A good deal of progress has been made in the past two days as far as getting histograms for the reconstructed invariant mass. The program I wrote can now create a histogram for each jet in a given event, but I am still having trouble with saving the histograms all to .root files and adding them together. 

     As a good sign, if I restrict the program to only one jet in one event, then the histogram has the proper number of entries. For instance, a jet with 8 clusters has (7+6+5+4+3+2+1) = 28 entries in its histogram.