Hello, I have a very similar question to the one posted here: https://answers.launchpad.net/mg5amcnlo/+question/707138 I would like to specify 2.9 syntax in my process, but cannot use "set acknowledged_v3.1_syntax True" because the madgraph configuration file in my environment is not writable. ie, I get: Read-only file system: '/cvmfs/atlas.cern.ch/repo/sw/software/23.6/sw/lcg/releases/MCGenerators/madgraph5amc/3.5.3.atlas5-e6f9c/x86_64-centos7-gcc11-opt/input/mg5_configuration.txt' The answer is most likely no, but is there a way to use 2.9 syntax without altering mg5_configuration.txt? I have also tried using commands like this: generate p p > t~ b wp+ NP<= 1 aEW<=0 [QCD] And my events are generated correctly, but Madspin fails stating: MadGraph5Error : Decay processes cannot specify squared orders constraints. In the post above, they asked if "aS/aEW are constraints on QCD^2/QED^2 (?)", and I am wondering about this too. This new physics process runs with Madgraph 2.9 with just "generate p p > t~ b wp+ [QCD]", where it also correctly runs in Madspin as well. Any information would greatly be appreciated. Thank you! Jason _________________________________________________________________________________________________________ Here is some more info from the log: generating the production square matrix element generate p p > t~ b wp+ NP<=1 aEW<=0 --no_warning=duplicate;define pert_QCD = -4 -3 -2 -1 1 2 3 4 21;add process p p > t~ b wp+ pert_QCD NP<=1 aEW<=0 --no_warning=duplicate; Done 2.527 generating the full matrix element squared (with decay) generate p p > t~ b wp+ NP<=1 aEW<=0, (wp+ > b~ t , ( t > b w+ , w+ > all all ) QCD=99), (t~ > b~ w- , w- > all all QCD=99) --no_warning=duplicate;define pert_QCD = -4 -3 -2 -1 1 2 3 4 21;add process p p > t~ b wp+ pert_QCD NP<=1 aEW<=0, (wp+ > b~ t , ( t > b w+ , w+ > all all ) QCD=99), (t~ > b~ w- , w- > all all QCD=99) --no_warning=duplicate; And this is my Madspin configuration: #************************************************************ #* MadSpin * #* * #* P. Artoisenet, R. Frederix, R. Rietkerk, O. Mattelaer * #* * #* Part of the MadGraph5_aMC@NLO Framework: * #* The MadGraph5_aMC@NLO Development Team - Find us at * #* https://server06.fynu.ucl.ac.be/projects/madgraph * #* * #************************************************************ #Some options (uncomment to apply) # # set seed 1 # set Nevents_for_max_weight 75 # number of events for the estimate of the max. weight # set BW_cut 15 # cut on how far the particle can be off-shell set max_weight_ps_point 400 # number of PS to estimate the maximum for each event # set seed 1325 # specify the decay for the final state particles decay wp+ > t b~, (t > w+ b, w+ > all all) decay wp- > t~ b, (t~ > w- b~, w- > all all) 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 # running the actual code launch

When	Who	Action	New State
2024-04-11	Olivier Mattelaer	Answer	Answered
2024-04-11	Jason Gombas	Confirm	Solved
2024-04-11	Zachary Marshall	Comment	Solved
2024-04-15	meeloun education	Comment	Solved

MadGraph5_aMC@NLO

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