## Creating new histograms

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 $\phi$