three_body_higgs_decay.C

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double R_L(double x)
{
  double z = (91.1876*91.1876)/(x*x);
  
  double a = ((3.-16.*z+20.*z*z)/(sqrt(4.*z-1.)))*acos((3.*z-1.)/(2.*z*sqrt(z)));

  double b = ((1.-z)/(2.*z))*(2.-13.*z+15.*z*z);

  double c = 0.5*(3.-10.*z+4.*z*z)*log(z);

  return (a-b-c);

}



double R_T(double x)
{

  double y = (91.1876*91.1876)/(x*x);

  double s = ((3.*(1.-8.*y+20.*y*y))/(sqrt(4.*y-1)))*acos((3.*y-1)/(2.*y*sqrt(y)));

  double t = ((1.-y)/(2.*y))*(2.-13.*y+47.*y*y);

  double u = 1.5*(1.-6.*y+4.*y*y)*log(y);

  return (s-t-u);
}

double delta_z(double x)

{
  double sin = 0.23122;
  double s = 7./12. - (10./9.)*sin +(40./9.)*(sin)*(sin);

  return s;
}


double con(double x)
{
  double w = (91.1876**4)*((3.*1.166**2)/((16.*(10.**10.))*((TMath::Pi())**3)));
  
  return w;
}


void three_body_higgs_decay()
{
  TCanvas *c1 = new TCanvas("Probability","",600,600);
  
  c1->SetFillColor(40);
  
  
  hist = new TH1F("g1","",100,100,300);
  
  TF1 *f1 = new TF1("f1","1/(-(R_L(x)/R_T(x))/(R_L(x)/R_T(x)-1))",100,91.1876*2);
  TF1 *f2 = new TF1("f2","  ((91.1876**4)/(x**4))*(8/((1-((2*(91.1876**2))/(x**2)))**2))          ",91.1876*2,300);

  
  c1->cd();
  hist->SetTitle("#Gamma_{T}/#Gamma_{L}");  
  hist->TH1::SetStats(kFALSE);
  hist->GetXaxis()->SetTitle("Higgs Mass");
  hist->GetXaxis()->CenterTitle();

  
  hist->Draw();
  
  
  
  //  f1->GetYaxis()->SetTitle("");
  
  f1->Draw("same");
  f2->Draw("same");
  
  
  TCanvas *c2 = new TCanvas("Partial Width Z","",600,600);
  hist2 = new TH1F("g2","",100,100,182);
  
  // TF1 *f3 = new TF1("f3","R_T(x)",100,182);
  TF1 *f3 = new TF1("f3","x*con(x)*R_T(x)*delta_z(x)",100,182);
  
  c2->cd();
  hist2->SetTitle("Partial width of Higgs to Z Z* to Z fermion anti-fermion ");  
  hist2->TH1::SetStats(kFALSE);
  hist2->GetXaxis()->SetTitle("Higgs Mass");
  hist2->GetXaxis()->CenterTitle();


  hist2->Draw();
  
  f3->Draw("same");
  
}

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