New particles at the TeV scale can decay hadronically with strongly
collimated jets, thus the standard reconstruction methods based on
invariant-masses of well-separated jets can fail. We discuss how to identify
such particles in pp collisions at the LHC using jet shapes which help to
reduce the contribution of QCD-induced events. We focus on a rather generic
example X to ttbar to hadrons, with X being a heavy particle, but the approach
is well suited for reconstruction of other decay channels characterized by a
cascade decay of known states.Comment: 14 pages, 6 figure