RooRealVar with arrays and vectors

Roofit and RooStats
1

Dear experts,

I would like to link a RooRealVar to the first element of an array in a TTree.
I tried with:

RooRealVar B0_DTF_PV_JPs_M = new RooRealVar(“B0_DTF_PV_JPs_M[0]”,"M_{B #rightarrow J/#psi K^{}}",5150,6000,“MeV/c^{2}”);
RooDataSet *rdsMCB0_DTF_PV_JPs_M = new RooDataSet(“rdsMCB0_DTF_PV_JPs_M”,“rdsMCB0_DTF_PV_JPs_M”,RooArgSet(*B0_DTF_PV_JPs_M),Import(*tMC));

where the B0_DTF_PV_JPs_M is the array-like TBranch in the TTree, but this is not working.
I saw that there has been a similar discussion in 2010, and at that time this option was not implemented.
Is it still the case? What would you suggest to do?

Thanks for your help,

Federica

2

Hi,

It is correct. I don’t this this is possible. I would suggest you create a reduced tree or you just loop by hand on the tree entries and you fill your RooDataSet. It should be quite simple to do it

Best Regards

Lorenzo

3

Dear Lorenzo,

thanks for your help, this is actually the workaround I used.

Cheers,

Federica