  The complete two-loop expression for the jet function J(p^2,mu) of
soft-collinear effective theory is presented, including non-logarithmic terms.
Combined with our previous calculation of the soft function S(omega,mu), this
result provides the basis for a calculation of the effect of a photon-energy
cut in the measurement of the B-->X_s+gamma decay rate at
next-to-next-to-leading order in renormalization-group improved perturbation
theory. The jet function is also relevant to the resummation of Sudakov
logarithms in other hard QCD processes.
