Probing the shape of jets, the strong coupling, and QCD using angularities

We predict the angularity spectra of hadrons produced in e+e- collisions to NNLL' accuracy in resummed perturbation theory with 2-loop fixed-order matching. Angularities are event shapes dependent on a continuously adjustable parameter a < 2, changing the sensitivity to radiation close to or far away from the thrust axis. They probe the dependence of hadronic jet structure on the running strong coupling alpha_s, and on nonperturbative corrections due to hadronization. The leading nonperturbative shift to the first moment of angularities is universal, dependent on a single universal parameter times 1/Q and 1/(1-a). We use soft-collinear effective theory (SCET) and Event2 to predict resummed spectra matched to fixed-order QCD, along with renormalon subtractions removing ambiguities in the perturbative and nonperturbative parts and improving perturbative convergence. We compare our final predictions to analysis from LEP and find excellent agreement. This is a strong test not only of perturbative QCD but also the prediction of nonperturbative universality in angularities.