Dear experts, I hope you are all well and safe.

I have a naive question, I am filling THnSparse histograms with some weight, for example:

Int_t bins4D[4] = {100, 48, 64, 500};

Double_t xmin4D[4] = {0.0, -2.4, -3.2, 0.};

Double_t xmax4D[4] = {10.0, 2.4, 3.2, 500.};

Double_t weight=50; //related with trigger reweighing

THnSparseD *histo = new THnSparseD(“histo”,“histo”,4,bins4D,xmin4D,xmax4D);

histo->Sumw2();

…In the loop…

Double_t x4D[3]={pT,eta,phi,multiplicity};

histo->Fill(x4D, weight);

I know that the weight is working fine, because of the multiplicity distribution.

However as the weight is applied and > 0, my error bars are smaller than the expected.

I checked here in TH1::Fill|(x,w) - https://root.cern.ch/doc/master/classTH1.html#a498de8e0804e75fc75e62dc14a3bb62d

and is mentioned:

If the weight is not equal to 1, the storage of the sum of squares of weights is automatically triggered and the sum of the squares of weights is incremented by 𝑤2 in the bin corresponding to x

Is there any way to not take this weight into account in the error bars?

Thank you in advance,

Dener