Curve Fitting (python)

Hello!

I am extremely new to ROOT, and I have produced a 2d dE/dx histogram, and now I am trying to fit a curve in order to make cuts on the particles. I have tried to find a guide but all the manuals appear to be for the C++ version.

So far I’ve tried to go to the fit panel and entering an equation like this:
y=([0]/(x+[1]))+[2]

However, whenever I press fit, it spits out nonsense values for each of the parameters, and draws a group of red lines somewhere on the histogram. Is there any simple way for me to get an upper and lower bound for the curve in the photo?

Thank you!

In your case, depending on what you want to do, it might be better to use a TCutG.