Is there a way to get the correlation between two variables not stored in a TTree but stemming from two TH1 ? In case it is not, is it possible to make a TTree out of a TH1 already saved ie not on the fly like here
if you have two separate one-dimensional histograms, the information about the correlation of the variable is lost.
If you mean reconstructing a TTree from an histogram entry-by-entry, no it’s not possible.