Hello. I am trying to fit a momentum distribution as a sum of a gaussian plus an exponential. I followed the example multifit.C in the tutorials folder. In the first range I fit an exponential and in the second range a gaussian. Each individual fit looks ok, but the sum of the two is horrible and looks nothing like the individual fits. Any suggestions? I’ve attached the code and the plot that I get. Also, any suggestions on how to reduce the chi^2 once I do get the sum to look ok?

Thank you for your time!

momentum.pdf (15.7 KB)

momentum.cpp (1.5 KB)