Decay chain of Higgs pair with MadSpin

Hi,

Since the Higgs is a spin0, they are no interest to use spinmode on onshell for the HIggs. (expect slowing down your code.)
So please keep the mode to none.

Cheers,

Olivier

> On 30 Apr 2019, at 17:22, Peter Meiring <email address hidden> wrote:
>
> New question #680566 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/680566
>
> Dear MadGraph experts,
>
> To produce gg>hh at NLO I am using the model from arXiv:1401.7340.
>
> After the Higgs pairs are generated I would like one Higgs decaying to b b~ and one Higgs decaying to W+ W-, which both decay leptonically.
>
> So far, I have used MadSpin to do the decays of the Higgs pair:
>
> import model SMEFT_UFO pathtoSMEFT_UFO/restrict_no_b_mass.dat --bypass_nocheck
> set spinmode none
> decay h > b b~
> decay h > w+ w- > l v l v
> launch
>
> Since I set spinmode to "none" there are no spin-correlation effects. I do, however, want to have the correct spin-correlations for the leptons. If I change spinmode to "onshell", I get an error: KeyError : ((21, 21), (25, 25))
> The run_28_tag_1_debug.log is shown below.
>
> Could you please let me know if I'm doing the correct thing to decay the Higgs pair? Am I using the correct commands and what does the error mean?
>
> Looking forward to your response!
> Kind regards,
>
> Peter Meiring
>
>
>
>
>
> #************************************************************
> #* MadGraph5_aMC@NLO *
> #* *
> #* * * *
> #* * * * * *
> #* * * * * 5 * * * * *
> #* * * * * *
> #* * * *
> #* *
> #* *
> #* VERSION 5.2.6.4 20xx-xx-xx *
> #* *
> #* The MadGraph5_aMC@NLO Development Team - Find us at *
> #* https://server06.fynu.ucl.ac.be/projects/madgraph *
> #* and *
> #* http://amcatnlo.cern.ch *
> #* *
> #************************************************************
> #* *
> #* Command File for aMCatNLO *
> #* *
> #* run as ./bin/aMCatNLO.py filename *
> #* *
> #************************************************************
> decay_events run_28
> decay_events run_28
> Traceback (most recent call last):
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/gghhnlo/bin/internal/extended_cmd.py", line 1501, in onecmd
> return self.onecmd_orig(line, **opt)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/gghhnlo/bin/internal/extended_cmd.py", line 1450, in onecmd_orig
> return func(arg, **opt)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/gghhnlo/bin/internal/common_run_interface.py", line 3667, in do_decay_events
> madspin_cmd.import_command_file(path)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/madgraph/interface/extended_cmd.py", line 1643, in import_command_file
> self.exec_cmd(line, precmd=True)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/madgraph/interface/extended_cmd.py", line 1528, in exec_cmd
> stop = Cmd.onecmd_orig(current_interface, line, **opt)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/madgraph/interface/extended_cmd.py", line 1450, in onecmd_orig
> return func(arg, **opt)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/madgraph/various/misc.py", line 100, in f_with_no_logger
> out = f(self, *args, **opt)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/MadSpin/interface_madspin.py", line 576, in do_launch
> return self.run_onshell(line)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/MadSpin/interface_madspin.py", line 1422, in run_onshell
> maxwgt = self.get_maxwgt_for_onshell(orig_lhe, evt_decayfile)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/MadSpin/interface_madspin.py", line 1561, in get_maxwgt_for_onshell
> _, wgt = self.get_onshell_evt_and_wgt(base_event, decays)
> File "/afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/MadSpin/interface_madspin.py", line 1593, in get_onshell_evt_and_wgt
> info = self.generate_all.all_me[tag]
> KeyError: ((21, 21), (25, 25))
> Value of current Options:
> text_editor : None
> notification_center : True
> pjfry : None
> cluster_local_path : None
> cluster_status_update : (600, 30)
> hepmc_path : None
> pythia-pgs_path : None
> thepeg_path : None
> madanalysis5_path : None
> OLP : MadLoop
> applgrid : applgrid-config
> run_mode : 2
> cluster_temp_path : None
> cluster_queue : None
> madanalysis_path : None
> lhapdf : lhapdf-config
> stdout_level : None
> f2py_compiler : None
> ninja : /afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/HEPTools/lib
> automatic_html_opening : True
> cluster_retry_wait : 300
> exrootanalysis_path : None
> timeout : 60
> nb_core : 10
> fortran_compiler : None
> collier : /afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/HEPTools/lib
> pythia8_path : /afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/HEPTools/pythia8
> hwpp_path : None
> golem : None
> td_path : None
> delphes_path : /afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/Delphes
> auto_update : 7
> cluster_type : condor
> eps_viewer : None
> web_browser : None
> cluster_size : 100
> cluster_memory : None
> amcfast : amcfast-config
> output_dependencies : external
> cluster_time : None
> mg5amc_py8_interface_path : /afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4/HEPTools/MG5aMC_PY8_interface
> cluster_nb_retry : 1
> mg5_path : /afs/cern.ch/work/p/pmeiring/private/ATLAS/MG5_aMC_v2_6_4
> syscalc_path : None
> cpp_compiler : None
> #************************************************************
> #* MadGraph5_aMC@NLO *
> #* *
> #* * * *
> #* * * * * *
> #* * * * * 5 * * * * *
> #* * * * * *
> #* * * *
> #* *
> #* *
> #* VERSION 2.6.4 2018-11-09 *
> #* *
> #* 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~
> define l = l+ l-
> define v = vl vl~
> import model SMEFT_UFO-no_b_mass
> define p = 21 2 4 1 3 -2 -4 -1 -3 5 -5
> define j = p
> generate p p > H H [QCD]
> output gghhnlo
> ######################################################################
> ## 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
> 6 1.730000e+02 # MT
> 15 1.777000e+00 # MTA
> 23 9.118760e+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 0.000000 # d : 0.0
> 2 0.000000 # u : 0.0
> 3 0.000000 # s : 0.0
> 4 0.000000 # c : 0.0
> 5 0.000000 # b : 0.0
> 11 0.000000 # e- : 0.0
> 12 0.000000 # ve : 0.0
> 13 0.000000 # mu- : 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)))
> 9000002 91.187600 # ghz : MZ
> 9000003 79.824360 # ghwp : MW
> 9000004 79.824360 # ghwm : MW
> 250 91.187600 # g0 : MZ
> 251 79.824360 # g+ : MW
>
> ###################################
> ## 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
> 6 1.730000e+02 # ymt
> 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 5.753088e-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 0.000000 # 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 15 0.000000 # ta- : 0.0
> DECAY 16 0.000000 # vt : 0.0
> DECAY 21 0.000000 # g : 0.0
> DECAY 22 0.000000 # a : 0.0
> DECAY 9000002 2.495200 # ghz : WZ
> DECAY 9000003 2.085000 # ghwp : WW
> DECAY 9000004 2.085000 # ghwm : WW
> DECAY 250 2.495200 # g0 : WZ
> DECAY 251 2.085000 # g+ : WW
> #===========================================================
> # QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
> #===========================================================
>
> Block QNUMBERS 9000001 # gha
> 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 9000002 # ghz
> 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 9000003 # ghwp
> 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 9000004 # ghwm
> 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 9000005 # ghg
> 1 0 # 3 times electric charge
> 2 1 # number of spin states (2S+1)
> 3 8 # colour rep (1: singlet, 3: triplet, 8: octet)
> 4 1 # Particle/Antiparticle distinction (0=own anti)
> Block QNUMBERS 250 # g0
> 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 251 # g+
> 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)
> #***********************************************************************
> # MadGraph5_aMC@NLO *
> # *
> # run_card.dat aMC@NLO *
> # *
> # This file is used to set the parameters of the run. *
> # *
> # Some notation/conventions: *
> # *
> # Lines starting with a hash (#) 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. *
> # *
> # To display additional parameter, you can use the command: *
> # update to_full *
> #***********************************************************************
> #
> #*******************
> # Running parameters
> #*******************
> #
> #***********************************************************************
> # Tag name for the run (one word) *
> #***********************************************************************
> tag_1 = run_tag ! name of the run
> #***********************************************************************
> # Number of LHE events (and their normalization) and the required *
> # (relative) accuracy on the Xsec. *
> # These values are ignored for fixed order runs *
> #***********************************************************************
> 10000 = nevents ! Number of unweighted events requested
> -1.0 = req_acc ! Required accuracy (-1=auto determined from nevents)
> -1 = nevt_job! Max number of events per job in event generation.
> ! (-1= no split).
> #***********************************************************************
> # Normalize the weights of LHE events such that they sum or average to *
> # the total cross section *
> #***********************************************************************
> average = event_norm ! valid settings: average, sum, bias
> #***********************************************************************
> # Number of points per itegration channel (ignored for aMC@NLO runs) *
> #***********************************************************************
> 0.01 = req_acc_FO ! Required accuracy (-1=ignored, and use the
> ! number of points and iter. below)
> # These numbers are ignored except if req_acc_FO is equal to -1
> 5000 = npoints_FO_grid ! number of points to setup grids
> 4 = niters_FO_grid ! number of iter. to setup grids
> 10000 = npoints_FO ! number of points to compute Xsec
> 6 = niters_FO ! number of iter. to compute Xsec
> #***********************************************************************
> # Random number seed *
> #***********************************************************************
> 0 = iseed ! rnd seed (0=assigned automatically=default))
> #***********************************************************************
> # Collider type and energy *
> #***********************************************************************
> 1 = lpp1 ! beam 1 type (0 = no PDF)
> 1 = lpp2 ! beam 2 type (0 = no PDF)
> 6500.0 = ebeam1 ! beam 1 energy in GeV
> 6500.0 = ebeam2 ! beam 2 energy in GeV
> #***********************************************************************
> # PDF choice: this automatically fixes also alpha_s(MZ) and its evol. *
> #***********************************************************************
> nn23nlo = pdlabel ! PDF set
> 244600 = lhaid ! If pdlabel=lhapdf, this is the lhapdf number. Only
> ! numbers for central PDF sets are allowed. Can be a list;
> ! PDF sets beyond the first are included via reweighting.
> #***********************************************************************
> # Include the NLO Monte Carlo subtr. terms for the following parton *
> # shower (HERWIG6 | HERWIGPP | PYTHIA6Q | PYTHIA6PT | PYTHIA8) *
> # WARNING: PYTHIA6PT works only for processes without FSR!!!! *
> #***********************************************************************
> HERWIG6 = parton_shower
> 1.0 = shower_scale_factor ! multiply default shower starting
> ! scale by this factor
> #***********************************************************************
> # Renormalization and factorization scales *
> # (Default functional form for the non-fixed scales is the sum of *
> # the transverse masses divided by two of all final state particles *
> # and partons. This can be changed in SubProcesses/set_scales.f or via *
> # dynamical_scale_choice option) *
> #***********************************************************************
> False = fixed_ren_scale ! if .true. use fixed ren scale
> False = fixed_fac_scale ! if .true. use fixed fac scale
> 91.118 = muR_ref_fixed ! fixed ren reference scale
> 91.118 = muF_ref_fixed ! fixed fact reference scale
> 10 = dynamical_scale_choice ! Choose one (or more) of the predefined
> ! dynamical choices. Can be a list; scale choices beyond the
> ! first are included via reweighting
> 1.0 = muR_over_ref ! ratio of current muR over reference muR
> 1.0 = muF_over_ref ! ratio of current muF over reference muF
> #***********************************************************************
> # Reweight variables for scale dependence and PDF uncertainty *
> #***********************************************************************
> 1.0, 2.0, 0.5 = rw_rscale ! muR factors to be included by reweighting
> 1.0, 2.0, 0.5 = rw_fscale ! muF factors to be included by reweighting
> True = reweight_scale ! Reweight to get scale variation using the
> ! rw_rscale and rw_fscale factors. Should be a list of
> ! booleans of equal length to dynamical_scale_choice to
> ! specify for which choice to include scale dependence.
> False = reweight_PDF ! Reweight to get PDF uncertainty. Should be a
> ! list booleans of equal length to lhaid to specify for
> ! which PDF set to include the uncertainties.
> #***********************************************************************
> # Store reweight information in the LHE file for off-line model- *
> # parameter reweighting at NLO+PS accuracy *
> #***********************************************************************
> True = store_rwgt_info ! Store info for reweighting in LHE file
> #***********************************************************************
> # ickkw parameter: *
> # 0: No merging *
> # 3: FxFx Merging - WARNING! Applies merging only at the hard-event *
> # level. After showering an MLM-type merging should be applied as *
> # well. See http://amcatnlo.cern.ch/FxFx_merging.htm for details. *
> # 4: UNLOPS merging (with pythia8 only). No interface from within *
> # MG5_aMC available, but available in Pythia8. *
> # -1: NNLL+NLO jet-veto computation. See arxiv:1412.8408 [hep-ph]. *
> #***********************************************************************
> 0 = ickkw
> #***********************************************************************
> #
> #***********************************************************************
> # BW cutoff (M+/-bwcutoff*Gamma). Determines which resonances are *
> # written in the LHE event file *
> #***********************************************************************
> 15.0 = bwcutoff
> #***********************************************************************
> # Cuts on the jets. Jet clustering is performed by FastJet. *
> # - When matching to a parton shower, these generation cuts should be *
> # considerably softer than the analysis cuts. *
> # - More specific cuts can be specified in SubProcesses/cuts.f *
> #***********************************************************************
> 1.0 = jetalgo ! FastJet jet algorithm (1=kT, 0=C/A, -1=anti-kT)
> 0.7 = jetradius ! The radius parameter for the jet algorithm
> 10.0 = ptj ! Min jet transverse momentum
> -1.0 = etaj ! Max jet abs(pseudo-rap) (a value .lt.0 means no cut)
> #***********************************************************************
> # Cuts on the charged leptons (e+, e-, mu+, mu-, tau+ and tau-) *
> # More specific cuts can be specified in SubProcesses/cuts.f *
> #***********************************************************************
> 7.0 = ptl ! Min lepton transverse momentum
> 2.8 = etal ! Max lepton abs(pseudo-rap) (a value .lt.0 means no cut)
> 0.0 = drll ! Min distance between opposite sign lepton pairs
> 0.0 = drll_sf ! Min distance between opp. sign same-flavor lepton pairs
> 0.0 = mll ! Min inv. mass of all opposite sign lepton pairs
> 30.0 = mll_sf ! Min inv. mass of all opp. sign same-flavor lepton pairs
> #***********************************************************************
> # Photon-isolation cuts, according to hep-ph/9801442. When ptgmin=0, *
> # all the other parameters are ignored. *
> # More specific cuts can be specified in SubProcesses/cuts.f *
> #***********************************************************************
> 20.0 = ptgmin ! Min photon transverse momentum
> -1.0 = etagamma ! Max photon abs(pseudo-rap)
> 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)
> #***********************************************************************
> # Cuts associated to MASSIVE particles identified by their PDG codes. *
> # All cuts are applied to both particles and anti-particles, so use *
> # POSITIVE PDG CODES only. Example of the syntax is {6 : 100} or *
> # {6:100, 25:200} for multiple particles *
> #***********************************************************************
> {} = pt_min_pdg ! Min pT for a massive particle
> {} = pt_max_pdg ! Max pT for a massive particle
> {} = mxx_min_pdg ! inv. mass for any pair of (anti)particles
> #***********************************************************************
> # For aMCfast+APPLGRID use in PDF fitting (http://amcfast.hepforge.org)*
> #***********************************************************************
> 0 = iappl ! aMCfast switch (0=OFF, 1=prepare grids, 2=fill grids)
> #***********************************************************************
>
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,

Thank you very much for you quick reply!

I asked this question, since I'm trying to compare my own generated samples with ATLAS samples, which have used the same model for the generation of the Higgs-pair. ATLAS used Herwig7 to do the decays and showering, whereas I used MadSpin for the decays and Herwig6 for the showering.

We have seen some difference in kinematics; For example, the pt of the charged leptons is higher (~10 GeV roughly speaking) and the DeltaPhi between the charged leptons is a bit lower.

Since the cuts at generation (like minimum lepton pt) are the same, we expected the observed differences are coming from how we decay the Higgs pair, more specifically the spin-correlations.

As you suggested, spinmode "none" works fine, but does this mean that the W's from h>WW can also have f.e. a non-zero sum of spins? And is there then also no spin-correlation in the leptons and the W's?

We have also been in contact with Stefano Frixione about this same question. In fact, he did suggest spinmode "onshell" when decaying H>WW. I think it would be nice to compare both spinmode "none" and spinmode "onshell" to look for kinematic differences. However, the error above appears and it crashes. Do you think it is possible to get spinmode "onshell" working?

Thanks again, your help is highly appreciated!
Cheers,

Peter Meiring

Hi,

> As you suggested, spinmode "none" works fine, but does this mean that
> the W's from h>WW can also have f.e. a non-zero sum of spins? And is
> there then also no spin-correlation in the leptons and the W's?

The H > 4 lepton have full spin-correlation in the spin-mode "none" case.

To be precise, the spin-mode "none" do the following:
1) it generates N events for g g > h h. (with standard MG5aMC method)
2) it generates N events for h > b b~ (with standard MG5aMC method)
3) it generates N events for h > W+ W- > l v l v (with standard MG5aMC method)
4) it takes each events of the g g > h h sample and glue to them (i.e. boost the 4-momenta)
one of the event of the two other sample such that the Higgs 4-momenta match.

The mode onshell, does actually the same. but has in top of that an accept/rejection method
to correct for the spin-correlation of the Higgs propagators.
This is given by |M_full|^2/|M_prod^2/ |M_dec1|^2/ |M_dec2|^2

Since the decaying particle are spin 0. this ratio should always be a constant and therefore the onshell mode
should keep all event (i.e. behaves like the none mode).
I would actually consider any deviation between the two method as a bug.

> We have also been in contact with Stefano Frixione about this same
> question. In fact, he did suggest spinmode "onshell" when decaying H>WW.
> I think it would be nice to compare both spinmode "none" and spinmode
> "onshell" to look for kinematic differences.

Interesting maybe but only to spot error/bug in the onshell method.

> Do you think it is possible to get spinmode
> "onshell" working?

In this context, I would not care at all, yes it would be nice to have it working, but this has very low priority.

Cheers,

Olivier

> On 1 May 2019, at 13:33, Peter Meiring <email address hidden> wrote:
>
> Question #680566 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/680566
>
> Status: Answered => Open
>
> Peter Meiring is still having a problem:
> Hi Olivier,
>
> Thank you very much for you quick reply!
>
> I asked this question, since I'm trying to compare my own generated
> samples with ATLAS samples, which have used the same model for the
> generation of the Higgs-pair. ATLAS used Herwig7 to do the decays and
> showering, whereas I used MadSpin for the decays and Herwig6 for the
> showering.
>
> We have seen some difference in kinematics; For example, the pt of the
> charged leptons is higher (~10 GeV roughly speaking) and the DeltaPhi
> between the charged leptons is a bit lower.
>
> Since the cuts at generation (like minimum lepton pt) are the same, we
> expected the observed differences are coming from how we decay the Higgs
> pair, more specifically the spin-correlations.
>
> As you suggested, spinmode "none" works fine, but does this mean that
> the W's from h>WW can also have f.e. a non-zero sum of spins? And is
> there then also no spin-correlation in the leptons and the W's?
>
> We have also been in contact with Stefano Frixione about this same
> question. In fact, he did suggest spinmode "onshell" when decaying H>WW.
> I think it would be nice to compare both spinmode "none" and spinmode
> "onshell" to look for kinematic differences. However, the error above
> appears and it crashes. Do you think it is possible to get spinmode
> "onshell" working?
>
> Thanks again, your help is highly appreciated!
> Cheers,
>
> Peter Meiring
>
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> contact for MadGraph5_aMC@NLO.

Thank you very much! That solved my question.