How to write Delta function convoluted with the double gaussian in Roofit

sanjeeda · April 10, 2021, 5:01am

Dear Expert,

I am trying to do a 2D fit of below two distributions

using a delta function convoluted with the Double gaussian.

Here’s the complete folder that I am using : 2D_fit.zip (236.5 KB) but it’s not working.

Can you help me with this?

Regards
Chanchal

jonas · April 10, 2021, 9:24am

The convolution you want to do is possible in general. The problem in your code seems to me that you defined the Gaussian for x=pi0_ErrM and the resolution model and convolution for x=pi0_M_prefit.

If you want to a convolution, you got to define the inputs for the same x axis. Maybe you meant to use pi0_ErrM for everything up to the convolution? And then pi0_M_prefit only for the RooJohnson in the other dimension?

Let me know if this goes in the right direction and if you have further questions!

Cheers,
Jonas

sanjeeda · April 12, 2021, 4:51am

Dear @jonas,

Thank you very much. Now the code is working.

system · April 26, 2021, 4:52am

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