TSPlot problem

Dear Experts,

Firstly I would like to say that I studied the TSPlot tutorial thoroughly but it didn’t help.
I am writing to ask for your advice regarding the TSPlot class. I am not able to make it work - the output weighted discriminating variable histograms look the same ( even the same scale) for signal and background, no matter how I tune the parameters for pdfs. i also get negative number of events after running the code. I attach a piece of code that you can use to reproduce the problem and a root file with a tree containing the discriminating variable “FinalMass” and a control variable (just have to specify the input and output path).

ReaderSPlotOutput_mumu.root (101 KB)
Splotting.txt (2.09 KB)