摘要: : We study the form factors of the Konishi operator, the prime example of nonprotected
operators in N = 4 SYM theory, via the on-shell unitarity method. Since the
Konishi operator is not protected by supersymmetry, its form factors share many features
with amplitudes in QCD, such as the occurrence of rational terms and of UV divergences
that require renormalization. A subtle point is that this operator depends on the spacetime
dimension. This requires a modification when calculating its form factors via the on-shell
unitarity method. We derive a rigorous prescription that implements this modification to all
loop orders and obtain the two-point form factor up to two-loop order and the three-point
form factor to one-loop order. From these form factors, we construct an IR-finite crosssection-type
quantity, namely the inclusive decay rate of the (off-shell) Konishi operator
to any final (on-shell) state. Via the optical theorem, it is connected to the imaginary part
of the two-point correlation function. We extract the Konishi anomalous dimension up to
two-loop order from it.