pi0 data set

Created scripts for single pi0 data set

ecal/scripts/emcal_pi0.cxx

+//////////////////////////////////////////////////////////////
+// Crystal EMCAL detector 
+// Single Pion dataset
+// J.KIM 10/18/2020
+//////////////////////////////////////////////////////////////
+#include "HepMC3/GenEvent.h"
+#include "HepMC3/ReaderAscii.h"
+#include "HepMC3/WriterAscii.h"
+#include "HepMC3/Print.h"
+
+#include <iostream>
+#include<random>
+#include<cmath>
+#include <math.h>
+#include <TMath.h>
+
+using namespace HepMC3;
+
+void emcal_pi0(int n_events = 1e6, const char* out_fname = "./data/emcal_pi0_0GeVto30GeV_100kEvt.hepmc")
+{
+  WriterAscii hepmc_output(out_fname);
+  int events_parsed = 0;
+  GenEvent evt(Units::GEV, Units::MM);
+
+  // Random number generator
+  TRandom *r1 = new TRandom();
+
+  for (events_parsed = 0; events_parsed < n_events; events_parsed++) {
+    // FourVector(px,py,pz,e,pdgid,status)
+    // type 4 is beam
+    // pdgid 11 - electron
+    // pdgid 111 - pi0
+    // pdgid 2212 - proton
+    GenParticlePtr p1 =
+        std::make_shared<GenParticle>(FourVector(0.0, 0.0, 10.0, 10.0), 11, 4);
+    GenParticlePtr p2 = std::make_shared<GenParticle>(
+        FourVector(0.0, 0.0, 0.0, 0.938), 2212, 4);
+
+    // Define momentum
+    Double_t p = r1->Uniform(0.0,30.0);
+    Double_t px;
+    Double_t py;
+    Double_t pz;
+    // Generates random vectors, uniformly distributed over the surface of a
+    // sphere of given radius, in this case momentum.
+    r1->Sphere(px, py, pz, p);
+
+    // type 1 is final state
+    // pdgid 111 - pi0 135 MeV/c^2
+    GenParticlePtr p3 = std::make_shared<GenParticle>(
+        FourVector(
+            px, py, pz,
+            sqrt(p*p + (0.134976*0.134976))),
+        111, 1);
+
+    GenVertexPtr v1 = std::make_shared<GenVertex>();
+    v1->add_particle_in(p1);
+    v1->add_particle_in(p2);
+
+    v1->add_particle_out(p3);
+    evt.add_vertex(v1);
+
+    if (events_parsed == 0) {
+      std::cout << "First event: " << std::endl;
+      Print::listing(evt);
+    }
+
+    hepmc_output.write_event(evt);
+    if (events_parsed % 10000 == 0) {
+      std::cout << "Event: " << events_parsed << std::endl;
+    }
+    evt.clear();
+  }
+  hepmc_output.close();
+  std::cout << "Events parsed and written: " << events_parsed << std::endl;
+}