I have an issue with the normalization of the fitted function with RooFit. I know that the PDF of the is automatically adjusted to the number of events. So far so good.
The problem is when I fit twice** the same data with the same PDF, it looks like the normalization gets a factor 2 x the number of events (see attachment). Is there a way to get rid of that factor 2 ?
Thanks,
Salva
** Why do I want to fit twice? Well, in the first pass some parameters are fixed, then released for the second pass