  If new particles are discovered at the LHC, it will be important to determine
their spins in as model-independent a way as possible. We consider the case,
commonly encountered in models of physics beyond the Standard Model, of a new
scalar or fermion $D$ decaying sequentially into other new particles $C,B,A$
via the decay chain $D\to C q$, $C\to B l^{near}$, $B\to A l^{far}$, $l^{near}$
and $l^{far}$ being opposite-sign same-flavour charged leptons and $A$ being
invisible. We compute the observable 2- and 3-particle invariant mass
distributions for all possible spin assignments of the new particles, and
discuss their distinguishability using a quantitative measure known as the
Kullback-Leibler distance.
