issue with auto-width (four body decay)

[Olivier Mattelaer]

Dear MadGraph experts,
  I obtain the following error message when requesting Auto calculation of widths:
set zerowidth_tchannel True" with error:
ValueError : -24 is not in list
  I am using version 2.9.5 of MadGraph5_aMC@NLO, with model GM_UFO_nlo.
The process is:
generate p p > H5pp j j  [QCD]
and the param_card is given below. On a first pass, the error is:
  Pass to numerical integration for computing the widths:
  Command "launch auto " interrupted in sub-command:
  "set zerowidth_tchannel True" with error:
  ValueError : -24 is not in list
But the widths are calculated and the param_card updated. With a relaunch, there is no problem.
With version 3.2.0, the error is different:
  set nlo_mixed_expansion True with error: ValueError : -24 is not in list

 Thank you very much in advance for your help.
  Georges

Here is the param_card used as input:
######################################################################
## PARAM_CARD GENERATED BY GMCALC ##
######################################################################
## ##
## Width set on Auto will be computed following the ##
## information present in the decay.py files of the ##
## model. By default, this is only 1->2 decay modes. ##
## ##
######################################################################

###################################
## INFORMATION FOR LOOP
###################################
Block loop
    1 0.803850E+02 # MU_R

###################################
## INFORMATION FOR MASS
###################################
Block mass
    6 0.172500E+03 # MT
   13 0.105658E+00 # MM
   15 0.177682E+01 # MTA
   23 0.911876E+02 # MZ
   24 0.803850E+02 # MW
   25 0.125000E+03 # Mh
  252 0.630390E+03 # H
  253 0.628094E+03 # H3p
  255 0.600000E+03 # H5pp
  254 0.628094E+03 # H3z
  256 0.600000E+03 # H5p
  257 0.600000E+03 # H5z
## Dependent parameters, given by model restrictions. ##
## MG5 ignores these values but they are important ##
## for interfacing the output of MG5 to external ##
## programs such as Pythia. ##
    1 0.000000E+00 # MD
    2 0.000000E+00 # MU
    3 0.000000E+00 # MS
    4 0.000000E+00 # MC
    5 0.000000E+00 # MB
   11 0.000000E+00 # Me
   12 0.000000E+00 # ve
   14 0.000000E+00 # vm
   16 0.000000E+00 # vt
   21 0.000000E+00 # g
   22 0.000000E+00 # a

###################################
## INFORMATION FOR POTENTIALPARAM
###################################
Block potentialparam
    1 0.240000E+00 # lam2
    2 -.100000E+00 # lam3
    3 0.200000E+00 # lam4
    4 -.870587E+00 # lam5
    5 0.120874E+04 # M1coeff
    6 0.201456E+03 # M2coeff

###################################
## INFORMATION FOR SMINPUTS
###################################
Block sminputs
    1 0.132233E+03 # aEWM1
    2 0.116638E-04 # Gf
    3 0.118000E+00 # aS

###################################
## INFORMATION FOR VEV
###################################
Block vev
    1 0.577350E+00 # tanth

###################################
## INFORMATION FOR YUKAWA
###################################
Block yukawa
    1 0.504000E-02 # ymdo
    2 0.255000E-02 # ymup
    3 0.000000E+00 # yms
    4 0.164384E+01 # ymc
    5 0.457936E+01 # ymb
    6 0.172500E+03 # ymt
   11 0.511000E-03 # yme
   13 0.105658E+00 # ymm
   15 0.177682E+01 # ymtau

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 0.150834E+01 # WT
DECAY 23 0.249520E+01 # WZ
DECAY 24 0.208500E+01 # WW
DECAY 25 Auto # Wh
DECAY 252 Auto # Wh__2
DECAY 253 Auto # WH3p
DECAY 254 Auto # WH3z
DECAY 255 Auto # WH5pp
DECAY 256 Auto # WH5p
DECAY 257 Auto # WH5z
## Dependent parameters, given by model restrictions. ##
## MG5 ignores these values but they are important ##
## for interfacing the output of MG5 to external ##
## programs such as Pythia. ##
DECAY 1 0.000000E+00 # d
DECAY 2 0.000000E+00 # u
DECAY 3 0.000000E+00 # s
DECAY 4 0.000000E+00 # c
DECAY 5 0.000000E+00 # b
DECAY 11 0.000000E+00 # e-
DECAY 12 0.000000E+00 # ve
DECAY 13 0.000000E+00 # mu-
DECAY 14 0.000000E+00 # vm
DECAY 15 0.000000E+00 # ta-
DECAY 16 0.000000E+00 # vt
DECAY 21 0.000000E+00 # g
DECAY 22 0.000000E+00 # a
#===========================================================
# QUANTUM NUMBERS OF NEW STATE(S) (NON SM PDG CODE)
#===========================================================

Block QNUMBERS 252 # H
        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 253 # H3p
        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 254 # H3z
        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 255 # H5++
        1 6 # 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 256 # H5p
        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 257 # H5z
        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)

[Olivier Mattelaer (olivier-mattelaer)]

More information:

reproduced with
"""
import model GM_UFO_nlo
generate p p > t t~
output
launch
./param_gm.dat
"""

 log:

INFO: Get two body decay from FeynRules formula
Results written to /Users/omattelaer/Documents/workspace/2.9.4/PROC_GM_UFO_nlo_0/Cards/param_card.dat
INFO: get decay diagram for H5p
Vertexlist of this model has not been searched.Automatically run the model.find_vertexlist()
Found 4 stable particles
INFO: get decay diagram for H5z
INFO: current estimated error: 0.00701944466552034 go to 4-body decay:
100 / 186: 2s
INFO: get decay diagram for h
INFO: get decay diagram for H
INFO: current estimated error: 0.0030256673796129428 go to 4-body decay:
100 / 130: 2s
INFO: stop to 4.0 body-decay. approximate error: 0.03930356032486867
INFO: get decay diagram for H3p
INFO: current estimated error: 0.017673593843884807 go to 4-body decay:
100 / 125: 2s
INFO: stop to 4.0 body-decay. approximate error: 0.05464673152646782
INFO: get decay diagram for H3z
INFO: current estimated error: 0.007626109856174273 go to 4-body decay:
100 / 172: 2s
INFO: stop to 4.0 body-decay. approximate error: 0.011205467368340301
INFO: get decay diagram for H5pp
INFO: current estimated error: 0.053955490775377236 go to 4-body decay:
Pass to numerical integration for computing the widths:
INFO: More info in temporary files:
    /Users/omattelaer/Documents/workspace/2.9.4/tmpykt29_fh/temp_decay/index.html
Command "generate_events run_01" interrupted in sub-command:
"set zerowidth_tchannel True" with error:
ValueError : -24 is not in list
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in 'MG5_debug'.
Please attach this file to your report.

[Olivier Mattelaer (olivier-mattelaer)]

A first patch (not optimal in term of memory management but functional is the following):

=== modified file 'mg5decay/decay_objects.py'
--- mg5decay/decay_objects.py 2022-02-05 20:06:43 +0000
+++ mg5decay/decay_objects.py 2022-02-10 20:17:32 +0000
@@ -3420,11 +3421,10 @@
         for new_numbers in itertools.permutations(numbers):

             mapping_id = dict([(o,n) for o,n in zip(numbers, new_numbers) if o!=n])
-
             if not mapping_id:
                 out.append(self)
                 continue
- channel = copy.copy(self)
+ channel = copy.deepcopy(self)
             channel['vertices'] = base_objects.VertexList()
                     # (real) DiagramTag
             channel['tag'] = []

[Olivier Mattelaer (olivier-mattelaer)]

This patch/revision should fix the issue in a more proper way.
https://bazaar.launchpad.net/~maddevelopers/mg5amcnlo/LTS_dev/revision/380

[Georges Azuelos (georges-azuelos)]

Thanks a lot, Oliver, for the fix.