Dear MadGraph experts, I'm looking into the process e+ e- > l+ l- j j / h , as a background to single-Higgs production via ZBF. At the cuts.f level, I require the product of the leptons' rapidities to be negative in order to ensure that they are in opposite regions of the detector. To make sure that as much PS is covered as possible, at the run_card level I set the minimum pT of the final-state objects (leptons and jets) to be 0.5 GeV, and their \eta < 5.0. A further cut on the invariant mass of the dilepton system is required for several centre-of-mass energies, namely \sqrt{s} = {1, 3} TeV => mmll = {300, 1000} GeV respectively. The hard_survey flag is set to 1. With this minimal set of cuts, I find that MadGraph either gets stuck refining events, or simply fails to reach target by a huge margin. After playing a while, I noticed that hardening the pT cut of the jets solves the issue (say, for 1 TeV I had to set ptj = 20 GeV, and to 60 GeV for 3 TeV), but on doing so I'm skewing the samples and hence introducing unwanted bias to the analysis. Please find below the banner of the latter case. NOTE: This is not the case for other backgrounds, such as lla, where the looser cuts (pta = 0.5 GeV) give no trouble. Any ideas of why such a loose cut might be troublesome for MadGraph, and any tips on how to overcome this situation without skewing the samples? Best wishes, Oscar. ----------

#2.7.3 l l myj myj / h ALL=99 set automatic_html_opening False output eejj1000_10 ]]> #********************************************************************* # 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 e+ e- > l l myj myj / h #Process # Be carefull the coupling are here in MG5 convention ALL=99 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 HEFT_UFO_Real-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 ###################################################################### ## PARAM_CARD AUTOMATICALY GENERATED BY MG5 #### ###################################################################### ################################### ## INFORMATION FOR CKMBLOCK ################################### BLOCK CKMBLOCK # 1 2.277360e-01 # cabi ################################### ## INFORMATION FOR MASS ################################### BLOCK MASS # 1 5.040000e-03 # md 2 2.550000e-03 # mu 3 1.010000e-01 # ms 4 1.270000e+00 # mc 5 4.700000e+00 # mb 6 1.720000e+02 # mt 11 5.110000e-04 # me 13 1.056600e-01 # mmu 15 1.777000e+00 # mta 23 9.118760e+01 # mz 25 1.250000e+02 # mh 12 0.000000e+00 # ve : 0.0 14 0.000000e+00 # vm : 0.0 16 0.000000e+00 # vt : 0.0 21 0.000000e+00 # g : 0.0 22 0.000000e+00 # a : 0.0 24 7.982436e+01 # w+ : cmath.sqrt(mz__exp__2/2. + cmath.sqrt(mz__exp__4/4. - (aew*cmath.pi*mz__exp__2)/(gf*sqrt__2))) ################################### ## INFORMATION FOR SMINPUTS ################################### BLOCK SMINPUTS # 1 1.279000e+02 # aewm1 2 1.166370e-05 # gf 3 1.184000e-01 # as ################################### ## INFORMATION FOR YUKAWA ################################### BLOCK YUKAWA # 1 5.040000e-03 # ymdo 2 2.550000e-03 # ymup 3 1.010000e-01 # yms 4 1.270000e+00 # ymc 5 4.700000e+00 # ymb 6 1.720000e+02 # ymt 11 5.110000e-04 # yme 13 1.056600e-01 # ymm 15 1.777000e+00 # ymtau ################################### ## INFORMATION FOR DECAY ################################### DECAY 6 1.508336e+00 # wt DECAY 23 2.495200e+00 # wz DECAY 24 2.085000e+00 # ww DECAY 25 4.088000e-03 # wh 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 directory ! /dev/null : to turn off the HEPMC output. ! : to select where the HEPMC file must written. It will ! therefore not be placed in the run_ directory. The ! specified path, if not absolute, will be relative to ! the Event/run_ directory of the process output. ! fifo : to have MG5aMC setup the piping of the PY8 output to ! analysis tools such as MadAnalysis5. ! fifo@ : ! Same as 'fifo', but selecting a custom path to create the ! fifo pipe. (useful to select a mounted drive that supports ! fifo). Note that the fifo file extension *must* be '.hepmc.fifo'. ! ------------------------------------------------------------------- ! HEPMCoutput:file = eejj1000_10_pythia8_events.hepmc ! ! -------------------------------------------------------------------- ! Parameters relevant only when performing MLM merging, which can be ! turned on by setting ickkw to '1' in the run_card and chosing a ! positive value for the parameter xqcut. ! For details, see section 'Jet Matching' on the left-hand menu of ! http://home.thep.lu.se/~torbjorn/pythia81html/Welcome.html ! -------------------------------------------------------------------- ! If equal to -1.0, MadGraph5_aMC@NLO will set it automatically based ! on the parameter 'xqcut' of the run_card.dat ! The following parameter was forced to be commented out by MG5aMC. ! JetMatching:qCut = -1.0 ! Use default kt-MLM to match parton level jets to those produced by the ! shower. But the other Shower-kt scheme is available too with this option. ! The following parameter was forced to be commented out by MG5aMC. ! JetMatching:doShowerKt = off ! A value of -1 means that it is automatically guessed by MadGraph. ! It is however always safer to explicitly set it. ! The following parameter was forced to be commented out by MG5aMC. ! JetMatching:nJetMax = -1 ! ! -------------------------------------------------------------------- ! Parameters relevant only when performing CKKW-L merging, which can ! be turned on by setting the parameter 'ptlund' *or* 'ktdurham' to ! a positive value. ! For details, see section 'CKKW-L Merging' on the left-hand menu of ! http://home.thep.lu.se/~torbjorn/pythia81html/Welcome.html ! -------------------------------------------------------------------- ! Central merging scale values you want to be used. ! If equal to -1.0, then MadGraph5_aMC@NLO will set this automatically ! based on the parameter 'ktdurham' of the run_card.dat ! The following parameter was forced to be commented out by MG5aMC. ! Merging:TMS = -1.0 ! This must be set manually, according to Pythia8 directives. ! An example of possible value is 'pp>LEPTONS,NEUTRINOS' ! Alternatively, from Pythia v8.223 onwards, the value 'guess' can be ! used to instruct Pythia to guess the hard process. The guess would mean ! that all particles apart from light partons will be considered as a part ! of the hard process. This guess is prone to errors if the desired hard ! process is complicated (i.e. contains light partons). The user should ! then be wary of suspicious error messages in the Pythia log file. ! The following parameter was forced to be commented out by MG5aMC. ! Merging:Process = ! A value of -1 means that it is automatically guessed by MadGraph. ! It is however always safer to explicitly set it. ! The following parameter was forced to be commented out by MG5aMC. ! Merging:nJetMax = -1 ! ! For all merging schemes, decide whehter you want the merging scale ! variation computed for only the central weights or all other ! PDF and scale variation weights as well SysCalc:fullCutVariation = off ! ! ========================== ! User customized parameters ! ========================== ! ! By default, Pythia8 generates multi-parton interaction events. This is ! often irrelevant for phenomenology and very slow. You can turn this ! feature off by uncommenting the line below if so desired. !partonlevel:mpi = off ! ! Additional technical parameters set by MG5_aMC. ! ! Tell Pythia8 that an LHEF input is used. Beams:frameType=4 ! Specify one must read inputs from the MadGraph banner. JetMatching:setMad=off JetMatching:etaJetMax=1.0000000000e+03 ! 1.0 corresponds to HEPMC weight given in [mb]. We choose here the [pb] normalization. HEPMCoutput:scaling=1.0000000000e+09 ! Be more forgiving with momentum mismatches. Check:epTolErr=1.0000000000e-02 ! ! ==================== ! Subrun definitions ! ==================== ! LHEFInputs:nSubruns=1 Main:subrun=0 ! ! Definition of subrun 0 ! Beams:LHEF=unweighted_events.lhe.gz ]]> # Number of Events : 150000 # Integrated weight (pb) : 0.247347721564

-11 11 5.000000e+02 5.000000e+02 0 0 247000 247000 -4 1 2.473477e-01 1.844448e-04 2.473477e-01 1 please cite 1405.0301

MadGraph5_aMC@NLO

History of question #696785