inv. mass for any pair of (anti)particles
#***********************************************************************
# For aMCfast+APPLGRID use in PDF fitting (http://amcfast.hepforge.org)*
#***********************************************************************
  0 = iappl ! aMCfast switch (0=OFF, 1=prepare grids, 2=fill grids)
#***********************************************************************

This is the param_card contents:

###################################
## INFORMATION FOR MASS
###################################
Block mass
    5 4.700000e+00 # MB
    6 1.720000e+02 # MT
   15 1.777000e+00 # MTA
   23 9.118760e+01 # MZ
   25 1.250000e+02 # MH
  9000005 1.000000e+03 # MS1
## 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 0.000000e+00 # d : 0.0
  2 0.000000e+00 # u : 0.0
  3 0.000000e+00 # s : 0.0
  4 0.000000e+00 # c : 0.0
  11 0.000000e+00 # e- : 0.0
  12 0.000000e+00 # ve : 0.0
  13 0.000000e+00 # mu- : 0.0
  14 0.000000e+00 # vm : 0.0
  16 0.000000e+00 # vt : 0.0
  21 0.000000e+00 # g : 0.0
  22 0.000000e+00 # a : 0.0
  24 7.982436e+01 # w+ : cmath.sqrt(MZ__exp__2/2. + cmath.sqrt(MZ__exp__4/4. - (aEW*cmath.pi*MZ__exp__2)/(Gf*sqrt__2)))
  9000002 9.118760e+01 # ghz : MZ
  9000003 7.982436e+01 # ghwp : MW
  9000004 7.982436e+01 # ghwm : MW

###################################
## INFORMATION FOR SMINPUTS
###################################
Block sminputs
    1 1.279000e+02 # aEWM1
    2 1.166370e-05 # Gf
    3 1.184000e-01 # aS (Note that Parameter not used if you use a PDF set)

###################################
## INFORMATION FOR YUKAWA
###################################
Block yukawa
    5 4.700000e+00 # ymb
    6 1.720000e+02 # ymt
   15 1.777000e+00 # ymtau

###################################
## INFORMATION FOR YUKS1LL
###################################
Block yuks1ll
    1 1 1.000000e-04 # yLL1x1
    1 2 1.000000e-04 # yLL1x2
    1 3 1.000000e-04 # yLL1x3
    2 1 1.000000e-04 # yLL2x1
    2 2 1.000000e-04 # yLL2x2
    2 3 1.000000e-04 # yLL2x3
    3 1 1.000000e-04 # yLL3x1
    3 2 1.000000e-04 # yLL3x2
    3 3 1.000000e-04 # yLL3x3

###################################
## INFORMATION FOR YUKS1RR
###################################
Block yuks1rr
    1 1 1.000000e+00 # yRR1x1
    1 2 1.000000e-04 # yRR1x2
    1 3 1.000000e-04 # yRR1x3
    2 1 1.000000e-04 # yRR2x1
    2 2 1.000000e+00 # yRR2x2
    2 3 1.000000e-04 # yRR2x3
    3 1 1.000000e-04 # yRR3x1
    3 2 1.000000e-04 # yRR3x2
    3 3 1.000000e-04 # yRR3x3

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 1.508336e+00 # WT
DECAY 23 2.495200e+00 # WZ
DECAY 24 2.085000e+00 # WW
DECAY 25 4.070000e-03 # WH
DECAY 9000005 1.293000e+01 # WS1
## 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 0.000000e+00 # d : 0.0
DECAY 2 0.000000e+00 # u : 0.0
DECAY 3 0.000000e+00 # s : 0.0
DECAY 4 0.000000e+00 # c : 0.0
DECAY 5 0.000000e+00 # b : 0.0
DECAY 11 0.000000e+00 # e- : 0.0
DECAY 12 0.000000e+00 # ve : 0.0
DECAY 13 0.000000e+00 # mu- : 0.0
DECAY 14 0.000000e+00 # vm : 0.0
DECAY 15 0.000000e+00 # ta- : 0.0
DECAY 16 0.000000e+00 # vt : 0.0
DECAY 21 0.000000e+00 # g : 0.0
DECAY 22 0.000000e+00 # a : 0.0
DECAY 9000002 2.495200e+00 # ghz : WZ
DECAY 9000003 2.085000e+00 # ghwp : WW
DECAY 9000004 2.085000e+00 # 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 82 # 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)
Block QNUMBERS 9000005 # s1m13
        1 -1 # 3 times electric charge
        2 1 # number of spin states (2S+1)
        3 3 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 1 # Particle/Antiparticle distinction (0=own anti)

Thanks in Advance,
Holly

Question information

Language:
English Edit question
Status:
Needs information
For:
MadGraph5_aMC@NLO Edit question
Assignee:
marco zaro Edit question
Last query:
Last reply:
Revision history for this message
marco zaro (marco-zaro) said :
#1

Hi,
I tried to download the model. Once loaded, the commands
import model NLO_LQ_S1
generate p p > e+ s1m13 $$ s1m13~ [QCD]
give me the error
Command "generate p p > e+ s1m13 $$ s1m13~ [QCD]; output; launch NLO" interrupted in sub-command:
"generate p p > e+ s1m13 $$ s1m13~ [QCD]" with error:
InvalidCmd : No particle s1m13~ in mode

What am I doing wrong here?

Can you try to check if the pole mis-cancelation still occurs when all the widths are set to zero in the param_card?

Best,

Marco

Revision history for this message
Holly Pacey (hp341) said :
#2

Hi Marco,

Thanks for the quick reply. Try s1m13* not s1m13~ for the antiparticle.

It does print out this in the log so is at least setting the leptoquark width to zero:
INFO: For gauge cancellation, the width of 'S1m13' has been set to zero.

I just tried setting all the widths in the param_card to 0, and the error looks unchanged.

Best,
Holly

Revision history for this message
marco zaro (marco-zaro) said (last edit ):
#3

Hi,
Having a look at the check_poles log, I see this for the last point of the process which passes (the directory is P0_gu_eps1m13):

  BORN 4.5378296774771873E-004
  SINGLE POLE (MadFKS) -6.4180695407623674E-006
  DOUBLE POLE (MadFKS) -3.7054599422110439E-005
  SINGLE POLE (MadLoop) -6.4180695407623098E-006
  DOUBLE POLE (MadLoop) -3.7054599422110351E-005
  FINITE PART (MadLoop) 1.0430129687740848E-004
    650.00000000000000 0.0000000000000000 0.0000000000000000 650.00000000000000 0.0000000000000000
    650.00000000000000 0.0000000000000000 0.0000000000000000 -650.00000000000000 0.0000000000000000
    487.50000000000011 -461.40033139774681 -153.08286762648672 36.491366448804179 0.0000000000000000
    812.49999999999989 461.40033139774664 153.08286762648675 -36.491366448804122 650.00000000000000

while for the process which fails (in the charge-conjugated directory, P0_gux_ems1m13*) I get

  BORN 4.5378296774771873E-004
  SINGLE POLE (MadFKS) -6.4180695407623674E-006
  DOUBLE POLE (MadFKS) -3.7054599422110439E-005
  SINGLE POLE (MadLoop) -2.2967096852760531E-005
  DOUBLE POLE (MadLoop) -3.7054599422110338E-005
  FINITE PART (MadLoop) 7.4689486294079118E-005
    650.00000000000000 0.0000000000000000 0.0000000000000000 650.00000000000000 0.0000000000000000
    650.00000000000000 0.0000000000000000 0.0000000000000000 -650.00000000000000 0.0000000000000000
    487.50000000000011 -461.40033139774681 -153.08286762648672 36.491366448804179 0.0000000000000000
    812.49999999999989 461.40033139774664 153.08286762648675 -36.491366448804122 650.00000000000000

As you can see, the PS point is the same, and this gives the same Born as well as the same poles computed by MadFKS (i.e. using their known from, e.g https://arxiv.org/pdf/0908.4272.pdf, eq B2). The double pole by Madloop is also the same, while this is not the case for the single pole, hence the failure. I thus suspect there is some problem with the UV/R2 counterterms of the model.
I suggest you to contact the authors, mentioning this question so that they can have a look.

Please post here the outcome, so that this is documented for everybody

Best wishes,

marco

Revision history for this message
Holly Pacey (hp341) said :
#4

Hi Marco,

Thank you for spotting this! I have contacted the authors and will post the outcome.

Best wishes,
Holly

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