  We construct a class of pure quark and gluon observables by using the
collinear drop grooming technique. The construction is based on linear
combinations of multiple cumulative distributions of the jet mass in collinear
drop, whose specific weights are fully predicted perturbatively. This yields
observables which obtain their values purely from quarks (or purely from
gluons) in a wide region of phase space. We demonstrate this by showing that
these observables are effective in two phase space regions, one dominated by
perturbative resummation and one dominated by nonperturbative effects. The
nonperturbative effects are included using shape functions which only appear as
a common factor in the linear combinations constructed. We test this
construction using a numerical analysis with next-to-leading logarithmic
resummation and various shape function models, as well as analyzing these
observables with Pythia and Vincia. Choices for the collinear drop parameters
are optimized for experimental use.
