[PWGHF] Fix normalisation in macro for FONLL+PYTHIA prediction for non-prompt Hc (AliceO2Group#16628)

Co-authored-by: ALICE Action Bot <alibuild@cern.ch>

Author: fgrosa

PWGHF/Macros/computeFonllPlusPythiaPredictions.C

@@ -316,12 +316,12 @@ void computeFonllPlusPythiaPredictions(int nDecays, int seed, std::string inFile
 
   std::array<float, 3> normCrossSec{};
   for (auto iFonll{0}; iFonll < 3; ++iFonll) {
-    normCrossSec[iFonll] = hFonllBhad[iFonll]->Integral();
+    normCrossSec[iFonll] = hFonllBhad[iFonll]->Integral(1, hFonllBhad[iFonll]->GetNbinsX() + 1, "width");
     for (auto iChad{0}; iChad < NCharmHadrons; ++iChad) {
       hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][NBeautyHadrons][iFonll] = reinterpret_cast<TH1D*>(hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][0][iFonll]->Clone(Form("hFonllNonPrompt%s%s", charmHadNames[iChad].data(), namesFonll[iFonll].data())));
       hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][NBeautyHadrons][iFonll]->Reset();
       for (auto iBHad{0}; iBHad < NBeautyHadrons; ++iBHad) {
-        hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][iBHad][iFonll]->Scale(normCrossSec[iFonll] / nDecays);
+        hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][iBHad][iFonll]->Scale(normCrossSec[iFonll] / nDecays, "width");
         hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][NBeautyHadrons][iFonll]->Add(hFonllPythiaNonPromptChad[charmHadPdgs[iChad]][iBHad][iFonll]);
       }
     }