zero cross section vertex (AZHH) of EWdim6

Hi,

This is a problem of the phase-space integrator. all the channel of integration are based on the three point vertices.
Since in your case they are all zero, then the phase-space integration fails and returns zero.
The solution is to remove all the zero from the matrix-element by using a restricted model.

for EWdim6, this is very simple to do by doing the following
import model EWdim6
customize_model —save=CBL2_CWL2
then the code will propose to you a series of switch to remove/add some operator.

after that you can do
import model EWdim6-CBL2_CWL2

and that optimised model should not create trouble to be integrated.

Cheers,

Olivier

On 10 Aug 2015, at 12:56, Soyoung Shim <email address hidden> wrote:

> New question #270192 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/270192
>
>
> I would like to check how much each 6 dim operators contribute to the vertex, [AZHH].
> So, I set CBL2 and CWL2 as 1 and the others as 0.
> And the result became 0.
>
> I checked model files: couplings.py; vertices.py and lorentz.py .
> There exist the contribution from these operators corresponding to CBL2 and CWL2.
> Then why did the result become 0?
>
> Here is the tag.
> And then I add some parts from the model files of EWdim6.
>
> And.. how does MG handle the cut off scale lambda in this 6 dimensional model?
>
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------
> ===================================================================================================
> <LesHouchesEvents version="3.0">
> <header>
> <!--
> #*********************************************************************
> # *
> # MadGraph5_aMC@NLO *
> # *
> # Going Beyond *
> # *
> # http://madgraph.hep.uiuc.edu *
> # http://madgraph.phys.ucl.ac.be *
> # http://amcatnlo.cern.ch *
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> # *
> #....................................................................*
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> # This file contains all the information necessary to reproduce *
> # the events generated: *
> # *
> # 1. software version *
> # 2. proc_card : code generation info including model *
> # 3. param_card : model primary parameters in the LH format *
> # 4. run_card : running parameters (collider and cuts) *
> # 5. pythia_card : present only if pythia has been run *
> # 6. pgs_card : present only if pgs has been run *
> # 7. delphes_cards : present only if delphes has been run *
> # *
> # *
> #*********************************************************************
> -->
> <MGVersion>
> 2.2.3
> </MGVersion>
> <MG5ProcCard>
> #************************************************************
> #* MadGraph5_aMC@NLO *
> #* *
> #* * * *
> #* * * * * *
> #* * * * * 5 * * * * *
> #* * * * * *
> #* * * *
> #* *
> #* *
> #* VERSION 2.2.3 2015-02-10 *
> #* *
> #* The MadGraph5_aMC@NLO Development Team - Find us at *
> #* https://server06.fynu.ucl.ac.be/projects/madgraph *
> #* *
> #************************************************************
> #* *
> #* Command File for MadGraph5_aMC@NLO *
> #* *
> #* run as ./bin/mg5_aMC filename *
> #* *
> #************************************************************
> set group_subprocesses Auto
> set ignore_six_quark_processes False
> set loop_optimized_output True
> set gauge unitary
> set complex_mass_scheme False
> import model sm
> define p = g u c d s u~ c~ d~ s~
> define j = g u c d s u~ c~ d~ s~
> define l+ = e+ mu+
> define l- = e- mu-
> define vl = ve vm vt
> define vl~ = ve~ vm~ vt~
> import model EWdim6
> import model EWdim6-full
> generate h h > a z / a h z
> output hhaz-ew6
> </MG5ProcCard>
> <MGRunCard>
> #*********************************************************************
> # 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. *
> #*********************************************************************
> 10000 = 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 *
> #*********************************************************************
> 0 = lpp1 ! beam 1 type
> 0 = lpp2 ! beam 2 type
> 500 = ebeam1 ! beam 1 total energy in GeV
> 500 = ebeam2 ! beam 2 total energy in GeV
> #*********************************************************************
> # Beam polarization from -100 (left-handed) to 100 (right-handed) *
> #*********************************************************************
> 0 = polbeam1 ! beam polarization for beam 1
> 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 *
> #*********************************************************************
> F = fixed_ren_scale ! if .true. use fixed ren scale
> F = fixed_fac_scale ! if .true. use fixed fac scale
> 91.1880 = scale ! fixed ren scale
> 91.1880 = dsqrt_q2fact1 ! fixed fact scale for pdf1
> 91.1880 = dsqrt_q2fact2 ! fixed fact scale for pdf2
> 1 = scalefact ! scale factor for event-by-event scales
> #*********************************************************************
> # Matching - Warning! ickkw > 1 is still beta
> #*********************************************************************
> 0 = 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
> F = chcluster ! cluster only according to channel diag
> T = pdfwgt ! for ickkw=1, perform pdf reweighting
> 5 = asrwgtflavor ! highest quark flavor for a_s reweight
> T = 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)
> #**********************************************************
> T = auto_ptj_mjj ! Automatic setting of ptj and mjj
> #**********************************************************
> #
> #**********************************
> # BW cutoff (M+/-bwcutoff*Gamma)
> #**********************************
> 15 = 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)
> #**********************************************************
> T = 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) *
> #*********************************************************************
> 20 = ptj ! minimum pt for the jets
> 0 = ptb ! minimum pt for the b
> 10 = pta ! minimum pt for the photons
> 10 = ptl ! minimum pt for the charged leptons
> 0 = misset ! minimum missing Et (sum of neutrino's momenta)
> 0 = ptheavy ! minimum pt for one heavy final state
> 1.0 = ptonium ! minimum pt for the quarkonium states
> -1 = ptjmax ! maximum pt for the jets
> -1 = ptbmax ! maximum pt for the b
> -1 = ptamax ! maximum pt for the photons
> -1 = ptlmax ! maximum pt for the charged leptons
> -1 = missetmax ! maximum missing Et (sum of neutrino's momenta)
> #*********************************************************************
> # Minimum and maximum E's (in the center of mass frame) *
> #*********************************************************************
> 0 = ej ! minimum E for the jets
> 0 = eb ! minimum E for the b
> 0 = ea ! minimum E for the photons
> 0 = el ! minimum E for the charged leptons
> -1 = ejmax ! maximum E for the jets
> -1 = ebmax ! maximum E for the b
> -1 = eamax ! maximum E for the photons
> -1 = elmax ! maximum E for the charged leptons
> #*********************************************************************
> # Maximum and minimum absolute rapidity (for max, -1 means no cut) *
> #*********************************************************************
> 5 = etaj ! max rap for the jets
> -1 = etab ! max rap for the b
> 2.5 = 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 = etajmin ! min rap for the jets
> 0 = etabmin ! min rap for the b
> 0 = etaamin ! min rap for the photons
> 0 = etalmin ! main rap for the charged leptons
> #*********************************************************************
> # Minimum and maximum DeltaR distance *
> #*********************************************************************
> 0.4 = drjj ! min distance between jets
> 0 = drbb ! min distance between b's
> 0.4 = drll ! min distance between leptons
> 0.4 = draa ! min distance between gammas
> 0 = drbj ! min distance between b and jet
> 0.4 = draj ! min distance between gamma and jet
> 0.4 = drjl ! min distance between jet and lepton
> 0 = drab ! min distance between gamma and b
> 0 = drbl ! min distance between b and lepton
> 0.4 = dral ! min distance between gamma and lepton
> -1 = drjjmax ! max distance between jets
> -1 = drbbmax ! max distance between b's
> -1 = drllmax ! max distance between leptons
> -1 = draamax ! max distance between gammas
> -1 = drbjmax ! max distance between b and jet
> -1 = drajmax ! max distance between gamma and jet
> -1 = drjlmax ! max distance between jet and lepton
> -1 = drabmax ! max distance between gamma and b
> -1 = drblmax ! max distance between b and lepton
> -1 = 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 = mmbb ! min invariant mass of a b pair
> 0 = mmaa ! min invariant mass of gamma gamma pair
> 0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
> -1 = mmjjmax ! max invariant mass of a jet pair
> -1 = mmbbmax ! max invariant mass of a b pair
> -1 = mmaamax ! max invariant mass of gamma gamma pair
> -1 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair
> #*********************************************************************
> # Minimum and maximum invariant mass for all letpons *
> #*********************************************************************
> 0 = mmnl ! min invariant mass for all letpons (l+- and vl)
> -1 = mmnlmax ! max invariant mass for all letpons (l+- and vl)
> #*********************************************************************
> # Minimum and maximum pt for 4-momenta sum of leptons *
> #*********************************************************************
> 0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
> -1 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)
> #*********************************************************************
> # Inclusive cuts *
> #*********************************************************************
> 0 = xptj ! minimum pt for at least one jet
> 0 = xptb ! minimum pt for at least one b
> 0 = xpta ! minimum pt for at least one photon
> 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 = ptj2min ! minimum pt for the second jet in pt
> 0 = ptj3min ! minimum pt for the third jet in pt
> 0 = ptj4min ! minimum pt for the fourth jet in pt
> -1 = ptj1max ! maximum pt for the leading jet in pt
> -1 = ptj2max ! maximum pt for the second jet in pt
> -1 = ptj3max ! maximum pt for the third jet in pt
> -1 = 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 = ptl1min ! minimum pt for the leading lepton in pt
> 0 = ptl2min ! minimum pt for the second lepton in pt
> 0 = ptl3min ! minimum pt for the third lepton in pt
> 0 = ptl4min ! minimum pt for the fourth lepton in pt
> -1 = ptl1max ! maximum pt for the leading lepton in pt
> -1 = ptl2max ! maximum pt for the second lepton in pt
> -1 = ptl3max ! maximum pt for the third lepton in pt
> -1 = ptl4max ! maximum pt for the fourth lepton in pt
> #*********************************************************************
> # Control the Ht(k)=Sum of k leading jets *
> #*********************************************************************
> 0 = htjmin ! minimum jet HT=Sum(jet pt)
> -1 = htjmax ! maximum jet HT=Sum(jet pt)
> 0 = ihtmin !inclusive Ht for all partons (including b)
> -1 = ihtmax !inclusive Ht for all partons (including b)
> 0 = ht2min ! minimum Ht for the two leading jets
> 0 = ht3min ! minimum Ht for the three leading jets
> 0 = ht4min ! minimum Ht for the four leading jets
> -1 = ht2max ! maximum Ht for the two leading jets
> -1 = ht3max ! maximum Ht for the three leading jets
> -1 = 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 = 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 = xetamin ! minimum rapidity for two jets in the WBF case
> 0 = deltaeta ! minimum rapidity for two jets in the WBF case
> #*********************************************************************
> # KT DURHAM CUT *
> #*********************************************************************
> -1 = ktdurham
> 0.4 = dparameter
> #*********************************************************************
> # maximal pdg code for quark to be considered as a light jet *
> # (otherwise b cuts are applied) *
> #*********************************************************************
> 4 = maxjetflavor ! Maximum jet pdg code
> #*********************************************************************
> # Jet measure cuts *
> #*********************************************************************
> 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! *
> #*********************************************************************
> F = 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
> </MGRunCard>
> <slha>
> ######################################################################
> ## 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 DIM6
> ###################################
> Block dim6
> 1 0.000000e+00 # CWWWL2
> 2 1.000000e+00 # CWL2
> 3 1.000000e+00 # CBL2
> 4 0.000000e+00 # CPWWWL2
> 5 0.000000e+00 # CPWL2
> 6 0.000000e+00 # CphidL2
> 7 0.000000e+00 # CphiWL2
> 8 0.000000e+00 # CphiBL2
>
> ###################################
> ## INFORMATION FOR MASS
> ###################################
> Block mass
> 4 1.250000e+00 # MC
> 5 4.200000e+00 # MB
> 6 1.740000e+02 # MT
> 13 1.057000e-01 # MM
> 15 1.777000e+00 # MTA
> 23 9.118820e+01 # MZ
> 25 1.250000e+02 # MH
> 9000006 1.250000e+02 # MP
> ## 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
> 11 0.000000 # e- : 0.0
> 12 0.000000 # ve : 0.0
> 14 0.000000 # vm : 0.0
> 16 0.000000 # vt : 0.0
> 21 0.000000 # g : 0.0
> 22 0.000000 # a : 0.0
> 24 79.824360 # w+ : cmath.sqrt(MZ__exp__2/2. + cmath.sqrt(MZ__exp__4/4. - (aEW*cmath.pi*MZ__exp__2)/(Gf*sqrt__2)))
>
> ###################################
> ## INFORMATION FOR SMINPUTS
> ###################################
> Block sminputs
> 1 1.325049e+02 # aEWM1
> 2 1.166390e-05 # Gf
> 3 1.178000e-01 # aS
>
> ###################################
> ## INFORMATION FOR WOLFENSTEIN
> ###################################
> Block wolfenstein
> 1 0.000000e+00 # lamWS
> 2 0.000000e+00 # AWS
> 3 0.000000e+00 # rhoWS
> 4 0.000000e+00 # etaWS
>
> ###################################
> ## INFORMATION FOR YUKAWA
> ###################################
> Block yukawa
> 4 1.250000e+00 # ymc
> 5 4.200000e+00 # ymb
> 6 1.740000e+02 # ymt
> 13 1.057000e-01 # ymm
> 15 1.777000e+00 # ymtau
>
> ###################################
> ## INFORMATION FOR DECAY
> ###################################
> DECAY 6 1.523000e+00 # WT
> DECAY 15 2.270000e-12 # WTau
> DECAY 23 2.443000e+00 # WZ
> DECAY 24 2.049000e+00 # WW
> DECAY 25 4.143000e-03 # WH
> DECAY 9000006 4.143000e-03 # WH1
> ## 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 16 0.000000 # vt : 0.0
> DECAY 21 0.000000 # g : 0.0
> DECAY 22 0.000000 # a : 0.0
> #===========================================================
> # QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
> #===========================================================
>
> Block QNUMBERS 9000006 # h1
> 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)
> </slha>
> </header>
> </LesHouchesEvents>
>
> ==============================================================================================
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------
> [THIS IS FROM <vertices.py>. ]
> V_12 = Vertex(name = 'V_12',
> particles = [ P.a, P.Z, P.H, P.H ],
> color = [ '1' ],
> lorentz = [ L.VVSS1, L.VVSS5, L.VVSS6 ],
> couplings = {(0,1):C.GC_82,(0,0):C.GC_83,(0,2):C.GC_84})
>
>
>
> [THIS IS FROM <lorentz.py>.]
>
> VVSS1 = Lorentz(name = 'VVSS1',
> spins = [ 3, 3, 1, 1 ],
> structure = 'Epsilon(1,2,-1,-2)*P(-2,1)*P(-1,3) + Epsilon(1,2,-1,-2)*P(-2,1)*P(-1,4)')
> VVSS5 = Lorentz(name = 'VVSS5',
> spins = [ 3, 3, 1, 1 ],
> structure = 'P(1,2)*P(2,1) - P(-1,1)*P(-1,2)*Metric(1,2)')
> VVSS6 = Lorentz(name = 'VVSS6',
> spins = [ 3, 3, 1, 1 ],
> structure = 'P(1,3)*P(2,1) + P(1,4)*P(2,1) - P(-1,1)*P(-1,3)*Metric(1,2) - P(-1,1)*P(-1,4)*Metric(1,2)')
>
>
> [THIS IS FROM <couplings.py> .]
> GC_82 = Coupling(name = 'GC_82',
> value = '-(CphiWL2*cw*ee**2*complex(0,1))/(500000.*sw) + (CphiBL2*ee**2*complex(0,1)*sw)/(1.e6*cw)',
> order = {'NP':2,'QED':1})
>
> GC_83 = Coupling(name = 'GC_83',
> value = '-(CPWL2*cw*ee**2*complex(0,1))/(2.e6*sw) - (CPWL2*ee**2*complex(0,1)*sw)/(2.e6*cw)',
> order = {'NP':2,'QED':1})
>
> GC_84 = Coupling(name = 'GC_84',
> value = '-(CBL2*cw*ee**2*complex(0,1))/(4.e6*sw) + (cw*CWL2*ee**2*complex(0,1))/(4.e6*sw) - (CBL2*ee**2*complex(0,1)*sw)/(4.e6*cw) + (CWL2*ee**2*complex(0,1)*sw)/(4.e6*cw)',
> order = {'NP':2,'QED':1})
>
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks!
But it does not work. :,-(

Is there no possibility that this problem came from other reason?
and I still wonder about the cut off scale.

Hi,

Indeed that’s not your problem since you actually only have the four point diagram.

By running your example (not sure that I put the same cut but this is irrelevant) and looking at the log:
I see:

  Couplings of EWdim6-full
  ---------------------------------

        GC_82 = 0.00000E+00 0.00000E+00
        GC_83 = -0.00000E+00 -0.00000E+00
        GC_84 = 0.00000E+00 0.00000E+00

So your three coupling are estimated to zero.

As you quote you have the following formula:

[THIS IS FROM <couplings.py> .]
GC_82 = Coupling(name = 'GC_82',
                value = '-(CphiWL2*cw*ee**2*complex(0,1))/(500000.*sw) + (CphiBL2*ee**2*complex(0,1)*sw)/(1.e6*cw)',
                order = {'NP':2,'QED':1})

GC_83 = Coupling(name = 'GC_83',
                value = '-(CPWL2*cw*ee**2*complex(0,1))/(2.e6*sw) - (CPWL2*ee**2*complex(0,1)*sw)/(2.e6*cw)',
                order = {'NP':2,'QED':1})

GC_84 = Coupling(name = 'GC_84',
                value = '-(CBL2*cw*ee**2*complex(0,1))/(4.e6*sw) + (cw*CWL2*ee**2*complex(0,1))/(4.e6*sw) - (CBL2*ee**2*complex(0,1)*sw)/(4.e6*cw) + (CWL2*ee**2*complex(0,1)*sw)/(4.e6*cw)',
                order = {'NP':2,'QED':1})

and since you choose:
Block dim6
   1 0.000000e+00 # CWWWL2
   2 1.000000e+00 # CWL2
   3 1.000000e+00 # CBL2
   4 0.000000e+00 # CPWWWL2
   5 0.000000e+00 # CPWL2
   6 0.000000e+00 # CphidL2
   7 0.000000e+00 # CphiWL2
   8 0.000000e+00 # CphiBL2

you can see that GC_82 and GC_83 trivially vanish
For GC_84, this is less clear but when you rewrite that expression in a simpler one:
( (cw -sw) *(CWL2-CBL2))* complex(0,1)* ee**2/(4.e6*cw)
it is clear that it is indeed 0.

If you run with
Block dim6
   1 0.000000e+00 # CWWWL2
   2 2.000000e+00 # CWL2
   3 1.000000e+00 # CBL2
   4 0.000000e+00 # CPWWWL2
   5 0.000000e+00 # CPWL2
   6 0.000000e+00 # CphidL2
   7 0.000000e+00 # CphiWL2
   8 0.000000e+00 # CphiBL2

or with
Block dim6
   1 0.000000e+00 # CWWWL2
   2 1.000000e+00 # CWL2
   3 0.000000e+00 # CBL2
   4 0.000000e+00 # CPWWWL2
   5 0.000000e+00 # CPWL2
   6 0.000000e+00 # CphidL2
   7 0.000000e+00 # CphiWL2
   8 0.000000e+00 # CphiBL2

You will see that you have a non zero result (and identical for those two benchmark).

Cheers,

Olivier

On 10 Aug 2015, at 14:12, Soyoung Shim <email address hidden> wrote:

> Question #270192 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/270192
>
> Status: Answered => Open
>
> Soyoung Shim is still having a problem:
> Thanks!
> But it does not work. :,-(
>
>
> Is there no possibility that this problem came from other reason?
> and I still wonder about the cut off scale.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thanks for your quick answer again!

I tried already one by one and with different coefficients of them. Still, it has zero results.

By the way, where can I find the log file?

Or, is it possible that the results are so small that MG says "zero result" ? (because of the cut off lambda)

Hi Soyoung,

When trying to reproduce Olivier's procedure, make sure that the log files you find in the log files of the SubProcesses/G*/ directories indeed show that the couplings and external parameters where set correctly.

PS:

Also, notice that you could assign to each coupling of interest and individual coupling order, i.e.

GC_82 = Coupling(name = 'GC_82',
                value = '-(CphiWL2*cw*ee**2*complex(0,1))/(500000.*sw) + (CphiBL2*ee**2*complex(0,1)*sw)/(1.e6*cw)',
                order = {'NP':2,'QED':1,'GC82Order':1})

(don't forget to add the corresponding coupling order definition 'GC82Order' in the file coupling_orders.py of the UFO model folder, and the to remove the saved files *.pkl in this model before reloading it, for the changes to take effect)

You can then generate the process by specifying the coupling order GC82Order=1 (or even use the constraint at the amplitude level [i.e. GC82Order^2==1] for computing interferences only for example).
This is however a suboptimal way of turning on only a particular interaction (among other things, because it requires you to regenerate the process evert time) but it might be useful to validate what Olivier suggested and which doesn't work for you.

Cheers,

Hi,

Did you use the EWDim6-full?

I'm worry that the restriction remove that coupling. I will check
but with the EWDim6-full, it works for sure since I get non zero result on my laptop.

Cheers,

Olivier

Hi!

oh maybe when converting models, I missed "-full".
In the EWDim6-full it works, but not in the EWDim6.

I wonder why ..... :,-)

Anyway,
Thanks Olivier and Valentin!

Hi,

> oh maybe when converting models, I missed "-full".
> In the EWDim6-full it works, but not in the EWDim6.

> I wonder why ..... :,-)

That’s a problem of the model simplification that are done at the MadGraph level and not at the FeynRules level.
as explained in our paper: arXiv:1106.0522 this is done by removing all coupling which are zero for a test param_card.
In this case the test param_card have both coupling to the same value and therefore the coupling is discarded.
In principle to avoid this problem, we had put another security but this was explicitly disable for this model by the
model builder stating that it was safe (clearly it is not the case).

Cheers,

Olivier

On 11 Aug 2015, at 11:31, Soyoung Shim <email address hidden> wrote:

> Question #270192 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/270192
>
> Status: Answered => Open
>
> Soyoung Shim is still having a problem:
> Hi!
>
> oh maybe when converting models, I missed "-full".
> In the EWDim6-full it works, but not in the EWDim6.
>
> I wonder why ..... :,-)
>
> Anyway,
> Thanks Olivier and Valentin!
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi,

a proper update of the EWdim6 model (and of the customise_model function) have been pushed in the development version of the code.

Cheers,

Olivier
On 11 Aug 2015, at 11:49, Olivier Mattelaer <email address hidden> wrote:

> Hi,
>
>> oh maybe when converting models, I missed "-full".
>> In the EWDim6-full it works, but not in the EWDim6.
>
>> I wonder why ..... :,-)
>
>
> That’s a problem of the model simplification that are done at the MadGraph level and not at the FeynRules level.
> as explained in our paper: arXiv:1106.0522 this is done by removing all coupling which are zero for a test param_card.
> In this case the test param_card have both coupling to the same value and therefore the coupling is discarded.
> In principle to avoid this problem, we had put another security but this was explicitly disable for this model by the
> model builder stating that it was safe (clearly it is not the case).
>
> Cheers,
>
> Olivier
>
>
>
> On 11 Aug 2015, at 11:31, Soyoung Shim <email address hidden> wrote:
>
>> Question #270192 on MadGraph5_aMC@NLO changed:
>> https://answers.launchpad.net/mg5amcnlo/+question/270192
>>
>> Status: Answered => Open
>>
>> Soyoung Shim is still having a problem:
>> Hi!
>>
>> oh maybe when converting models, I missed "-full".
>> In the EWDim6-full it works, but not in the EWDim6.
>>
>> I wonder why ..... :,-)
>>
>> Anyway,
>> Thanks Olivier and Valentin!
>>
>> --
>> You received this question notification because you are an answer
>> contact for MadGraph5_aMC@NLO.
>

Okay.
I will try again with the new version.

I am really grateful to you :D
Best regards,

So Young.

Hi,

I did not reply on your question on the cut off lambda.
We do not have any cut off value in the code. and do not know what is this scale since the input of the model is only c/Lambda**2.

Cheers,

Olivier