Hi
I’m searching on the root manuel if there is a simple way to do differential plots on root. for example dsigma/dtheta for example.
Is there any way?
Thx. c.
Hi
I’m searching on the root manuel if there is a simple way to do differential plots on root. for example dsigma/dtheta for example.
Is there any way?
Thx. c.
To do a differential plot is just a normalisation technique really.
So to plots theta from tree t
t->Draw("theta>>h");
and to plot dsigma/dtheta:
h->Scale(norm)
where norm will be your normalisation factor which is normally the cross-section (x branching ratio) divided by the total number of events.
e.g.
Say I work out a cross section (145pb) and branching fraction (0.13) with pythia, then I use the detector software to make 1000 events and 360 are reconstructible after various cuts and detector limitations
sigma=145
bf=0.13
N=1000
draw and stick in histo h:
t->Draw("theta>>h", "(cut1<10)")
h->Scale((sigma*bf/N))
h->GetYaxis()->SetTitle("dsigma/dtheta")
h->GetXaxis()->SetTitle("theta (rad)")
h->Draw();