Nonholomorphic N=2 terms in N=4 super Yang-Mills theory: 1-loop calculation in N=2 superspace

Abstract The effective action of N =2 gauge multiplets in general includes higher-dimension UV finite nonholomorphic corrections integrated with the full N =2 superspace measure. By adding a hypermultiplet in the adjoint representation we study the effective action of N =4 super Yang-Mills theory. The nonanomalous SU (4) R-symmetry of the classical N =4 theory must also be present in the on-shell effective action, and therefore we expect to find similar nonholomorphic terms for each of the scalars in the hypermultiplet. The N =2 path integral quantization formalism developed in projective superspace allows us to compute these hypermultiplet nonholomorphic terms directly in N =2 superspace. The corresponding gauge multiplet expression can be successfully compared with the result inferred from a N =1 calculation in the abelian subsector.