void plot_res(){

  gROOT->Reset();
  gROOT->SetStyle("Plain");

  gROOT->ForceStyle();

  gStyle->SetOptStat(0);
  gStyle->SetOptFit(000);

  gStyle->SetTitleX(0.1f);
  gStyle->SetTitleW(0.8f);
  gStyle->SetTextSize(1.5);
  
  gStyle->SetTitleFont(132,"xy");
  gStyle->SetLabelFont(132,"xy");

  //  gStyle->SetLabelFont(62,"xy");

  //  gStyle->SetLabelSize(0.073,"xy");
  //  gStyle->SetTitleSize(0.086,"xy");

  gStyle->SetLabelSize(0.055,"xy");
  gStyle->SetTitleSize(0.065,"xy");

  gStyle->SetTitleOffset(1.0,"x");
  gStyle->SetTitleOffset(0.8,"y");


  //  double x[11] = {0.25, 0.75, 1.25, 1.75, 3.25, 4.25, 5.25, 6.26, 7.25, 8.25, 9.25};
  
  //  double res[11]={0.416, 0.348, 0.326, 0.237, 0.206, 0.184, 0.172, 0.162, 0.156, 0.149, 0.143};
  //  double eres[11]={3e-3, 6.9e-3, 7.5e-3, 2.8e-3, 1.6e-3, 2.6e-3, 3.4e-3, 5e-3, 7.4e-3, 8.6e-3, 1.1e-2};

  double x[11]    = {0.75,   1.25,   1.75, 2.25, 3.25, 4.25, 5.25, 6.26, 7.25, 8.25, 9.25};
  double res[11]  = {0.357,  0.322,  0.279, 0.24, 0.206, 0.184, 0.172, 0.162, 0.156, 0.149, 0.143};
  double eres[11] = {6.9e-3, 4.4e-3,  3.0e-3, 2.e-3, 1.6e-3, 2.6e-3, 3.4e-3, 5e-3, 7.4e-3, 8.6e-3, 1.1e-2};

  double ex[11];
  
  memset(ex,0,sizeof(ex));

  for(int ii = 0; ii < 11;ii++){
    
    res[ii] = res[ii]/1.03;
    eres[ii] = eres[ii]/10.;
  }

  TCanvas *c1 = new TCanvas("c1","Test",200,10, 600, 400);

  gPad->SetBottomMargin(0.15);
  gPad->SetTopMargin(0.05);
  gPad->SetLeftMargin(0.15);
  gPad->SetRightMargin(0.05);

  TF1 *f1 = new TF1("f1","sqrt([0]*[0]/x + [1]*[1])",0.75, 9.);


  TGraphErrors *gr  = new TGraphErrors(11,x,res,ex,eres);


  f1->SetLineColor(2);
  f1->SetLineWidth(2);

  gr->SetMaximum(0.4);

  gr->Fit(f1,"","",0.75,10.);

  
  gr->SetMarkerStyle(20);
  gr->SetMarkerSize(1.2);
  gr->SetMarkerColor(4);

  gr->GetXaxis()->SetTitle("Energy (GeV)");
  gr->GetYaxis()->SetTitle("#sigma_{t}   (ns)");

  gr->SetTitle("");

  gr->Draw("AP");

  TLatex *text = new TLatex(4, 0.3, "#sigma_{t} (ns) = #frac{0.32 }{#sqrt{E}} #otimes 0.09   ");

  //  TLatex Tl;
  //  Tl.SetTextAlign(12);
  //  Tl.SetTextSize(0.04);
  //  Tl.DrawLatex(4, 0.3, "#sigma_{t} (ns) = #frac{0.32 ns}{#sqrt{E}} #otimes 0.09 ns  ");

  text -> SetTextFont(132);
  text->SetTextSize(0.07);
  text->Draw();

}