  Kinematic edges of cascade decays of new particles produced in high-energy
collisions may provide important constraints on the involved particles' masses.
For the exemplary case of gluino decay $\tilde{g}\to q\bar q \tilde{\chi}$ into
a pair of quarks and a neutralino through a squark resonance, we study the
hadronic invariant mass distribution in the vicinity of the kinematic edge. We
perform a next-to-leading order calculation in the strong coupling $\alpha_s$
and the ratio of squark width and squark mass $\Gamma_\tilde{q}/m_\tilde{q}$,
based on a systematic expansion in $\Gamma_\tilde{q}/m_\tilde{q}$. The
separation into hard, collinear and soft contributions elucidates the process
dependent and universal features of distributions in the edge region,
represented by on-shell decay matrix elements, universal jet functions and a
soft function that depends on the resonance propagator and soft Wilson lines.
