title: Rapidity renormalization group.
abstract: We introduce a systematic approach for the resummation of perturbative series which involves large logarithms not only due to large invariant mass ratios but large rapidities as well. A series of this form can appear in a variety of gauge theory observables. The formalism is utilized to calculate the jet broadening event shape in a systematic fashion to next-to-leading logarithmic order. An operator definition of the factorized cross section as well as a closed form of the next-to-leading-log cross section are presented. The result agrees with the data to within errors.
authors.affiliation: Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Jui-yu
authors.initials: JY
authors.lastname: Chiu
authors.forename: Ambar
authors.initials: A
authors.lastname: Jain
authors.forename: Duff
authors.initials: D
authors.lastname: Neill
authors.forename: Ira Z
authors.initials: IZ
authors.lastname: Rothstein