I just want to try to follow some Tevatron papers and calculate the Mellin Convolution in a simplified way. I guess it would be faster than RooFFTConvPdf here:
The convolution “mConv” in [color=brown][ Exp(t|k*tau) fConv Gau(st)] mConv H(k) [/color] is calculated in this way:
where h(k_i) is the i-th bin content, w_i is bin width. The problem is that RooClassFactory::makePdf can only deal with the RooRealVar variables. I also tried to read the source codes of RooDecay. It is not very complicated, and there is a RooResolutionModel. I should admit that I am not familiar with C++ and still haven’t understood the framework there.
I think the format of my Pdf could be something like:
kHist is just the histogram of k factor, decayModel is a RooDecay Pdf. In this case we could also change the Resolution models and so on.
But I don’t know how to write
so that I don’t need to take care of the normalization of [color=brown][Exp(t|k_i*tau) fConv Gau(st)][/color], or just reuse some codes in RooFit so that it can deal with different RooResolutionModel as well.
Could you please give me some hints how to do that (or point me some examples)?
Thanks a lot.