  We consider the mass distribution of QCD jets after the application of jet
substructure methods, specifically the mass-drop tagger, pruning, trimming and
their variants. In contrast to most current studies employing Monte Carlo
methods, we carry out analytical calculations at the next-to-leading order
level, which are sufficient to extract the dominant logarithmic behaviour for
each technique, and compare our findings to exact fixed-order results. Our
results should ultimately lead to a better understanding of these jet
substructure methods which in turn will influence the development of future
substructure tools for LHC phenomenology.
