PhotonFlux PDF results in "nan" event

Hi,

This should have been fixed a while ago, could you try the latest version of the code or at least the long term stable version (2.9.3).

Those version also allows for lpp=4 for supporting the muon case.

Cheers,

Olivier

> On 7 May 2021, at 21:35, Han Qin <email address hidden> wrote:
>
> New question #696969 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/696969
>
> Dear MadGraph experts,
>
> I am studying VBF processes at lepton colliders, e.g. a a > t t~ where the photons are from the emissions of beam electron/muon. I use the built-in photon pdf by setting lpp1 and lpp2 in run_card to 3. If the beam is muon, I just change the mass parameter in PhotonFlux.f to muon mass.
>
> However, I noticed when the beam energy is large, for example 5 TeV + 5 TeV, there are many events that the z component and the energy of particles' four-momentum is "nan" or "inf". I don't know why this happens. Could you please help me fix this issue?
>
> Thank you very much!
>
> The madgraph version I am using is 2.6.7. I also attach one example of "nan" event and my banner below.
>
> <event>
> 4 1 +1.6018000e-02 1.74897600e+02 7.54677100e-03 1.17283500e-01
> 22 -1 0 0 0 0 +0.0000000000e+00 +0.0000000000e+00 +nan nan 0.0000000000e+00 0.0000e+00 1.0000e+00
> 22 -1 0 0 0 0 -0.0000000000e+00 -0.0000000000e+00 -inf inf 0.0000000000e+00 0.0000e+00 1.0000e+00
> 6 1 1 2 501 0 +8.0173104874e+00 +2.4410592463e+01 +nan nan 1.7300000000e+02 0.0000e+00 1.0000e+00
> -6 1 1 2 0 501 -8.0173104874e+00 -2.4410592463e+01 -inf inf 1.7300000000e+02 0.0000e+00 1.0000e+00
> </event>
>
>
>
> <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 *
> # *
> # The MadGraph5_aMC@NLO team *
> # *
> #....................................................................*
> # *
> # 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>
> 2.6.7
> </MGVersion>
> <MG5ProcCard>
> <![CDATA[
> #************************************************************
> #* MadGraph5_aMC@NLO *
> #* *
> #* * * *
> #* * * * * *
> #* * * * * 5 * * * * *
> #* * * * * *
> #* * * *
> #* *
> #* *
> #* VERSION 2.6.7 2019-10-16 *
> #* *
> #* 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 default_unset_couplings 99
> set group_subprocesses Auto
> set ignore_six_quark_processes False
> set loop_optimized_output True
> set low_mem_multicore_nlo_generation False
> set loop_color_flows False
> set gauge unitary
> set complex_mass_scheme False
> set max_npoint_for_channel 0
> 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~
> generate a a > t t~
> output sm_aa_ttbar
> ]]>
> </MG5ProcCard>
> <MGProcCard>
> #*********************************************************************
> # MadGraph/MadEvent *
> # http://madgraph.hep.uiuc.edu *
> # *
> # proc_card.dat *
> #*********************************************************************
> # *
> # This Files is generated by MADGRAPH 5 *
> # *
> # WARNING: This Files is generated for MADEVENT (compatibility issue)*
> # This files is NOT a valid MG4 proc_card.dat *
> # Running this in MG4 will NEVER reproduce the result of MG5*
> # *
> #*********************************************************************
> #*********************************************************************
> # Process(es) requested : mg2 input *
> #*********************************************************************
> # Begin PROCESS # This is TAG. Do not modify this line
> a a > t t~ #Process
> # Be carefull the coupling are here in MG5 convention
>
> end_coup # End the couplings input
>
> done # this tells MG there are no more procs
> # End PROCESS # This is TAG. Do not modify this line
> #*********************************************************************
> # Model information *
> #*********************************************************************
> # Begin MODEL # This is TAG. Do not modify this line
> sm
> # End MODEL # This is TAG. Do not modify this line
> #*********************************************************************
> # Start multiparticle definitions *
> #*********************************************************************
> # Begin MULTIPARTICLES # This is TAG. Do not modify this line
>
> # End MULTIPARTICLES # This is TAG. Do not modify this line
> </MGProcCard>
> <MGRunCard>
> <![CDATA[
> #*********************************************************************
> # 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 *
> # *
> # To display more options, you can type the command: *
> # update full_run_card *
> #*********************************************************************
> #
> #*******************
> # 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 *
> #*********************************************************************
> 10000 = nevents ! Number of unweighted events requested
> 30 = 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 *
> #*********************************************************************
> 3 = lpp1 ! beam 1 type
> 3 = lpp2 ! beam 2 type
> 5000.0 = ebeam1 ! beam 1 total energy in GeV
> 5000.0 = ebeam2 ! beam 2 total energy in GeV
> # To see polarised beam options: type "update beam_pol"
> #*********************************************************************
> # 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
> # To see heavy ion options: type "update ion_pdf"
> #*********************************************************************
> # 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 livetime 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
> True = auto_ptj_mjj ! Automatic setting of ptj and mjj if xqcut >0
> ! (turn off for VBF and single top processes)
> 0.0 = 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
> #*********************************************************************
> 15.0 = 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) *
> #*********************************************************************
> 20.0 = ptj ! minimum pt for the jets
> 0.0 = ptb ! minimum pt for the b
> 10.0 = pta ! minimum pt for the photons
> 10.0 = 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})
> #
> # For display option for energy cut in the partonic center of mass frame type 'update ecut'
> #
> #*********************************************************************
> # Maximum and minimum absolute rapidity (for max, -1 means no cut) *
> #*********************************************************************
> 5.0 = etaj ! max rap for the jets
> -1.0 = etab ! max rap for the b
> 2.5 = etaa ! max rap for the photons
> 2.5 = 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 *
> #*********************************************************************
> 0.4 = drjj ! min distance between jets
> 0.0 = drbb ! min distance between b's
> 0.4 = drll ! min distance between leptons
> 0.4 = draa ! min distance between gammas
> 0.0 = 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
> 0.0 = drab ! min distance between gamma and b
> 0.0 = drbl ! min distance between b and lepton
> 0.4 = 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
> {} = 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 *
> #*********************************************************************
> 0.0 = 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
> 0.0 = 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] *
> #***********************************************************************
> -1.0 = 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
> #
> systematics = systematics_program ! none, systematics [python], SysCalc [depreceted, C++]
> ['--mur=0.5,1,2', '--muf=0.5,1,2', '--pdf=errorset'] = systematics_arguments ! see: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/Systematics#Systematicspythonmodule
> # Syscalc is deprecated but to see the associate options type'update syscalc'#*********************************************************************
> # Additional hidden parameters
> #*********************************************************************
> ['--mur=0.5,1,2', '--muf=0.5,1,2', '--pdf=errorset'] = systematics_arguments # Choose the argment to pass to the systematics command. like --mur=0.25,1,4. Look at the help of the systematics function for more details.
> ]]>
> </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 MASS
> ###################################
> Block mass
> 5 4.700000e+00 # MB
> 6 1.730000e+02 # MT
> 15 1.777000e+00 # MTA
> 23 9.118800e+01 # MZ
> 25 1.250000e+02 # MH
> ## Dependent parameters, given by model restrictions.
> ## Those values should be edited following the
> ## analytical expression. MG5 ignores those values
> ## but they are important for interfacing the output of MG5
> ## to external program such as Pythia.
> 1 0.000000e+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 8.041900e+01 # 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 1.325070e+02 # aEWM1
> 2 1.166390e-05 # Gf
> 3 1.180000e-01 # aS
>
> ###################################
> ## INFORMATION FOR YUKAWA
> ###################################
> Block yukawa
> 5 4.700000e+00 # ymb
> 6 1.730000e+02 # ymt
> 15 1.777000e+00 # ymtau
>
> ###################################
> ## INFORMATION FOR DECAY
> ###################################
> DECAY 6 1.491500e+00 # WT
> DECAY 23 2.441404e+00 # WZ
> DECAY 24 2.047600e+00 # WW
> DECAY 25 6.382339e-03 # WH
> ## Dependent parameters, given by model restrictions.
> ## Those values should be edited following the
> ## analytical expression. MG5 ignores those values
> ## but they are important for interfacing the output of MG5
> ## to external program such as Pythia.
> DECAY 1 0.000000e+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
> </slha>
> <MGGenerationInfo>
> # Number of Events : 10000
> # Integrated weight (pb) : 0.016018
> </MGGenerationInfo>
> </header>
> </LesHouchesEvents>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Thank you, Olivier! I tried 2.9.3, it works fine!

Meanwhile, I have a related question. It seems only a fixed factorization scale is allowed for photon emitted from lepton. If I want to use s-hat as factorization scale, is there any way I can do that?

Alright. Thank you, Olivier!

Thanks Olivier Mattelaer, that solved my question.