  Form factors of composite operators in the SL(2) sector of N=4 SYM theory are
studied up to two loops via the on-shell unitarity method. The non-compactness
of this subsector implies the novel feature and technical challenge of an
unlimited number of loop momenta in the integrand's numerator. At one loop, we
derive the full minimal form factor to all orders in the dimensional
regularisation parameter. At two loops, we construct the complete integrand for
composite operators with an arbitrary number of covariant derivatives, and we
obtain the remainder functions as well as the dilatation operator for composite
operators with up to three covariant derivatives. The remainder functions
reveal curious patterns suggesting a hidden maximal uniform transcendentality
for the full form factor. Finally, we speculate about an extension of these
patterns to QCD.
