The effects of the soft gluon emission in hard scattering processes at thephase boundary are resummed in the soft-collinear effective theory (SCET). InSCET, the soft gluon emission is decoupled from the energetic collinear part,and is obtained by the vacuum expectation value of the soft Wilson-lineoperator. The form of the soft Wilson lines is universal in deep inelasticscattering, in the Drell-Yan process, in the jet production from e+e-collisions, and in the gamma* gamma* -> pi0 process, but its analytic structureis slightly different in each process. The anomalous dimensions of the softWilson-line operators for these processes are computed along the light-likepath at leading order in SCET and to first order in alpha_s, and therenormalization group behavior of the soft Wilson lines is discussed.
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