Which value of alphaS MG uses?

Hi,

So the value of alphas at MZ used is going to be 0.13
Then it will be run at alphas(mass_alp) which I do not know the value from those printout.
If you look at the detail log, it is going to be printed (we technically print it only for the first event but since your dynamical scale is actually fixed this will do the trick for all events)

Cheers,

Olivier

Dear Olivier, thank you for the answer. However, I cannot find the value of alphas in tag_*_banner.txt:

<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>
3.4.2
</MGVersion>
<MG5ProcCard>
<![CDATA[
#************************************************************
#* MadGraph5_aMC@NLO *
#* *
#* * * *
#* * * * * *
#* * * * * 5 * * * * *
#* * * * * *
#* * * *
#* *
#* *
#* VERSION 3.4.2 2023-01-20 *
#* *
#* 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 group_subprocesses Auto
set ignore_six_quark_processes False
set low_mem_multicore_nlo_generation False
set complex_mass_scheme False
set include_lepton_initiated_processes False
set gauge unitary
set loop_optimized_output True
set loop_color_flows False
set max_npoint_for_channel 0
set default_unset_couplings 99
set max_t_for_channel 99
set zerowidth_tchannel True
set nlo_mixed_expansion True
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 /home/name/Downloads/mg5/models/ALPs-gluon_UFO
generate g g > alp
output alp-prod-1.5-GeV
]]>
</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
g g > alp #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
ALPs-gluon_UFO
# 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 to_full *
#*********************************************************************
#
#*********************************************************************
# 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 *
#*********************************************************************
  400000 = 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=elastic photon of proton,*
# +/-3=PDF of electron/positron beam *
# +/-4=PDF of muon/antimuon beam *
#*********************************************************************
     1 = lpp1 ! beam 1 type
     1 = lpp2 ! beam 2 type
     400.0 = ebeam1 ! beam 1 total energy in GeV
     0.0 = ebeam2 ! beam 2 total energy in GeV
# To see polarised beam options: type "update beam_pol"

#*********************************************************************
# PDF CHOICE: this automatically fixes alpha_s and its evol. *
# pdlabel: lhapdf=LHAPDF (installation needed) [1412.7420] *
# iww=Improved Weizsaecker-Williams Approx.[hep-ph/9310350] *
# eva=Effective W/Z/A Approx. [21yy.zzzzz] *
# none=No PDF, same as lhapdf with lppx=0 *
#*********************************************************************
     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
 4 = 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)
  average = event_norm ! average/sum. Normalization of the weight in the LHEF
# To see MLM/CKKW merging options: type "update MLM" or "update CKKW"

#*********************************************************************
#
#*********************************************************************
# Phase-Space Optimization strategy (basic options)
#*********************************************************************
   0 = nhel ! using helicities importance sampling or not.
                             ! 0: sum over helicity, 1: importance sampling
   2 = sde_strategy ! default integration strategy (hep-ph/2021.00773)
                             ! 1 is old strategy (using amp square)
        ! 2 is new strategy (using only the denominator)
# To see advanced option for Phase-Space optimization: type "update psoptim"
#*********************************************************************
# 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 *
#*******************************
  0.0 = dsqrt_shat ! minimal shat for full process
#
#
#*********************************************************************
# BW cutoff (M+/-bwcutoff*Gamma) ! Define on/off-shell for "$" and decay
#*********************************************************************
  15.0 = bwcutoff ! (M+/-bwcutoff*Gamma)
#*********************************************************************
# Standard Cuts *
#*********************************************************************
# Minimum and maximum pt's (for max, -1 means no cut) *
#*********************************************************************
 {} = 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) *
#*********************************************************************
 {} = 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 *
#*********************************************************************
#*********************************************************************
# Minimum and maximum invariant mass for pairs *
#*********************************************************************
 {} = 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.
#*********************************************************************
# Inclusive cuts *
#*********************************************************************
 0.0 = ptheavy ! minimum pt for at least one heavy final state
#*********************************************************************
# 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 *
#*********************************************************************
   True = 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
]]>
</MGRunCard>
<slha>
######################################################################
## PARAM_CARD AUTOMATICALY GENERATED BY MG5 ####
######################################################################
###################################
## INFORMATION FOR FRBLOCK
###################################
BLOCK FRBLOCK #
      1 1.000000e+00 # ga
###################################
## INFORMATION FOR MASS
###################################
BLOCK MASS #
      5 4.700000e+00 # mb
      6 1.720000e+02 # mt
      15 1.777000e+00 # mta
      23 9.118760e+01 # mz
      25 1.250000e+02 # mh
      12345678 1.500000e+00 # ma
      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 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 1.300000e-01 # as (note that parameter not used if you use a pdf set)
###################################
## INFORMATION FOR YUKAWA
###################################
BLOCK YUKAWA #
      5 4.700000e+00 # ymb
      6 1.720000e+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 4.070000e-03 # wh
DECAY 12345678 1.000000e+00 # wa
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
###################################
## INFORMATION FOR QNUMBERS 12345678
###################################
BLOCK QNUMBERS 12345678 # alp
      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)
</slha>
<MGPythiaCard>
<![CDATA[
!
! It is possible to run this card manually with:
! LD_LIBRARY_PATH=/home/name/Downloads/mg5/HEPTools/lib:$LD_LIBRARY_PATH
 unset PYTHIA8DATA
/home/name/Downloads/mg5/HEPTools/MG5aMC_PY8_interface/MG5aMC_PY8_interface tag_1_pythia8.cmd
!
!
! Pythia8 cmd card automatically generated by MadGraph5_aMC@NLO
! For more information on the use of the MG5aMC / Pythia8 interface, visit
! https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/LOPY8Merging
!
! ==================
! General parameters
! ==================
!
Main:numberOfEvents = -1
!
! -------------------------------------------------------------------
! Specify the HEPMC output of the Pythia8 shower. You can set it to:
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! hepmc.gz : Same as 'hepmc', but also will compress the output file.
! hepmcremove : MG5aMC will automatically remove the file at the end of the run.
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! hepmc@<hepmc_path> :
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! fifo@<fifo_path> :
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! -------------------------------------------------------------------
!
HEPMCoutput:file = tag_1_pythia8_events.hepmc
!
! --------------------------------------------------------------------
! Parameters relevant only when performing MLM merging, which can be
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! 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.
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! 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'
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! used to instruct Pythia to guess the hard process. The guess would mean
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! 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
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! 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
! 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
JetMatching:etaJetMax=1.0000000000e+03
! Specify one must read inputs from the MadGraph banner.
JetMatching:setMad=off
!
! ====================
! Subrun definitions
! ====================
!
LHEFInputs:nSubruns=1
Main:subrun=0
!
! Definition of subrun 0
!
Beams:LHEF=unweighted_events.lhe.gz
]]>
</MGPythiaCard>
<MGGenerationInfo>
# Number of Events : 400000
# Integrated weight (pb) : 44758000000.0
</MGGenerationInfo>
</header>
<init>
2212 2212 4.000000e+02 9.380000e-01 0 0 247000 247000 -4 1
4.475800e+10 3.180500e+06 4.475800e+10 1
<generator name='MadGraph5_aMC@NLO' version='3.4.2'>please cite 1405.0301 </generator>
</init>
</LesHouchesEvents>

Correct that information is not in the banner, it is in the detail log (the one associated to each channel)
You will also have the value of alphas written on the lhef file on the event by event basis.

Cheers,

Olivier

Dear Olivier,

Thanks! Could you please tell me where I may find these logs?

Thanks Oliview!

Thanks Olivier Mattelaer, that solved my question.