breit-wigner fitting

  1. bwFit = ROOT.TF1("bwfit",bw,50.e3,200.e3) 
  2. bwFit.SetParameter(0,100.e3) 
  3. bwFit.SetParameter(1,1.e3)
  5. # Now fit the Breit-Wigner to the histogram, 
  6. # write the results as plot labels, 
  7. # and write the plot to the output file.
  9. dataHisto.Fit(bwFit ,"E") 
  10. dataHisto.Draw("pe")
  11. chi2 = bwFit.GetChisquare() 
  12. ndof = bwFit.GetNDF()
  13. mean = bwFit.GetParameter(0)/1000
  14. width = bwFit.GetParameter(1)/1000
  16. latex.DrawText(0.5,0.80,"Mean = %.1f GeV"%(mean)) 
  17. latex.DrawText(0.5,0.75,"Width = %.1f GeV"%(width)) 
  18. latex.DrawText(0.5,0.7,"chi2/ndof = %.1f/%d = %.1f"%(chi2,ndof,chi2/ndof))
  20. canvas.Print(plotFileName)