[Rivet] Normalisation of histograms in MC_Z* analyses

[Frank Siegert]

Hi all,

> when running some of the MC_Z* analyses, I observed differences in the way
> histograms are normalised. E.g. in the analysis MC_ZJETS all histograms
> inherited from the MC_JetAnalysis are normalised using  Scale(hist,
> crossSection()/sumOfWeights()) which in my opinion seems to be the correct
> approach. On the contrary, the two histograms Z_jet1_dR and Z_jet1_deta are
> normalised using normalize(hist, crossSection()/picobarn) which can be quite
> misleading in my opinion.

I agree, these histograms should definitely be using scale(hist,
xs/sumOfWeights()) and not normalize. This also used to be the case,
but was changed a while ago:
https://rivet.hepforge.org/trac/changeset/8c96bd39e1f006b308af846dfd2dac361f11aca5#file26

Andy, do you remember why?

> Also, the description of MC_ZJETS (data/anainfo/
> MC_ZJETS.info) is a bit outdated as e.g. the Z mass distribution is not
> available.

Right, that has been moved to the MC_ZINC when the analyses were
split, and I must have forgot to update the descriptions, sorry!

Cheers,
Frank