Filling 2D Energy Theta Histogram

#include <math.h>
#include <TRandom3.h>

void Reverse3_Moller() {

       struct evt_t
       {
               Int_t event;
               Float_t FnlMom[3], MolMom[3];
       };

       ifstream in;
       in.open("Just_Scattered_Momentum_4e8.dat");
       evt_t evt;
       Int_t nlines=0;

       TLorentzVector Fnl_Lab_4Mom;
       TLorentzVector Mol_Lab_4Mom;
       TLorentzVector Fnl_CM_4Mom;
       TLorentzVector Mol_CM_4Mom;
       TLorentzVector CMS;

       TFile *f = new TFile("Reverse3_Moller_4e8.root","RECREATE");
       TTree *tree = new TTree("Moller","Moller data from ascii file");

       TH2F* MolEThetaCM=new TH2F("MolEThetaCM","Moller E and Theta CM",42,35,56,183,90,181);

       TH1F* FnlMomLab=new TH1F("FnlMomLab","Final Scattered Electron Momentum Lab Frame ",30000,0,15000);
       TH1F* MolMomLab=new TH1F("MolMomLab","Moller Momentum Lab Frame ", 12000,0,6000);
       TH1F* FnlMomCM=new TH1F("FnlMomCM","Final Scattered Electron Momentum CM Frame ",1000,40,60);
       TH1F* MolMomCM=new TH1F("MolMomCM","Moller Momentum CM Frame ",1000,40,60);

       TH1F* FnlThetaLab=new TH1F("FinalThetaLab","Final Scattered Electron Theta Lab Frame",200,0,1);
       TH1F* MolThetaLab=new TH1F("MolThetaLab","Moller Theta Lab Frame",2000,0,90);
       TH1F* FnlThetaCM=new TH1F("FnlThetaCM","Final Scattered Electron Theta CM Frame",360,0,90);
       TH1F* MolThetaCM=new TH1F("MolThetaCM","Moller Theta CM Frame",360,90,180);

       TH1F* FnlPhiCM=new TH1F("FnlPhiCM","Final Scattered Electron Phi in CM",720,-180,180);
       TH1F* MolPhiCM=new TH1F("MolPhiCM","Final Moller Phi in CM",720,-180,180);
       TH1F* FnlPhiLab=new TH1F("FnlPhiLab","Final Scattered Electron Phi in Lab",720,-180,180);
       TH1F* MolPhiLab=new TH1F("MolPhiLab","Final Moller Phi in Lab",720,-180,180);

       tree->Branch("evt",&evt.event,"event/I:FnlPx/F:FnlPy:FnlPz:MolPx:MolPy:MolPz");

       while(in.good())
       {
               evt.event=nlines;
               in >> evt.FnlMom[0] >> evt.FnlMom[1] >> evt.FnlMom[2] >> evt.MolMom[0] >> evt.MolMom[1] >> evt.MolMom[2];
               nlines++;
               tree->Fill();

               //Define using Final Moller momentum

                       //Define 4 vector
                               Mol_Lab_4Mom.SetPxPyPzE(evt.MolMom[0],evt.MolMom[1],evt.MolMom[2],
                                       sqrt(evt.MolMom[0]*evt.MolMom[0]+evt.MolMom[1]*evt.MolMom[1]+evt.MolMom[2]*evt.MolMom[2]+.511*.511));

               //Find 4 Momentum vector componets for Final Lab frame scattered electron
                       //Define 4vector

                               Fnl_Lab_4Mom.SetPxPyPzE(evt.FnlMom[0],evt.FnlMom[1],evt.FnlMom[2],
                                       sqrt(evt.FnlMom[0]*evt.FnlMom[0]+evt.FnlMom[1]*evt.FnlMom[1]+evt.FnlMom[2]*evt.FnlMom[2]+.511*.511));

       
                       //Boost vectors
                               CMS=Fnl_Lab_4Mom+Mol_Lab_4Mom;
                       //Boost to CM Frame  
                               Fnl_Lab_4Mom.Boost(-CMS.BoostVector());
                               Fnl_CM_4Mom=Fnl_Lab_4Mom;
                               Mol_Lab_4Mom.Boost(-CMS.BoostVector());
                               Mol_CM_4Mom=Mol_Lab_4Mom;
       
                       //Recover the original Final 4-Momentums
                               Fnl_Lab_4Mom.SetPxPyPzE(evt.FnlMom[0],evt.FnlMom[1],evt.FnlMom[2],
                                       sqrt(evt.FnlMom[0]*evt.FnlMom[0]+evt.FnlMom[1]*evt.FnlMom[1]+evt.FnlMom[2]*evt.FnlMom[2]+.511*.511));
                               Mol_Lab_4Mom.SetPxPyPzE(evt.MolMom[0],evt.MolMom[1],evt.MolMom[2],
                                       sqrt(evt.MolMom[0]*evt.MolMom[0]+evt.MolMom[1]*evt.MolMom[1]+evt.MolMom[2]*evt.MolMom[2]+.511*.511));
       
                               //Fill 2D Histogram with Moller Energy and Theta

                               if(Mol_Lab_4Mom.E()>500)
                               {
                                       MolEThetaCM->Fill(Mol_CM_4Mom.E(),(Mol_CM_4Mom.Theta()*180/3.14159265359));
       
                                       MolThetaCM->Fill(Mol_CM_4Mom.Theta()*180/3.14159265359);
                                       FnlThetaCM->Fill(Fnl_CM_4Mom.Theta()*180/3.14159265359);
                                       MolThetaLab->Fill(Mol_Lab_4Mom.Theta()*180/3.14159265359);
                                       FnlThetaLab->Fill(Fnl_Lab_4Mom.Theta()*180/3.13159265359);   
                                       FnlPhiLab->Fill(Fnl_Lab_4Mom.Phi()*180/3.14159265359);
                                       MolPhiLab->Fill(Mol_Lab_4Mom.Phi()*180/3.14159265359);
       
       
                                       MolMomLab->Fill(Mol_Lab_4Mom.P());
                                       FnlMomLab->Fill(Fnl_Lab_4Mom.P());
                                       MolMomCM->Fill(Mol_CM_4Mom.P());
                                       FnlMomCM->Fill(Fnl_CM_4Mom.P());
                                       FnlPhiCM->Fill(Fnl_CM_4Mom.Phi()*180/3.14159265359);
                                       MolPhiCM->Fill(Mol_CM_4Mom.Phi()*180/3.14159265359);
                               }
               }//End input loop
       
       in.close();
       tree->Print();  
       tree->Write(); 
       f->Write();
       delete tree;
       delete f;

}//End main