Worldsheet spectrum in AdS4/CFT3 correspondence

The AdS4/CFT3 duality is a new example of an integrable and exactly solvable AdS/CFT system. There is, however, a puzzling mismatch between the number of degrees of freedom used in the exact solution (4B + 4F scattering states) and 8B + 8F transverse oscillation modes of critical superstring theory. We offer a resolution of this puzzle by arguing that half of the string modes dissolve in the continuum of two-particle states once α' corrections are taken into account. We also check that the conjectured exact S-matrix of AdS4/CFT3 [1] agrees with the tree-level worldsheet calculation.