bwcutoff affects SUSY cross section

Asked by Mike Hance

Dear experts,

We are generating some SUSY events with a focus on VBF-like signatures, but including both pure-EWK and mixed EWK/QCD diagrams to get the interference correct (see https://answers.launchpad.net/mg5amcnlo/+question/707582). One interesting effect we recently ran across was that the bwcutoff parameter in the job options seems to affect the cross section. The process we're generating is:

import model MSSM_SLHA2
define j = g u c d s u~ c~ d~ s~
define p = g u c d s u~ c~ d~ s~
generate p p > n2 x1+ j j QED=99 QCD=99 @1

If we set bwcutoff to 15, we get a cross section of 248 fb, while if we set it to 10000, we see a cross section of 207 fb. From reading https://answers.launchpad.net/mg5amcnlo/+faq/2014 we wouldn't expect the cross section to change at all, since we're not using the decay chain syntax nor restricting the diagrams at all. It turns out that the value of 10,000 was leftover from a previous setup, so we're not particularly attached to that, but we're worried that the dependence on bwcutoff reflects either some instability in the calculation or some misunderstanding on our part about how this should work.

I'll paste the full process, run, and param cards below in case that helps. We have been running in MadGraph 2.7.3, which we know is old... we can update to a newer release if it's known that there were any changes that might affect the conclusions here.

Thanks!

-Mike

====================================

import model MSSM_SLHA2
define j = g u c d s u~ c~ d~ s~
define p = g u c d s u~ c~ d~ s~
define susystrong = go ul ur dl dr cl cr sl sr t1 t2 b1 b2 ul~ ur~ dl~ dr~ cl~ cr~ sl~ sr~ t1~ t2~ b1~ b2~
generate p p > n2 x1+ j j QED=99 QCD=99 @1
output -f

-----------------------------------------------------

#*********************************************************************
# 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 *
# *
# Some of the values of variables can be list. These can either be *
# comma or space separated. *
#*********************************************************************
#
#*******************
# Running parameters
#*******************
#
#*********************************************************************
# Tag name for the run (one word) *
#*********************************************************************
  tag_1 = run_tag ! name of the run
#*********************************************************************
# 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. *
#*********************************************************************
  100000 = nevents ! Number of unweighted events requested
  0 = 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
     6500.0 = ebeam1 ! beam 1 total energy in GeV
     6500.0 = 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. *
#*********************************************************************
'lhapdf' = pdlabel ! PDF set
#247000 = lhaid ! if pdlabel=lhapdf, this is the lhapdf number
# nn23nlo = pdlabel ! PDF set, now NLO to match NLO runs
     260000 = lhaid ! if pdlabel=lhapdf, this is the lhapdf number, https://lhapdf.hepforge.org/pdfsets
#*********************************************************************
# 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 = dynamical_scale_choice ! Choose one of the preselected dynamical choices
 1.0 = scalefact ! scale factor for event-by-event scales
#*********************************************************************
# Type and output format
#*********************************************************************
  False = gridpack !True = setting up the grid pack
  -1.0 = time_of_flight ! threshold (in mm) below which the invariant lifetime is not written (-1 means not written)
  3.0 = lhe_version ! Change the way clustering information pass to shower.
  True = clusinfo ! include clustering tag in output
  average = event_norm ! average/sum. Normalization of the weight in the LHEF

#*********************************************************************
# Matching parameter (MLM only)
#*********************************************************************
 0 = ickkw ! 0 no matching, 1 MLM
 1.0 = alpsfact ! scale factor for QCD emission vx
 False = chcluster ! cluster only according to channel diag
 4 = asrwgtflavor ! highest quark flavor for a_s reweight
 False = auto_ptj_mjj ! Automatic setting of ptj and mjj if xqcut >0
                                   ! (turn off for VBF and single top processes)
 -1 = xqcut ! minimum kt jet measure between partons
#*********************************************************************
#
#*********************************************************************
# handling of the helicities:
# 0: sum over all helicities
# 1: importance sampling over helicities
#*********************************************************************
   0 = nhel ! using helicities importance sampling or not.
#*********************************************************************
# Generation bias, check the wiki page below for more information: *
# 'cp3.irmp.ucl.ac.be/projects/madgraph/wiki/LOEventGenerationBias' *
#*********************************************************************
 None = bias_module ! Bias type of bias, [None, ptj_bias, -custom_folder-]
 {} = bias_parameters ! Specifies the parameters of the module.
#
#*******************************
# Parton level cuts definition *
#*******************************
#
#
#*********************************************************************
# BW cutoff (M+/-bwcutoff*Gamma) ! Define on/off-shell for "$$" and decay
#*********************************************************************
  15 = bwcutoff ! (M+/-bwcutoff*Gamma)
#*********************************************************************
# Apply pt/E/eta/dr/mij/kt_durham cuts on decay products or not
# (note that etmiss/ptll/ptheavy/ht/sorted cuts always apply)
#*********************************************************************
   False = cut_decays ! Cut decay products
#*********************************************************************
# Standard Cuts *
#*********************************************************************
# Minimum and maximum pt's (for max, -1 means no cut) *
#*********************************************************************
 30 = ptj ! minimum pt for the jets
 20.0 = ptb ! minimum pt for the b
 10.0 = pta ! minimum pt for the photons
 2.0 = ptl ! minimum pt for the charged leptons
 0.0 = misset ! minimum missing Et (sum of neutrino's momenta)
 -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)
 {} = pt_min_pdg ! pt cut for other particles (use pdg code). Applied on particle and anti-particle
 {} = pt_max_pdg ! pt cut for other particles (syntax e.g. {6: 100, 25: 50})
#*********************************************************************
# 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
 {} = e_min_pdg ! E cut for other particles (use pdg code). Applied on particle and anti-particle
 {} = e_max_pdg ! E cut for other particles (syntax e.g. {6: 100, 25: 50})
#*********************************************************************
# Maximum and minimum absolute rapidity (for max, -1 means no cut) *
#*********************************************************************
  5 = etaj ! max rap for the jets
  -1.0 = etab ! max rap for the b
  -1.0 = etaa ! max rap for the photons
  -1.0 = etal ! max rap for the charged leptons
 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
 {} = eta_min_pdg ! rap cut for other particles (use pdg code). Applied on particle and anti-particle
 {} = eta_max_pdg ! rap cut for other particles (syntax e.g. {6: 2.5, 23: 5})
#*********************************************************************
# Minimum and maximum DeltaR distance *
#*********************************************************************
 0.0 = drjj ! min distance between jets
 0.0 = drbb ! min distance between b's
 0.0 = 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
 0.0 = 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 = 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 = 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
 {} = mxx_min_pdg ! min invariant mass of a pair of particles X/X~ (e.g. {6:250})
 {'default': False} = mxx_only_part_antipart ! if True the invariant mass is applied only
                       ! to pairs of particle/antiparticle and not to pairs of the same pdg codes.
#*********************************************************************
# 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 = ptheavy ! minimum pt for at least one heavy final state
 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 = 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 *
#*********************************************************************
 0.0 = ptl1min ! minimum pt for the leading lepton in pt
 0.0 = 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
 2.5 = deltaeta ! minimum rapidity for two jets in the WBF case
#***********************************************************************
# Turn on either the ktdurham or ptlund cut to activate *
# CKKW(L) merging with Pythia8 [arXiv:1410.3012, arXiv:1109.4829] *
#***********************************************************************
 -1 = ktdurham !
 0.4 = dparameter !
 -1.0 = ptlund !
 1, 2, 3, 4, 5, 6, 21 = pdgs_for_merging_cut ! PDGs for two cuts above
#*********************************************************************
# maximal pdg code for quark to be considered as a light jet *
# (otherwise b cuts are applied) *
#*********************************************************************
 4 = maxjetflavor ! Maximum jet pdg code
#*********************************************************************
#
#*********************************************************************
# Store info for systematics studies *
# WARNING: Do not use for interference type of computation *
#*********************************************************************
   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
# None = sys_alpsfact # \alpha_s emission scale factors
# auto = sys_matchscale # variation of merging scale
# PDF sets and number of members (0 or none for all members).
# NNPDF23_lo_as_0130_qed = sys_pdf # list of pdf sets
# MSTW2008nlo68cl.LHgrid 1 = sys_pdf
#

--------------------------------------------------------

######################################################################
## PARAM_CARD AUTOMATICALLY 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 DSQMIX
###################################
Block dsqmix
    1 1 1.000000e+00 # RRd1x1
    2 2 1.000000e+00 # RRd2x2
    3 3 9.387379e-01 # RRd3x3
    3 6 3.446319e-01 # RRd3x6
    4 4 1.000000e+00 # RRd4x4
    5 5 1.000000e+00 # RRd5x5
    6 3 -3.446319e-01 # RRd6x3
    6 6 9.387379e-01 # RRd6x6

###################################
## INFORMATION FOR FRALPHA
###################################
Block fralpha
    1 -1.138252e-01 # alp

###################################
## INFORMATION FOR HMIX
###################################
Block hmix
    1 3.576810e+02 # RMUH
    2 9.748624e+00 # tb
    4 1.664391e+05 # MA2

###################################
## INFORMATION FOR MASS
###################################
Block mass
    5 4.889917e+00 # MB
    6 1.750000e+02 # MT
   15 1.777000e+00 # Mta
   23 9.118760e+01 # MZ
   24 7.982901e+01 # MW
   25 1.108991e+02 # MH01
   35 4.5E9 # MH02
   36 4.5E9 # MA0
   37 4.5E9 # MH
   1000001 4.5E9 # set of param :1*Msd1, 1*Msd2
   1000002 4.5E9 # set of param :1*Msu1, 1*Msu2
   1000005 4.5E9 # Msd3
   1000006 4.5E9 # Msu3
   1000011 4.5E9 # set of param :1*Msl1, 1*Msl2
   1000012 4.5E9 # set of param :1*Msn1, 1*Msn2
   1000015 4.5E9 # Msl3
   1000016 4.5E9 # Msn3
   1000021 4.5E9 # Mgo
   1000022 99 # Mneu1
   1000023 100 # Mneu2
   1000024 100 # Mch1
   1000025 4.5E9 # Mneu3
   1000035 4.5E9 # Mneu4
   1000037 4.5E9 # Mch2
   2000001 4.5E9 # set of param :1*Msd4, 1*Msd5
   2000002 4.5E9 # set of param :1*Msu4, 1*Msu5
   2000005 4.5E9 # Msd6
   2000006 4.5E9 # Msu6
   2000011 4.5E9 # set of param :1*Msl4, 1*Msl5
   2000015 4.5E9 # Msl6
## 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
   1000014 4.5E9 # svm : Msn1
   1000013 4.5E9 # mul- : Msl1
   2000013 4.5E9 # mur- : Msl4
   1000004 4.5E9 # cl : Msu1
   2000004 4.5E9 # cr : Msu4
   1000003 4.5E9 # sl : Msd1
   2000003 4.5E9 # sr : Msd4

###################################
## INFORMATION FOR MSD2
###################################
Block msd2
    1 1 2.736847e+05 # set of param :1*RmD21x1, 1*RmD22x2
    2 2 2.736847e+05 # MG5 will not use this value use instead 1*mdl_RmD21x1
    3 3 2.702620e+05 # RmD23x3

###################################
## INFORMATION FOR MSE2
###################################
Block mse2
    1 1 1.863063e+04 # set of param :1*RmE21x1, 1*RmE22x2
    2 2 1.863063e+04 # MG5 will not use this value use instead 1*mdl_RmE21x1
    3 3 1.796764e+04 # RmE23x3

###################################
## INFORMATION FOR MSL2
###################################
Block msl2
    1 1 3.815567e+04 # set of param :1*RmL21x1, 1*RmL22x2
    2 2 3.815567e+04 # MG5 will not use this value use instead 1*mdl_RmL21x1
    3 3 3.782868e+04 # RmL23x3

###################################
## INFORMATION FOR MSOFT
###################################
Block msoft
    1 1.013965e+02 # RMx1
    2 1.915042e+02 # RMx2
    3 5.882630e+02 # RMx3
   21 3.233749e+04 # mHd2
   22 -1.288001e+05 # mHu2

###################################
## INFORMATION FOR MSQ2
###################################
Block msq2
    1 1 2.998367e+05 # set of param :1*RmQ21x1, 1*RmQ22x2
    2 2 2.998367e+05 # MG5 will not use this value use instead 1*mdl_RmQ21x1
    3 3 2.487654e+05 # RmQ23x3

###################################
## INFORMATION FOR MSU2
###################################
Block msu2
    1 1 2.803821e+05 # set of param :1*RmU21x1, 1*RmU22x2
    2 2 2.803821e+05 # MG5 will not use this value use instead 1*mdl_RmU21x1
    3 3 1.791371e+05 # RmU23x3

###################################
## INFORMATION FOR NMIX
###################################
Block nmix
   1 1 1.00E+00 # RNN1x1
   1 2 0.00E+00 # RNN1x2
   1 3 0.00E+00 # RNN1x3
   1 4 0.00E+00 # RNN1x4
   2 1 0.00E+00 # RNN2x1
   2 2 1.00E+00 # RNN2x2
   2 3 0.00E+00 # RNN2x3
   2 4 0.00E+00 # RNN2x4
   3 1 0.00E+00 # RNN3x1
   3 2 0.00E+00 # RNN3x2
   3 3 0.00E+00 # RNN3x3
   3 4 0.00E+00 # RNN3x4
   4 1 0.00E+00 # RNN4x1
   4 2 0.00E+00 # RNN4x2
   4 3 0.00E+00 # RNN4x3
   4 4 0.00E+00 # RNN4x4

###################################
## INFORMATION FOR SELMIX
###################################
Block selmix
    1 1 1.000000e+00 # RRl1x1
    2 2 1.000000e+00 # RRl2x2
    3 3 2.824872e-01 # RRl3x3
    3 6 9.592711e-01 # RRl3x6
    4 4 1.000000e+00 # RRl4x4
    5 5 1.000000e+00 # RRl5x5
    6 3 9.592711e-01 # RRl6x3
    6 6 -2.824872e-01 # RRl6x6

###################################
## INFORMATION FOR SMINPUTS
###################################
Block sminputs
    1 1.279340e+02 # aEWM1
    3 1.180000e-01 # aS

###################################
## INFORMATION FOR SNUMIX
###################################
Block snumix
    1 1 1.000000e+00 # RRn1x1
    2 2 1.000000e+00 # RRn2x2
    3 3 1.000000e+00 # RRn3x3

###################################
## INFORMATION FOR TD
###################################
Block td
    3 3 -1.106937e+02 # Rtd3x3

###################################
## INFORMATION FOR TE
###################################
Block te
    3 3 -2.540197e+01 # Rte3x3

###################################
## INFORMATION FOR TU
###################################
Block tu
    3 3 -4.447525e+02 # Rtu3x3

###################################
## INFORMATION FOR UMIX
###################################
Block umix
   1 1 1.00E+00 # RUU1x1
   1 2 0.00E+00 # RUU1x2
   2 1 0.00E+00 # RUU2x1
   2 2 0.00E+00 # RUU2x2

###################################
## INFORMATION FOR UPMNS
###################################
Block upmns
    1 1 1.000000e+00 # RMNS1x1
    2 2 1.000000e+00 # RMNS2x2
    3 3 1.000000e+00 # RMNS3x3

###################################
## INFORMATION FOR USQMIX
###################################
Block usqmix
    1 1 1.000000e+00 # RRu1x1
    2 2 1.000000e+00 # RRu2x2
    3 3 5.536450e-01 # RRu3x3
    3 6 8.327528e-01 # RRu3x6
    4 4 1.000000e+00 # RRu4x4
    5 5 1.000000e+00 # RRu5x5
    6 3 8.327528e-01 # RRu6x3
    6 6 -5.536450e-01 # RRu6x6

###################################
## INFORMATION FOR VCKM
###################################
Block vckm
    1 1 1.000000e+00 # RCKM1x1
    2 2 1.000000e+00 # RCKM2x2
    3 3 1.000000e+00 # RCKM3x3

###################################
## INFORMATION FOR VMIX
###################################
Block vmix
   1 1 1.00E+00 # RVV1x1
   1 2 0.00E+00 # RVV1x2
   2 1 0.00E+00 # RVV2x1
   2 2 0.00E+00 # RVV2x2

###################################
## INFORMATION FOR YD
###################################
Block yd
    3 3 1.388402e-01 # Ryd3x3

###################################
## INFORMATION FOR YE
###################################
Block ye
    3 3 1.008908e-01 # Rye3x3

###################################
## INFORMATION FOR YU
###################################
Block yu
    3 3 8.928445e-01 # Ryu3x3

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 1.561950e+00 # WT
DECAY 23 2.411433e+00 # WZ
DECAY 24 2.002822e+00 # WW
DECAY 25 1.986108e-03 # WH01
DECAY 35 5.748014e-01 # WH02
DECAY 36 6.321785e-01 # WA0
DECAY 37 5.469628e-01 # WH
DECAY 1000001 5.312788e+00 # Wsd1
DECAY 1000002 5.477195e+00 # Wsu1
DECAY 1000003 5.312788e+00 # Wsd2
DECAY 1000004 5.477195e+00 # Wsu2
DECAY 1000005 3.736276e+00 # Wsd3
DECAY 1000006 2.021596e+00 # Wsu3
DECAY 1000011 2.136822e-01 # Wsl1
DECAY 1000012 1.498816e-01 # Wsn1
DECAY 1000013 2.136822e-01 # Wsl2
DECAY 1000014 1.498816e-01 # Wsn2
DECAY 1000015 1.483273e-01 # Wsl3
DECAY 1000016 1.475190e-01 # Wsn3
DECAY 1000021 5.506754e+00 # Wgo
DECAY 1000023 9.37327589E-04 # neutralino2 decays
     1.00000000E+00 2 1000022 23 # BR(~chi_20 -> ~chi_10 Z )
DECAY 1000024 7.00367294E-03 # chargino1+ decays
     1.00000000E+00 2 1000022 24 # BR(~chi_1+ -> ~chi_10 w+)
DECAY 1000025 1.915985e+00 # Wneu3
DECAY 1000035 2.585851e+00 # Wneu4
DECAY 1000037 2.486895e+00 # Wch2
DECAY 2000001 2.858123e-01 # Wsd4
DECAY 2000002 1.152973e+00 # Wsu4
DECAY 2000003 2.858123e-01 # Wsd5
DECAY 2000004 1.152973e+00 # Wsu5
DECAY 2000005 8.015663e-01 # Wsd6
DECAY 2000006 7.373133e+00 # Wsu6
DECAY 2000011 2.161216e-01 # Wsl4
DECAY 2000013 2.161216e-01 # Wsl5
DECAY 2000015 2.699061e-01 # Wsl6
## 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 1000022 0.000000e+00 # n1 : 0.0
#===========================================================
# QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
#===========================================================

Block QNUMBERS 1000022 # n1
        1 0 # 3 times electric charge
        2 2 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 1000023 # n2
        1 0 # 3 times electric charge
        2 2 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 1000025 # n3
        1 0 # 3 times electric charge
        2 2 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 1000035 # n4
        1 0 # 3 times electric charge
        2 2 # number of spin states (2S+1)
        3 1 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 1000024 # x1+
        1 3 # 3 times electric charge
        2 2 # 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 1000037 # x2+
        1 3 # 3 times electric charge
        2 2 # 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 1000021 # go
        1 0 # 3 times electric charge
        2 2 # number of spin states (2S+1)
        3 8 # colour rep (1: singlet, 3: triplet, 8: octet)
        4 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 35 # h2
        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 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 36 # h3
        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 0 # Particle/Antiparticle distinction (0=own anti)
Block QNUMBERS 37 # h+
        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 1000012 # sve
        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 1000014 # svm
        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 1000016 # svt
        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 1000011 # el-
        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 1000013 # mul-
        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 1000015 # ta1-
        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 2000011 # er-
        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 2000013 # mur-
        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 2000015 # ta2-
        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 1000002 # ul
        1 2 # 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)
Block QNUMBERS 1000004 # cl
        1 2 # 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)
Block QNUMBERS 1000006 # t1
        1 2 # 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)
Block QNUMBERS 2000002 # ur
        1 2 # 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)
Block QNUMBERS 2000004 # cr
        1 2 # 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)
Block QNUMBERS 2000006 # t2
        1 2 # 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)
Block QNUMBERS 1000001 # dl
        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)
Block QNUMBERS 1000003 # sl
        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)
Block QNUMBERS 1000005 # b1
        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)
Block QNUMBERS 2000001 # dr
        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)
Block QNUMBERS 2000003 # sr
        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)
Block QNUMBERS 2000005 # b2
        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)

Question information

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Status:
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MadGraph5_aMC@NLO Edit question
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Solved by:
Olivier Mattelaer
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Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said :
#1

The phase-space parametrization of the numerical integrator does depend of that parameter.
In the infinite number of evaluation, the parametrization of the phase-space should does not affect the central value, it has impact on the error. Obviously we are far from such limit and if the parametrization is badly choose (I guess due to an unphysical choice of bwcutoff) then yes the result can be biased.

I'm trying to reproduce this with 2.9.16 (our LTS) to see
1) if this is still the case in that version (I might have decided to setup a maximum to that value for the phase-space parametrization)
2) if indeed the result is stable at low value and then start to miss some contribution.

Revision history for this message
Mike Hance (mhance) said :
#2

Interesting, thanks Olivier! This is good to know -- we sometimes use a large value just to keep intermediate particles in the event record, but if this affects the calculation then we'll definitely use smaller values in the future.

I did not see a big increase in the uncertainty of the cross section in either case, and it seemed slightly counterintuitive to me that relaxing the cutoff led to a lower cross section, but if this is entering at the level of the phase space parameterization then that may help explain why the sign of the difference isn't necessarily obvious.

Thanks again!

-Mike

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

Here is the result of my run (same param_card but default run_card)

bwcutoff cross-section
 5. 2.64(2)
 10 2.66(2)
 15 2.65(2)
 30 2.65(2)
 100 2.39(2)
 500 2.14(2)
 1000 2.13(2)
 5000 2.13(2)
 10000 2.13(2)

So yes the issue is still present within the long term stable version but you do have a nice float cross-section from 10 (likely 5) to 30.
So this is reasonable to me (i.e. we do not have the sensitivity on that parameter on the range of reasonable parameter and even bigger than that).

Cheers,

Olivier

Revision history for this message
Mike Hance (mhance) said :
#4

Thanks Olivier Mattelaer, that solved my question.