MadSpin problem for 1->N process

Asked by Carl Niblaeus on 2018-11-27

Dear MG experts,

I am having trouble using MadSpin in 1->N processes. I want to look at the decay of a single particle into some two body state, and then letting these two particles decay. I am mainly using a modified version of the DMsimp model in the MG model repository with a scalar that couples to fermions with a scalar and a pseudoscalar coupling (but I also have trouble using just the usual SM, see below). For the fermions, I believe the only difference with respect to the DMsimp scalar model in the model repository is that the pseudoscalar coupling is defined without the complex i.

[ Similar SM problem:
I tried to run MadSpin with a similar ordinary SM process to see if the problem was with the UFO model I am using. It seems not, because the following commands give the same problem as for my UFO model:
./bin/mg5_aMC
generate h > t t~
output [OUTDIR]
launch
madspin=ON
set MH=500

where the madspin_card is set to contain the default commands:
set max_weight_ps_point 400
decay t > w+ b, w+ > all all
decay t~ > w- b~, w- > all all
decay w+ > all all
decay w- > all all
decay z > all all
launch

This results in the same compilation error for the map_external2res array as the one printed out below. ]

Is there a bug when using MadSpin for 1 -> N processes? Because it seems that I can get it to work when running e.g. e+e- collisions.

mg5_aMC is run with the following commands:
generate y0 > t t~
output [OUTDIR]
launch
madspin=ON

The madspin card contains here the following commands:
set max_weight_ps_point 400
decay t > w+ b, w+ > e+ ve
decay t~ > w- b~, w- > e- ve~
launch

Below is my debug file for the y0 > t t~ run (where I have replaced my user directory with "[USERDIR]"):

#************************************************************
#* MadGraph5_aMC@NLO/MadEvent *
#* *
#* * * *
#* * * * * *
#* * * * * 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 MadEvent *
#* *
#* run as ./bin/madevent.py filename *
#* *
#************************************************************
generate_events run_01
Traceback (most recent call last):
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1501, in onecmd
    return self.onecmd_orig(line, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1450, in onecmd_orig
    return func(arg, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/madevent_interface.py", line 2469, in do_generate_events
    self.run_generate_events(switch_mode, args)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/common_run_interface.py", line 6801, in new_fct
    original_fct(obj, *args, **opts)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/madevent_interface.py", line 2562, in run_generate_events
    self.exec_cmd('decay_events -from_cards', postcmd=False)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1528, in exec_cmd
    stop = Cmd.onecmd_orig(current_interface, line, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1450, in onecmd_orig
    return func(arg, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/common_run_interface.py", line 3667, in do_decay_events
    madspin_cmd.import_command_file(path)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1643, in import_command_file
    self.exec_cmd(line, precmd=True)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1528, in exec_cmd
    stop = Cmd.onecmd_orig(current_interface, line, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1450, in onecmd_orig
    return func(arg, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/various/misc.py", line 100, in f_with_no_logger
    out = f(self, *args, **opt)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/MadSpin/interface_madspin.py", line 617, in do_launch
    self.options)
  File "[USERDIR]/MG5_aMC_v2_6_3_2/MadSpin/decay.py", line 2062, in __init__
    self.compile()
  File "[USERDIR]/MG5_aMC_v2_6_3_2/MadSpin/decay.py", line 2924, in compile
    self.compile_fortran(self.path_me, mode="full_me")
  File "[USERDIR]/MG5_aMC_v2_6_3_2/MadSpin/decay.py", line 3020, in compile_fortran
    misc.compile(cwd=new_path, mode='fortran')
  File "[USERDIR]/MG5_aMC_v2_6_3_2/madgraph/various/misc.py", line 527, in compile
    raise MadGraph5Error, error_text
MadGraph5Error: A compilation Error occurs when trying to compile [USERDIR]/MG5_aMC_v2_6_3_2/y0tt/full_me/SubProcesses/P1_y0_ttx_t_bwp_wp_epve_tx_bxwm_wm_emvex.
The compilation fails with the following output message:
    gfortran-7 -O -w -fbounds-check -fPIC -ffixed-line-length-132 -c -o driver.o driver.f
    configs_decay.inc:1:12:

           data (map_external2res(i), i=1,4)/1,2,-2 ,6 /
                1
    Error: Data element above array upper bound at (1)
    make: *** [driver.o] Error 1

Please try to fix this compilations issue and retry.
Help might be found at https://answers.launchpad.net/mg5amcnlo.
If you think that this is a bug, you can report this at https://bugs.launchpad.net/mg5amcnlo
                              Run Options
                              -----------
               stdout_level : 20 (user set)

                         MadEvent Options
                         ----------------
     automatic_html_opening : False (user set)
        notification_center : True
          cluster_temp_path : None
             cluster_memory : None (user set)
               cluster_size : 100
              cluster_queue : None
                    nb_core : 4 (user set)
               cluster_time : 4 (user set)
                   run_mode : 2

                      Configuration Options
                      ---------------------
                text_editor : None
         cluster_local_path : None
      cluster_status_update : (600, 30)
               pythia8_path : [USERDIR]/MG5_aMC_v2_6_3_2/HEPTools/pythia8 (user set)
                  hwpp_path : None (user set)
            pythia-pgs_path : None (user set)
                    td_path : None (user set)
               delphes_path : None (user set)
                thepeg_path : None (user set)
               cluster_type : condor
          madanalysis5_path : [USERDIR]/MG5_aMC_v2_6_3_2/HEPTools/madanalysis5/madanalysis5 (user set)
           cluster_nb_retry : 1
                 eps_viewer : None
                web_browser : None
               syscalc_path : None (user set)
           madanalysis_path : None (user set)
                     lhapdf : [USERDIR]/MG5_aMC_v2_6_3_2/HEPTools/lhapdf6/bin/lhapdf-config (user set)
              f2py_compiler : None
                 hepmc_path : None (user set)
         cluster_retry_wait : 300
           fortran_compiler : gfortran-7 (user set)
                auto_update : 7 (user set)
        exrootanalysis_path : None (user set)
                    timeout : 60
               cpp_compiler : None

The following is the run_card and param_card:
<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>
2.6.4
</MGVersion>
<MG5ProcCard>
<![CDATA[
#************************************************************
#* 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 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~
import model sm-full
import model DMann_ff
generate y0 > t t~
output y0tt
]]>
</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
y0 > 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
DMann_ff
# 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 *
# If you want to run Pythia, avoid more than 50k events in a run. *
#*********************************************************************
  10000 = nevents ! Number of unweighted events requested
 21 = 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
# 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
 5 = 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)
 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) *
#*********************************************************************
 0.0 = ptj ! minimum pt for the jets
 0.0 = ptb ! minimum pt for the b
 0.0 = pta ! minimum pt for the photons
 0.0 = 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) *
#*********************************************************************
  -1.0 = 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! *
#*********************************************************************
 0.0 = 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
 -1.0 = 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] *
#***********************************************************************
 0.0 = ktdurham
 0.0 = dparameter
 0.0 = 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'
]]>
</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 CKMBLOCK
###################################
Block ckmblock
    1 2.277360e-01 # cabi

###################################
## INFORMATION FOR DMINPUTS
###################################
Block dminputs
    1 0.000000e+00 # gSd11
    2 0.000000e+00 # gSu11
    3 0.000000e+00 # gSd22
    4 0.000000e+00 # gSu22
    5 0.000000e+00 # gSd33
    6 1.000000e+00 # gSu33
    7 0.000000e+00 # gPd11
    8 0.000000e+00 # gPu11
    9 0.000000e+00 # gPd22
   10 0.000000e+00 # gPu22
   11 0.000000e+00 # gPd33
   12 1.000000e+00 # gPu33
   13 0.000000e+00 # gSe
   14 0.000000e+00 # gPe
   15 0.000000e+00 # gSmm
   16 0.000000e+00 # gPmm
   17 0.000000e+00 # gSta
   18 0.000000e+00 # gPta
   19 0.000000e+00 # gVd11
   20 0.000000e+00 # gVu11
   21 0.000000e+00 # gVd22
   22 0.000000e+00 # gVu22
   23 0.000000e+00 # gVd33
   24 0.000000e+00 # gVu33
   25 0.000000e+00 # gAd11
   26 0.000000e+00 # gAu11
   27 0.000000e+00 # gAd22
   28 0.000000e+00 # gAu22
   29 0.000000e+00 # gAd33
   30 0.000000e+00 # gAu33
   31 0.000000e+00 # gVe
   32 0.000000e+00 # gAe
   33 0.000000e+00 # gVmm
   34 0.000000e+00 # gAmm
   35 0.000000e+00 # gVta
   36 0.000000e+00 # gAta
   37 1.000000e+04 # Lambda

###################################
## 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
  9000006 1.000000e+03 # MY0
  9000007 1.000000e+03 # MY1
## 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.
  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 1.279000e+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 4.070000e-03 # WH
DECAY 9000006 1.000000e+01 # WY0
DECAY 9000007 1.000000e+01 # WY1
## 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
#===========================================================
# QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
#===========================================================

Block QNUMBERS 9000006 # y0
        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 9000007 # y1
        1 0 # 3 times electric charge
        2 3 # 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>
<MGGenerationInfo>
# Number of Events : 10000
# Integrated weight (pb) : 102.92
</MGGenerationInfo>
</header>
</LesHouchesEvents>

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Carl Niblaeus
Solved:
2018-11-28
Last query:
2018-11-28
Last reply:
2018-11-28

Hi,

Indeed MadSpin was designed for 2>N processes.
In this context, the easiest is to not use MadSpin at all and use the decay chain syntax:

generate h > t t~ , (t > w+ b, w+ > all all), (t~ > w- b~, w- > all all)

Cheers,

Olivier

Carl Niblaeus (cnibl) said : #2

Okay, thank you for the info!

What (if any) are the potential differences/downsides in using the decay chain syntax instead of MadSpin? How different is the treatment of the decays? E.g. spin correlation effects are important for me.

Best,
Carl Niblaeus

Hi,

Spin correlation is fully kept with the above syntax as well as off-shell effect (up to a given number times the width like in MadSpin).
The only difference is in the computation of the cross-section (in your case width).
MadSpin would have assume the NWA and therefore just multiply the original cross-section by the branching ratio.

With the decay-chain syntax, we perform the actual integration over the invariant mass (up to the number of times the width).
and therefore the NWA is not technically use for the computation of the cross-section.
In this context, the NWA is only used in order to justify
1) the diagram filtering (the fact that we neglect a lot of other Feynman diagram leading to the same final state)
2) the cut on the invariant mass (which is needed for the previous point)
In this context, the BR are not used for the computation, but the total width is used.

Cheers,

Olivier

Carl Niblaeus (cnibl) said : #4

Thank you very much for the explanation!

A last question, which I forgot to ask in my previous message:

Is there any difference between writing:

generate h > ta+ ta-, (ta+ > w+ vt~, w+ > e+ ve), (ta- > w- vt, w- > e- ve~)

and

generate h > ta+ ta-, (ta+ > vt~ e+ ve), (ta- > vt e- ve~)

i.e. is the Fermi 3 body decay treated in some special way or are the two syntaxes equivalent (i.e. the second syntax just an alias for the first one)? Looking at the diagrams in the second case, it seems like it is indeed the same as the first since the W:s show up in the decay diagrams.

(I took the taus here as an example instead of tops since I am actually more interested in taus, but I guess it is similar for top decays.)

Hi,

They are a HUGE difference.

In the first case, you ask the W to be onshell. (up to 15 times to width --number that you can decide to change--) so that syntax is likely to return 0.

In the second case, you do not force the W to be onshell and therefore integrate over the full allowed mass range for it.

In the case, of the top quark both syntax are equivalent since you are dominated by the onshell contribution, wich is not the case for tau decay.

Cheers,

Olivier

PS: Note that MadSpin is not working with three body decay in its normal mode --even for cross-section computation--)

Carl Niblaeus (cnibl) said : #6

Ah, that's very good to know. Then probably the 3-body syntax is the way to go for me. Thanks!