K–K excitations on AdS5×S5 as N=4 “primary” superfields

We show that the K–K spectrum of IIB string on AdS5×S5 is described by “twisted chiral” N=4 superfields, naturally described in “harmonic superspace”, obtained by taking suitable gauge singlets polynomials of the D3-brane boundary SU(n) superconformal field theory. To each p-order polynomial is associated a massive K–K short representation with 256×112p2(p2−1) states. The p=2 quadratic polynomial corresponds to the “supercurrent multiplet” describing the “massless” bulk graviton multiplet.