QCD background measurement

[katilp]

(from #7 - @slaurila )

Currently the QCD background is estimated using a same-sign control-region, and then normalized to the opposite-sign signal region with an ad-hoc transfer factor of 0.80. As suggested by Stefan, this transfer factor could and should be measured from a separate control region, as done for the actual Run-1 result. However, having separate control regions for different purposes can make the code a bit messy, so it might be better to have a separate script to determine this transfer factor.

[stwunsch]

I've here a very simple script, which uses the antiiso region on ntuple level to estimate the extrapolation factor: https://gist.github.com/stwunsch/8b184f88266d7ac196195a94adace7f1
I get 0.92 ;) However, no fit, no uncertainties, but probably we're fine with that?