Use Case II: Creating Histograms

Using ROOT's commands to improve the quality of the resulting plots

A number of settings can be used to make the plots that ROOT generates look better than the default.  Here are examples of different commands:

Note: gStyle is one of ROOT's global variables used to control the overall settings for all plots.

gStyle->SetStatW(0.30);

gStyle->SetStatH(0.20);

gStyle->SetStatColor(42);

gStyle->SetOptStat(10);

Suppose t1 is a TTree*, then you can set the following:

t1->SetLineWidth(4);

t1->SetMarkerStyle(4);

t1->SetMarkerSize(0.5);

t1->SetMarkerColor(4);

t1->SetFillColor(5);

TKR

CAL

ACD

 This use case will demonstrate looking at the ACD Active Distance Distribution.

1. Start up ROOT and open the ROOT summary ntuple and access the ntuple TTree as demonstrated in Use Case I.

2. Set up to create plots as demonstrated in Use Case II .

3. Create the TCuts to be applied when creating the new histogram.
   
   In this case, we wish only to keep those events that had:
   
   • 3-in-a-row in the TKR (GltWord & 4)
   • An Active Distance value over -200 (AcdActiveDist >-200)
   • At least one reconstructed track (TkrNumTracks > 0)




4. Now create a 1-Dimensional Histogram for ActiveDistance using the command:

t->Draw("AcdActiveDist", trackCut && threeinarow && goodActiveDist)

This should produce a histogram simalar to:

Owned by: Heather Kelly