  Ergodic many-body systems are expected to reach quasi-thermal equilibrium.
Here we demonstrate that, surprisingly, high-energy electrons, which are
injected into a quantum Hall edge mode with finite range interactions,
stabilize at a far-from-thermalized state over a long time scale. To detect
this non-equilibrium state, one positions an energy-resolved detector
downstream of the point of injection. So far, non-equilibrium distributions in
integrable systems were either found not to display relaxation at all, or
generically relax to near-thermal asymptotic states. In stark contrast, the
here-obtained many-body state comprises fast-decaying transient components,
followed by a nearly frozen distribution with a peak near the injection energy.
