add POWHEG jet configuration and ini file, pp 13.6 TeV (#2178)

* add POWHEG jet configuration and ini file, pp 13.6 TeV

* select dijet POWHEG process

Author: jaimenorman

MC/config/PWGGAJE/external/powheg/powheg_jetjet_13600.input

@@ -0,0 +1,90 @@
+numevts 10        ! number of events to be generated
+ih1  1               ! hadron 1 (1 for protons, -1 for antiprotons)
+ih2  1               ! hadron 2 (1 for protons, -1 for antiprotons)
+ebeam1 6800d0    ! energy of beam 1
+ebeam2 6800d0    ! energy of beam 2
+
+bornktmin 1d0       ! (default 0d0) Generation cut: minimum kt in underlying Born
+bornsuppfact 120d0   ! (default 0d0) Mass parameter for Born suppression factor.
+                     ! If < 0 suppfact = 1.
+
+
+! To be set only if using internal (mlm) pdfs
+! 131 cteq6m
+! ndns1 131            ! pdf set for hadron 1 (mlm numbering)
+! ndns2 131            ! pdf set for hadron 2 (mlm numbering)
+
+! To be set only if using LHA pdfs
+! 10050 cteq6m
+! 10550 cteq66
+! 13100 CT14nlo
+! 14400 CT18nlo
+lhans1  14400      ! pdf set for hadron 1 (LHA numbering)
+lhans2  14400      ! pdf set for hadron 2 (LHA numbering)
+
+! To be set only if using different pdf sets for the two incoming hadrons
+# QCDLambda5  0.25    ! for not equal pdf sets
+
+#renscfact  1d0      ! (default 1d0) ren scale factor: muren  = muref * renscfact
+#facscfact  1d0      ! (default 1d0) fac scale factor: mufact = muref * facscfact
+
+! Parameters to allow or not the use of stored data
+use-old-grid    1    ! If 1 use old grid if file pwggrids.dat is present (<> 1 regenerate)
+use-old-ubound  1    ! If 1 use norm of upper bounding function stored
+                     ! in pwgubound.dat, if present; <> 1 regenerate
+
+! A typical call uses 1/1400 seconds (1400 calls per second)
+ncall1 20000         ! No. calls for the construction of the importance sampling grid
+itmx1 5              ! No. iterations for grid: total 100000 calls ~ 70 seconds
+ncall2 20000         ! No. calls for the computation of the upper bounding
+                     ! envelope for the generation of radiation
+itmx2 5              ! No. iterations for the above
+
+! Notice: the total number of calls is ncall2*itmx2*foldcsi*foldy*foldphi
+! these folding numbers yield a negative fraction of 0.5% with bornktmin=10 GeV.
+! With these settings: ncall2*itmx2*foldcsi*foldy*foldphi=5M, 60 minutes
+foldcsi 5            ! No. folds on csi integration
+foldy   5            ! No. folds on  y  integration
+foldphi 2            ! No. folds on phi integration
+
+nubound 500000       ! No. calls to set up the upper bounding norms for radiation.
+                     ! This is performed using only the Born cross section (fast)
+
+! OPTIONAL PARAMETERS
+
+withnegweights 0     ! (default 0). If 1 use negative weights.
+#bornonly 1          ! (default 0). If 1 compute underlying Born using LO
+                     ! cross section only.
+
+#ptsqmin    0.8      ! (default 0.8 GeV) minimum pt for generation of radiation
+#charmthr   1.5      ! (default 1.5 GeV) charm treshold for gluon splitting
+#bottomthr  5.0      ! (default 5.0 GeV) bottom treshold for gluon splitting
+#testplots  1        ! (default 0, do not) do NLO and PWHG distributions
+#charmthrpdf  1.5    ! (default 1.5 GeV) pdf charm treshold
+#bottomthrpdf 5.0    ! (default 5.0 GeV) pdf bottom treshold
+
+#xupbound 2d0        ! increase upper bound for radiation generation
+
+#iseed    5421       ! Start the random number generator with seed iseed
+#rand1     0         ! skipping  rand2*100000000+rand1 numbers (see RM48
+#rand2     0         ! short writeup in CERNLIB).
+#manyseeds 1         ! Used to perform multiple runs with different random
+                     ! seeds in the same directory.
+                     ! If set to 1, the program asks for an integer j;
+                     ! The file pwgseeds.dat at line j is read, and the
+                     ! integer at line j is used to initialize the random
+                     ! sequence for the generation of the event.
+                     ! The event file is called pwgevents-'j'.lhe
+
+doublefsr 1          ! Default 0; if 1 use new mechanism to generate regions
+                     ! such that the emitted harder than the
+                     ! emitter in FSR is suppressed. If doublefsr=0 this is
+                     ! only the case for emitted gluons (old behaviour). If
+                     ! 1 it is also applied to emitted quarks.
+                     ! If set, it strongly reduces spikes on showered output.
+
+
+
+par_diexp 4         ! default is 2. With 4 there is a stronger separation
+par_dijexp 4        ! of regions, it may help to reduce spikes when generating
+par_2gsupp 4        ! weighted events.

MC/config/PWGGAJE/ini/GeneratorPythia8POWHEG_jetjet_13600.ini

@@ -0,0 +1,10 @@
+### The external generator derives from GeneratorPythia8.
+## The generator allows to run Pythia8 with POWHEG
+## The option '3' which is given to getGeneratorJEPythia8POWHEG selects the pwhg_main_dijet process
+#---> GeneratorPythia8POWHEG
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGGAJE/external/generator/generator_pythia8_powheg.C
+funcName=getGeneratorJEPythia8POWHEG("${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGGAJE/external/powheg/powheg_jetjet_13600.input","",3)
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGGAJE/pythia8/generator/pythia8_powheg.cfg