#************************************************************************* # Reweight Module * # Matrix-Element reweighting at LO/NLO * # Mattelaer Olivier arxiv:xxxx.xxxx * #************************************************************************* # # Note: # 1) the value of alpha_s will be used from the event so the value in # the param_card is not taken into account. # 2) It is (in general) dangerous/wrong to change parameters by a large # amount, if this changes the shape of the matrix elements a lot. # (For example, changing a particle's mass by much more than its # width leads to very inaccurate result). In such a case, separate # event generation runs are needed. # #************************************************************************ # ENTER YOUR COMMANDS BELOW. #************************************************************************ change mode NLO # Define type of Reweighting. For LO sample this command # has no effect since only "LO" mode is allowed. launch # SPECIFY A PATH OR USE THE SET COMMAND LIKE THIS: # set sminputs 1 130 # modify 1/alpha_EW #************************************************************************ # Manual: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/Reweight #************************************************************************ # # Example of (standard) code for the computation of two weights: # # launch ! tag to start the computation of the first weight # set BLOCKNAME ID VALUE ! rule to modify the current param_card # set BLOCKNAME ID VALUE ! rule to modify the current param_card # launch ! start to compute a second weight # /home/Cards/param_card_2.dat ! you can also enter a path to a valid card # # Note: The command to specify the parameter are AFTER the associated "launch" # # Possible options: # You can enter one of the following lines to customize the reweighting # procedure. These need to be given before the 'launch' command. # # change model NAME : use another model for the matrix-elements to reweight # with. In this case you need to provide the path to a correct # param_card for the new model; you cannot modify the original one # with the 'set' command. # change process DEF [--add]: change the process by which you reweight. # The initial and final state particles of the new process should # be exactly identical to the ones in the original process. # change helicity False: perform the reweighting by helicity summed # matrix-elements even if the events have been written with a # single helicity state. # change mode XXX: change the type of reweighting performed. # allowed values: LO, NLO, LO+NLO # - This command has no effect for reweighting an .lhe event file with LO accuracy. # In that case LO mode is always used (whatever entry is set). # - When the .lhe file reweighted is at NLO accuracy, then all modes are allowed. # * "LO" is an approximate leading order method # * "NLO" is the NLO accurate method # * "LO+NLO" runs both # - "NLO" and "LO+NLO" modes requires 'store_rwgt_info' equals True (run_card.dat) # If the reweighting is done at generation level this parameter will # automatically be set on True. #************************************************************************