Novel 3+1 dimensional N = 2 superconformal field theories (with tensionless
BPS string solitons) are believed to arise when two sets of M5 branes inte
rsect over a 3+1 dimensional hyperplane. We derive a DLCQ description of th
ese theories as supersymmetric quantum mechanics on the Higgs branch of sui
table 4d N = 1 supersymmetric gauge theories. Our formulation allows us to
determine the scaling dimensions of certain chiral primary operators in the
conformal field theories. We also discuss general criteria for quantum mec
hanical DLCQ descriptions of supersymmetric field theories (and the resulti
ng multiplicities and scaling dimensions of chiral primary operators).