Using small number of s3 data events for benchmark

modified: dvcs.sh

benchmarks/dvcs/scripts/dvcs_ps_gen.cxx

+void dvcs_ps_gen() {
+  double E_p = 100.0;
+  double M_p = 0.938;
+  double E_e = 5.0;
+   TLorentzVector target(0.0, 0.0, std::sqrt(E_p*E_p - M_p*M_p),E_p);
+   TLorentzVector beam(0.0, 0.0, E_e, std::sqrt(E_e*E_e+0.000511*0.000511));
+   TLorentzVector W = beam + target;
+
+   //(Momentum, Energy units are Gev/C, GeV)
+   Double_t masses[3] = { 0.000511,0.938, 0.0} ;
+
+   TGenPhaseSpace event;
+   if(!event.SetDecay(W, 3, masses))
+     std::cout << "derp\n";
+     ;
+
+   TH2F *h2 = new TH2F("h2","h2; Q^{2} ; t", 100,0,5, 100,-0.120,0);
+
+   for (Int_t n=0;n<1000000;n++) {
+      Double_t weight = event.Generate();
+
+      TLorentzVector* pElectron = event.GetDecay(0);
+      TLorentzVector* pProton = event.GetDecay(1);
+      TLorentzVector* pGamma = event.GetDecay(2);
+
+      TLorentzVector pq = beam - *pElectron;
+      TLorentzVector Delta = target - *pProton;
+
+      h2->Fill(-1.0*(pq.M2()) , Delta.M2() ,weight);
+      //std::cout <<  -1.0*(pq.M2())  << " , " <<  Delta.M2() << " , " << weight << "\n";
+   }
+   h2->Draw("colz");
+}