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Hi Rooters!
Well, I’m working on TGraphError im going to show you bellow, but the exponential (gaussian fit) doesn’t work.
{
c1 = new TCanvas("c1","Pure Z/ Cross section vs Energy ",200,10,700,500);
c1->SetFillColor(42);
c1->SetGrid();
c1->GetFrame()->SetFillColor(21);
c1->GetFrame()->SetBorderSize(12);
const Int_t n = 15;
Double_t x[n] = {20, 30, 34.4, 40, 50, 60, 70, 80, 85, 90, 91, 95, 100, 110, 120};
Double_t y[n] = {7.19E-02,1.85E-01,2.63E-01,4.00E-01,8.27E-01,1.78E+00,4.51E+00,1.77E+01,5.72E+01,7.38E+02,1.40E+03,2.93E+02,1.02E+02,3.78E+01,2.13E+01};
Double_t ex[n] = {.0,.0,.0,.0,.0,.0,.0,.0,.0,.0,.0,.0,.0,.0,.0};
Double_t ey[n] = {3.58E-05,9.20E-05,1.30E-04,1.98E-04,4.19E-04,9.06E-04,2.30E-03,9.35E-03,3.72E-02,3.98E-01,7.50E-01,1.34E-01,5.56E-02,2.07E-02,1.17E-02};
gr = new TGraphErrors(n,x,y,ex,ey);
gr->SetTitle("Cross Section (pb) vs Energy (GeV)");
gr->SetMarkerColor(4);
gr->SetMarkerStyle(21);
gr->Draw("ALP");
TF1 *f1 = new TF1("f1","pol1(0)",20,75);
TF1 *f2 = new TF1("f2","[1400]*exp(-[1]*((x-[91])**2)/([2]*([0.5]**2)))",75,120);
f2->SetParameters(75,80,85,90,91,95,10,110,120);
gr->Fit("f1","R");
gr->Fit("f2","B");
gr->Draw();
}
It runs the commands without any problem but the fitting won’t show in the graph. I’m new to all this thing so, I hope I’m not disregarding something important.
Thank you in adnance!