  In molecular collisions, resonances occur at specific energies where the
colliding particles temporarily form quasi-bound complexes, resulting in rapid
variations in the energy dependence of scattering cross sections.
Experimentally, it has proven challenging to observe such scattering
resonances, especially in differential cross sections. We report the
observation of resonance fingerprints in the state-to-state differential cross
sections for inelastic NO-He collisions in the 13 to 19 cm$^{-1}$ energy range
with 0.3 cm$^{-1}$ resolution. The observed structures were in excellent
agreement with quantum scattering calculations. They were analyzed by
separating the resonance contributions to the differential cross sections from
the background through a partitioning of the multichannel scattering matrix.
This revealed the partial wave composition of the resonances, and their
evolution during the collision.
