Introduction

For photon+jet analyses we need information stored in both gamma trees and jet trees.  I wrote a basic code skeleton that can serve as an example for how to read them both in.  The code attempts to match photon candidates to jet candidates.  Not all photon candidates match to jet candidates, likely because of differences in photon candidate finding (just looking for clusters) and jet finding (applying a mid point cone algorithm with various thresholds).

Documentation for each tree type

Jet tree format changed in 2009.  The new format is documented here.

The gamma tree code is mostly "self documenting."  There are some directions here, although code now resides in cvs at StRoot/StGammaMaker, and not in the offline area.

Directions for using this code

Step 1: compile

mkdir myPhoJetAna

cd myPhoJetAna

cvs co offline/users/aliceb/StRoot/StBetaPhoJetReader/

mv offline/users/aliceb/StRoot .

stardev

cons

Step 2: run over data or Monte Carlo.

See in the macros directory scripts for running over 2006 data trees (runGammaJetTreeReader.C) and trees produced from 2006 offical simulation ( runGammaJetTreeReaderMC.C)

Step 3: change and improve for your purposes.

The source code contains notes about where to add additional histograms if you would like them.  You could also consider making another simple tree to store information about each event for further analysis.

Note: the sched directory contains the scripts that I used to submit the trees for processing.