7 TFile *
f =
new TFile(
"hd_root.root");
8 TTree *geant = (TTree*)gROOT->FindObject(
"geant");
9 TTree *dana = (TTree*)gROOT->FindObject(
"dana");
11 TCanvas *
c1 =
new TCanvas(
"c1");
15 geant->SetMarkerStyle(6);
16 geant->SetMarkerSize(0.1);
18 geant->Draw(
"P:sqrt(x*x+y*y)",
"P>0.95");
19 dana->Draw(
"P:sqrt(x*x+y*y)",
"",
"same");
21 TLatex *lab =
new TLatex(400.0, 1.005,
"single 1GeV/c proton #theta=5^{o} #phi=180^{o}");
22 lab->SetTextSize(0.03);
25 geant->SetLineColor(geant->GetMarkerColor());
26 dana->SetLineColor(dana->GetMarkerColor());
27 geant->SetLineWidth(4.0);
28 dana->SetLineWidth(4.0);
30 TLegend *
leg =
new TLegend(0.5, 0.5, 0.7, 0.7);
31 leg->SetFillColor(kWhite);
32 leg->AddEntry(geant,
"GEANT");
33 leg->AddEntry(dana,
"DANA");
36 c1->SaveAs(
"P_vs_r.pdf");
37 c1->SaveAs(
"P_vs_r.gif");