Question: how to read a root file using ROOT?

[Marouane]

Hello everyone,
I start to write my own script to analyse the Z boson decay to double muons using root.
My question is that when I open the browser (using the command new TBrowser
), I see the distributions of muonPx, muonPy and muonPz as Gausian, but when I read the browser (see my code bellow) I find only one bin in each histogram (I do not get the same resulte as in the browser)!!
Please how can I fix this problem? Is there any problem or wrong command?
Thank you

// ------------------------------
// My code
// ------------------------------

//                                                                              
// This code calculate the masste of the Z boson using TTree from               
// its decay to double charged muons \mu{+}\mu{-}                               
//                                                                              
void ctr1()
{

  TFile *input =new TFile("ntuple_array.root","READ");
  //auto hfile = TFile("ntuple_array.root");                                    


  TTree *tree = (TTree*)input->Get("ntupleProducer/tree;1");

  Float_t muonPx, muonPy, muonPz, muonPt;

  tree->SetBranchAddress("muonPx",&muonPx);
  tree->SetBranchAddress("muonPy",&muonPy);
  tree->SetBranchAddress("muonPz",&muonPz);
  tree->SetBranchAddress("muonPt",&muonPt);
  Int_t entries = (Int_t)tree->GetEntries();

  cout<< entries << endl;

  TH1F *hist = new TH1F("hist", "Histogram", 100, -150., 150.);
  TH1F *hist2 = new TH1F("hist2", "Histogram2", 100, -150., 150.);
  TH1F *hist3 = new TH1F("hist3", "Histogram3", 100, -150., 150.);
  TH1F *hist4 = new TH1F("hist4", "Histogram4", 100, -150., 150.);
  TH1F *hist5 = new TH1F("hist5", "Histogram5", 100, 0., 150.);


  for(int i = 0; i < entries; i++)
    {
      //tree->GetEntry(i);                                                      
      //cout<< muonPx << "\t" << muonPy << "\t" << muonPz << "\t" << muonPz <<e\
ndl;                          
 hist->Fill(muonPx);
      hist2->Fill(muonPy);
      hist3->Fill(muonPz);
      hist4->Fill(muonPt);
      hist5->Fill(2*sqrt(muonPx*muonPx+muonPy*muonPy+muonPz*muonPz));
    }

  TCanvas *cH1 = new TCanvas("cH1","multipads",900,900);
  cH1->Divide(2,2,0,0);

  cH1->SetTickx();
  cH1->SetTicky();
       cH1->cd(1);
       hist->GetXaxis()->SetTitle("muonPx");
       hist->Draw();

       cH1->cd(2);
       hist2->GetXaxis()->SetTitle("muonPy");
       hist2->Draw();

       cH1->cd(3);
       hist3->GetXaxis()->SetTitle("muonPz");
       hist3->Draw();
       cH1->cd(4);
       hist4->GetXaxis()->SetTitle("muonPt");
       hist4->Draw();

       TCanvas *cH2 = new TCanvas();
       cH2->SetTickx();
       cH2->SetTicky();
       hist5->Draw();


  //input->Close();                                                             
}

// ---------------------------------
// End of my code 
// ---------------------------------

[couet]

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