First bin incorrect in HistFactory workspaces

[StephanH]

The explanation is here:

Extracting histograms from HistFactory generated RooWorkspace

I figured out what was happening. I didn’t cut on channelCat, and because each channel has it’s own observable, when one observable is plotted, the events from the other channels all end up in one bin. I’m not sure why this one bin isn’t an over / underflow bin. root [4] d->get(0)->Print("V"); d->weight(); 1) RooCategory:: channelCat = resolved_4b_2015(idx = 0) 2) RooRealVar:: obs_x_resolved_4b_2015 = 266.667 3) RooRealVar:: obs_x_resolved_4b_2016 = 266.667 4) RooRealVar:: …