Toward a NNLO calculation of the (B)over-bar → Xsγ decay rate with a cut on photon energy:: II.: Two-loop result for the jet function

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) over bar -> 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. (c) 2006 Elsevier B.V. All rights reserved.