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 $\phi$