We provide an $M$ theory interpretation of the recently discovered $\mathcal{N}=8$ supersymmetric Chern-Simons theory with $SO(4)$ gauge symmetry. The theory is argued to describe two membranes moving in the orbifold ${\mathbf{R}}^8/{\mathbf{Z}}_2$. At level $k=1$ and $k=2$, the classical moduli space $\mathcal{M}$ coincides with the infrared moduli space of $SO(4)$ and $SO(5)$ super Yang-Mills theory, respectively. For higher Chern-Simons level, the moduli space is a quotient of $\mathcal{M}$. At a generic point in the moduli space, the massive spectrum is proportional to the area of the triangle formed by the two membranes and the orbifold fixed point.

• Received 18 April 2008

DOI:https://doi.org/10.1103/PhysRevLett.101.041602