  We study the (2,0) superconformal theories in six dimensions, which arise
from the low-energy limit of k coincident 5-branes, using their discrete
light-cone formulation as a superconformal quantum mechanical sigma model. We
analyze the realization of the superconformal symmetry in the quantum
mechanics, and the realization of primary operators. As an example we compute
the spectrum of chiral primary states in symmetric Spin(5)_R representations.
To facilitate the analysis we introduce and briefly discuss a new class of
Lorentz non-invariant theories, which flow in the IR to the (2,0)
superconformal field theories but differ from them in the UV.
