  For a long time, it has been thought that 2D Fermi gases could support
long-lived excitations, thanks to the collinear quasiparticle scattering
controlled by phase space constraints at a 2D Fermi surface. We present a
direct calculation that reveals such excitations. The excitation lifetimes are
found to exceed the fundamental bound set by Landau Fermi-liquid theory by a
factor as large as $(T_F/T)^\alpha$ with $\alpha \approx 2$. These excitations
represent Fermi-surface modulations of an odd parity, one per each odd angular
momentum. To explain this surprising behavior, we employ a connection between
the linearized quantum kinetic equation and the dynamics of a fictitious
quantum particle moving in a 1D reflectionless ${\rm sech^2}$ potential. In
this framework, we identify the long-lived excitations in Fermi gases as zero
modes that arise from supersymmetry.
