Dear experts,
I am attempting the same type of fit described here, where I am using a sum of RooHistPdf templates within a RooRealSumPdf.
It seems that RooRealSumPdf can handle negative coefficient values, but not negative bin content in the histogram templates - the fit breaks down when I introduce templates which are negative in certain bins, whereas it works fine with templates that are positive everywhere.
My histograms parameterise sine and cosine terms in an angular distributions, and can thus be negative in certain regions. I use histograms rather than a RooGenericPdf function in order to model the angular resolution.
Is there any way to fit using histogram templates with negative bin content in ROOT? The sum of all of my histograms is positive everywhere, so my hope was that something like RooRealSumPdf would work.
Cheers,
Donal