Additional histograms can be created easily in VBFNLO by modifying the file utilities/histograms.F.

• In the subroutine InitHistograms create a new histogram with the following command:

          call CreateHist(HIST_ID, "title",nobins,xmin,xmax)   
   

  • HIST_ID = integer identification of histogram (make sure to use a different number for each histogram)
  • title = title of histogram, will be used as plot title – e.g. dS/dmjj : dijet mass
  • nobins = number of histogram bins
  • xmin = lower bound of histogram
  • xmax = upper bound of histogram
• In the subroutine HistogramEvent
  • calculate your desired distribution value - e.g. dijet mass mjj
  • Fill the new histogram using the command:

            call FillHist(HIST_ID, value, dw, NLO)   
     

    • HIST_ID = integer identification of histogram, same number as in CreateHist
    • value = value of your distribution variable (e.g. mjj)
    • dw = the variable dw (this is already calculated by the code – it is the weight*cross section)
    • NLO = the variable NLO (this is already filled by the code – flag determining the order of the calculation)

Information about the final state particles is stored in the arrays jets, leptons, invisible (neutrinos) and photons. The entries are as follows

• jets(i,j) : information about the jets is stored here, entries are $p_{T}$-ordered
  • j = jet number
  • i = 0-3 = 4-momentum
  • i = 4 = mass
  • i = 5 = transverse momentum $p_{T}$
  • i = 6 = rapidity $y$
  • i = 7 = azimuthal angle $\phi$
• leptons(i,j) : information about the charged leptons is stored here
  • j = lepton number
  • i = 0-3 = 4-momentum
  • i = 4 = mass (all leptons are treated as massless, i.e. this entry is always equal to zero)
  • i = 5 = transverse momentum $p_{T}$
  • i = 6 = rapidity $y$
  • i = 7 = azimuthal angle $\phi$
  • i = 8 = lepton ID (i.e. PDG particle number)
• invisible(i,j) : information about the invisible particles (i.e. neutrinos) is stored here
  • j = neutrino number
  • i = 0-3 = 4-momentum
  • i = 4 = mass
  • i = 5 = transverse momentum $p_{T}$
  • i = 6 = rapidity $y$
  • i = 7 = azimuthal angle $\phi$
  • i = 8 = neutrino ID (i.e. PDG particle number)
• photons(i,j) : information about the photons is stored here
  • j = photon number
  • i = 0-3 = 4-momentum
  • i = 4 = mass
  • i = 5 = transverse momentum $p_{T}$
  • i = 6 = rapidity $y$
  • i = 7 = azimuthal angle $\phi$