1/sigma * dsigma/deta

Roofit and RooStats
1

Dear Root Experts,

I am having some problems when I try to plot a variable 1/sigma dsigma/deta. I have successfully plotted the 1/N *dN/deta. Please see the attached plots.

eta.w.r.t-sigma.jpg845×635 23.3 KB


eta.w.r.t-events.jpg696×472 16.5 KB

I have generated N=1000 events using pythia and generated cross reproted by pythia output is 1.98*10^-8 mb or 19.28 fb and if I convert this to Luminosity this corresponds to 51.86 fb^-1.

I have been trying to plot the 1/sigma dsigma/deta Vs eta but I don’t know where I am getting wrong. I get 0 Entries when I try to do it with 1/sigma dsigma/deta. Please find the attachment containg plots.

I would be grateful for spotting the error and helping me out

I try to do it in the fallowing way… Here is only a chunk of code.

TH1F *TopEta = new TH1F(“eta”,“Eta of Top”, 100, -5., 5.);
TH1F *h3 = new TH1F(*TopEta);

TH1F *TopEta2 = new TH1F(“eta2”,“Eta2 of Top”, 100, -5., 5.);
TH1F *h4 = new TH1F(*TopEta2);

double a=129./nEvent;
double b=0;

double c=pythia.info.sigmaGen()/( 0.1 * nEvent);
double d=0;

h3->Add(TopEta,TopEta,a,b);
h4->Add(TopEta2,TopEta2,c,d);

Thank you for your anticipation.