AddNormFactor - how to constrain it to other parameters?

Roofit and RooStats
1

Hi all,

I have a question regarding AddNormFactor in HistFactory. In my model I have 3 different backgrounds.
I have added a normalisation factor for background1 in the standard way and it is free to vary within a certain range. Now I would like to constrain the normalisation of background 2 to be 1/3 of the normalisation of background1. In Roofit I would do it as RooFormula, but I can not find a way to do this in the HistFatory formalism.
How can I do this?

Thanks!

2

Hi,

I don’t think this is possible directly in the HIstFactory. You would need to edit by hand the created workspace and modify adding the needed relationship between the background normalisations

Lorenzo