MadGraph5_aMC@NLO

Madgraph deleting events in WWjjj matched production

Asked by Jeff Asaf Dror

I'm trying to use Madgraph to calculate same sign W production with 3 jets (matched) and I'm finding that it usually doesn't give the expected number of events upon completion of the run (I say usually because one time I did this I did get the expected number of events). I understand that usually missing events indicates a divergence in the amplitude but I don't think this should be the case as we have applied sensible cuts at the run level. I've tried to reproduce this using many other similar configurations but unfortunately have not managed to isolate the problem. I've tried this on Madgraph v2.2.3 and Madgraph v2.3.0 and both have the same issue.

The exact steps i've used to result in the issue are:
  define p = p b b~
  define j = p
  generate p p > w+ w+ j j j, w+ > l+ vl, w+ > l+ vl @1
  add process p p > w- w- j j j, w- > l- vl~, w- > l- vl~ @2
  output WW_3j_matched

I've also attached the run_card.dat in case this helps.

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Jeff Asaf Dror (asafjeffdror) said : 		#2

#*********************************************************************
# MadGraph5_aMC@NLO *
# *
# run_card.dat MadEvent *
# *
# This file is used to set the parameters of the run. *
# *
# Some notation/conventions: *
# *
# Lines starting with a '# ' are info or comments *
# *
# mind the format: value = variable ! comment *
#*********************************************************************
#
#*******************
# Running parameters
#*******************
#
#*********************************************************************
# Tag name for the run (one word) *
#*********************************************************************
  tag_1 = run_tag ! name of the run
#*********************************************************************
# Run to generate the grid pack *
#*********************************************************************
  False = gridpack !True = setting up the grid pack
#*********************************************************************
# Number of events and rnd seed *
# Warning: Do not generate more than 1M events in a single run *
# If you want to run Pythia, avoid more than 50k events in a run. *
#*********************************************************************
  50000 = nevents ! Number of unweighted events requested
 21 = iseed ! rnd seed (0=assigned automatically=default))
#*********************************************************************
# Collider type and energy *
# lpp: 0=No PDF, 1=proton, -1=antiproton, 2=photon from proton, *
# 3=photon from electron *
#*********************************************************************
  1 = lpp1 ! beam 1 type
  1 = lpp2 ! beam 2 type
  4000.0 = ebeam1 ! beam 1 total energy in GeV
  4000.0 = ebeam2 ! beam 2 total energy in GeV
#*********************************************************************
# Beam polarization from -100 (left-handed) to 100 (right-handed) *
#*********************************************************************
  0.0 = polbeam1 ! beam polarization for beam 1
  0.0 = polbeam2 ! beam polarization for beam 2
#*********************************************************************
# PDF CHOICE: this automatically fixes also alpha_s and its evol. *
#*********************************************************************
  nn23lo1 = pdlabel ! PDF set
  230000 = lhaid ! if pdlabel=lhapdf, this is the lhapdf number
#*********************************************************************
# Renormalization and factorization scales *
#*********************************************************************
  False = fixed_ren_scale ! if .true. use fixed ren scale
  False = 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
  1.0 = scalefact ! scale factor for event-by-event scales
#*********************************************************************
# Matching - Warning! ickkw > 1 is still beta
#*********************************************************************
  1 = ickkw ! 0 no matching, 1 MLM, 2 CKKW matching
  1 = highestmult ! for ickkw=2, highest mult group
  1 = ktscheme ! for ickkw=1, 1 Durham kT, 2 Pythia pTE
  1 = alpsfact ! scale factor for QCD emission vx
  False = chcluster ! cluster only according to channel diag
  True = pdfwgt ! for ickkw=1, perform pdf reweighting
  5 = asrwgtflavor ! highest quark flavor for a_s reweight
  True = clusinfo ! include clustering tag in output
  3.0 = lhe_version ! Change the way clustering information pass to shower.
#*********************************************************************
#**********************************************************
#
#**********************************************************
# Automatic ptj and mjj cuts if xqcut > 0
# (turn off for VBF and single top processes)
#**********************************************************
  True = auto_ptj_mjj ! Automatic setting of ptj and mjj
#**********************************************************
#
#**********************************
# BW cutoff (M+/-bwcutoff*Gamma)
#**********************************
  15.0 = bwcutoff ! (M+/-bwcutoff*Gamma)
#**********************************************************
# Apply pt/E/eta/dr/mij cuts on decay products or not
# (note that etmiss/ptll/ptheavy/ht/sorted cuts always apply)
#**********************************************************
  True = cut_decays ! Cut decay products
#*************************************************************
# Number of helicities to sum per event (0 = all helicities)
# 0 gives more stable result, but longer run time (needed for
# long decay chains e.g.).
# Use >=2 if most helicities contribute, e.g. pure QCD.
#*************************************************************
  0 = nhel ! Number of helicities used per event
#*******************
# Standard Cuts
#*******************
#
#*********************************************************************
# Minimum and maximum pt's (for max, -1 means no cut) *
#*********************************************************************
  30.0 = ptj ! minimum pt for the jets
  30.0 = ptb ! minimum pt for the b
  0.0 = pta ! minimum pt for the photons
  0.0 = ptl ! minimum pt for the charged leptons
  0.0 = misset ! minimum missing Et (sum of neutrino's momenta)
  0.0 = ptheavy ! minimum pt for one heavy final state
  1.0 = ptonium ! minimum pt for the quarkonium states
  -1.0 = ptjmax ! maximum pt for the jets
  -1.0 = ptbmax ! maximum pt for the b
  -1.0 = ptamax ! maximum pt for the photons
  -1.0 = ptlmax ! maximum pt for the charged leptons
  -1.0 = missetmax ! maximum missing Et (sum of neutrino's momenta)
#*********************************************************************
# Minimum and maximum E's (in the center of mass frame) *
#*********************************************************************
  0.0 = ej ! minimum E for the jets
  0.0 = eb ! minimum E for the b
  0.0 = ea ! minimum E for the photons
  0.0 = el ! minimum E for the charged leptons
  -1.0 = ejmax ! maximum E for the jets
  -1.0 = ebmax ! maximum E for the b
  -1.0 = eamax ! maximum E for the photons
  -1.0 = elmax ! maximum E for the charged leptons
#*********************************************************************
# Maximum and minimum absolute rapidity (for max, -1 means no cut) *
#*********************************************************************
  5.0 = etaj ! max rap for the jets
  5.0 = etab ! max rap for the b
  -1.0 = etaa ! max rap for the photons
  2.5 = etal ! max rap for the charged leptons
  0.6 = etaonium ! max rap for the quarkonium states
  0.0 = etajmin ! min rap for the jets
  0.0 = etabmin ! min rap for the b
  0.0 = etaamin ! min rap for the photons
  0.0 = etalmin ! main rap for the charged leptons
#*********************************************************************
# Minimum and maximum DeltaR distance *
#*********************************************************************
  0.0 = drjj ! min distance between jets
  0.0 = drbb ! min distance between b's
  0.3 = drll ! min distance between leptons
  0.0 = draa ! min distance between gammas
  0.0 = drbj ! min distance between b and jet
  0.0 = draj ! min distance between gamma and jet
  0.3 = drjl ! min distance between jet and lepton
  0.0 = drab ! min distance between gamma and b
  0.0 = drbl ! min distance between b and lepton
  0.0 = dral ! min distance between gamma and lepton
  -1.0 = drjjmax ! max distance between jets
  -1.0 = drbbmax ! max distance between b's
  -1.0 = drllmax ! max distance between leptons
  -1.0 = draamax ! max distance between gammas
  -1.0 = drbjmax ! max distance between b and jet
  -1.0 = drajmax ! max distance between gamma and jet
  -1.0 = drjlmax ! max distance between jet and lepton
  -1.0 = drabmax ! max distance between gamma and b
  -1.0 = drblmax ! max distance between b and lepton
  -1.0 = dralmax ! maxdistance between gamma and lepton
#*********************************************************************
# Minimum and maximum invariant mass for pairs *
# WARNING: for four lepton final state mmll cut require to have *
# different lepton masses for each flavor! *
#*********************************************************************
  0.0 = mmjj ! min invariant mass of a jet pair
  0.0 = mmbb ! min invariant mass of a b pair
  0.0 = mmaa ! min invariant mass of gamma gamma pair
  0.0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
  -1.0 = mmjjmax ! max invariant mass of a jet pair
  -1.0 = mmbbmax ! max invariant mass of a b pair
  -1.0 = mmaamax ! max invariant mass of gamma gamma pair
  -1.0 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair
#*********************************************************************
# Minimum and maximum invariant mass for all letpons *
#*********************************************************************
  0.0 = mmnl ! min invariant mass for all letpons (l+- and vl)
  -1.0 = mmnlmax ! max invariant mass for all letpons (l+- and vl)
#*********************************************************************
# Minimum and maximum pt for 4-momenta sum of leptons *
#*********************************************************************
  0.0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
  -1.0 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)
#*********************************************************************
# Inclusive cuts *
#*********************************************************************
  0.0 = xptj ! minimum pt for at least one jet
  0.0 = xptb ! minimum pt for at least one b
  0.0 = xpta ! minimum pt for at least one photon
  0.0 = xptl ! minimum pt for at least one charged lepton
#*********************************************************************
# Control the pt's of the jets sorted by pt *
#*********************************************************************
  0.0 = ptj1min ! minimum pt for the leading jet in pt
  0.0 = ptj2min ! minimum pt for the second jet in pt
  0.0 = ptj3min ! minimum pt for the third jet in pt
  0.0 = ptj4min ! minimum pt for the fourth jet in pt
  -1.0 = ptj1max ! maximum pt for the leading jet in pt
  -1.0 = ptj2max ! maximum pt for the second jet in pt
  -1.0 = ptj3max ! maximum pt for the third jet in pt
  -1.0 = ptj4max ! maximum pt for the fourth jet in pt
  0 = cutuse ! reject event if fails any (0) / all (1) jet pt cuts
#*********************************************************************
# Control the pt's of leptons sorted by pt *
#*********************************************************************
  30.0 = ptl1min ! minimum pt for the leading lepton in pt
  30.0 = ptl2min ! minimum pt for the second lepton in pt
  0.0 = ptl3min ! minimum pt for the third lepton in pt
  0.0 = ptl4min ! minimum pt for the fourth lepton in pt
  -1.0 = ptl1max ! maximum pt for the leading lepton in pt
  -1.0 = ptl2max ! maximum pt for the second lepton in pt
  -1.0 = ptl3max ! maximum pt for the third lepton in pt
  -1.0 = ptl4max ! maximum pt for the fourth lepton in pt
#*********************************************************************
# Control the Ht(k)=Sum of k leading jets *
#*********************************************************************
  0.0 = htjmin ! minimum jet HT=Sum(jet pt)
  -1.0 = htjmax ! maximum jet HT=Sum(jet pt)
  0.0 = ihtmin !inclusive Ht for all partons (including b)
  -1.0 = ihtmax !inclusive Ht for all partons (including b)
  0.0 = ht2min ! minimum Ht for the two leading jets
  0.0 = ht3min ! minimum Ht for the three leading jets
  0.0 = ht4min ! minimum Ht for the four leading jets
  -1.0 = ht2max ! maximum Ht for the two leading jets
  -1.0 = ht3max ! maximum Ht for the three leading jets
  -1.0 = ht4max ! maximum Ht for the four leading jets
#***********************************************************************
# Photon-isolation cuts, according to hep-ph/9801442 *
# When ptgmin=0, all the other parameters are ignored *
# When ptgmin>0, pta and draj are not going to be used *
#***********************************************************************
  0.0 = ptgmin ! Min photon transverse momentum
  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)
#*********************************************************************
# WBF cuts *
#*********************************************************************
  0.0 = xetamin ! minimum rapidity for two jets in the WBF case
  0.0 = deltaeta ! minimum rapidity for two jets in the WBF case
#*********************************************************************
# KT DURHAM CUT *
#*********************************************************************
  -1.0 = ktdurham
   0.4 = dparameter
 #*********************************************************************
# maximal pdg code for quark to be considered as a light jet *
# (otherwise b cuts are applied) *
#*********************************************************************
  5 = maxjetflavor ! Maximum jet pdg code
#*********************************************************************
# Jet measure cuts *
#*********************************************************************
  30.0 = xqcut ! minimum kt jet measure between partons
#*********************************************************************
#
#*********************************************************************
# Store info for systematics studies *
# WARNING: If use_syst is T, matched Pythia output is *
# meaningful ONLY if plotted taking matchscale *
# reweighting into account! *
#*********************************************************************
  False = use_syst ! Enable systematics studies
#
#**************************************
# Parameter of the systematics study
# will be used by SysCalc (if installed)
#**************************************
#
  0.5 1 2 = sys_scalefact # factorization/renormalization scale factor
  0.5 1 2 = sys_alpsfact # \alpha_s emission scale factors
  30 50 = sys_matchscale # variation of merging scale
# PDF sets and number of members (0 or none for all members).
  CT10nlo.LHgrid = sys_pdf # matching scales
# MSTW2008nlo68cl.LHgrid 1 = sys_pdf

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#3

Hi,

This is likely a problem with the phase-space generator. We have an idea how to fix this but this will take time.

Cheers,

Olivier

Revision history for this message
Jeff Asaf Dror (asafjeffdror) said : 		#4

Thanks for the quick response. That's good to know. In the mean time should we expect this would bias our result or should we just run more events?

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#5

Hi,

Running with more events should be fine.

Cheers,

Olivier

On 04 Aug 2015, at 12:36, Jeff Asaf Dror <email address hidden> wrote:

> Question #269969 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/269969
>
> Status: Answered => Open
>
> Jeff Asaf Dror is still having a problem:
> Thanks for the quick response. That's good to know. In the mean time
> should we expect this would bias our result or should we just run more
> events?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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