Central electron tracking

test central_electron.sh with updated silicon tracker geometry

benchmarks/tracking/scripts/gen_central_electrons.cxx

@@ -17,7 +17,7 @@ using namespace HepMC3;
 void gen_central_electrons(int n_events = 100, 
                      const char* out_fname = "central_electrons.hepmc")
 {
-  double cos_theta_min = std::cos( 140.0*(M_PI/180.0));
+  double cos_theta_min = std::cos( 10.0*(M_PI/180.0));
   double cos_theta_max = std::cos(170.0*(M_PI/180.0));
 
   WriterAscii hepmc_output(out_fname);