B-decays in the heavy-quark expansion

Progress in the theoretical description of B-meson decays, in particular decays to light hadrons, is reviewed. The factorization properties of such decays can be analyzed using the soft-collinear effective theory. Applications of the effective theory to both inclusive and exclusive decays are discussed.Comment: Talk presented at the 15th Topical Conference on Hadron Collider Physics (Michigan State University, June 2004) and at the 11th International QCD Conference (Montpellier, July 2004). 14 pages, 4 figure

Factorization and Resummation for Jet Broadening

Jet broadening is an event-shape variable probing the transverse momenta of particles inside jets. It has been measured precisely in e+e- annihilations and is used to extract the strong coupling constant. The factorization of the associated cross section at small values of the broadening is afflicted by a collinear anomaly. Based on an analysis of this anomaly, we present the first all-order expressions for jet-broadening distributions, which are free of large perturbative logarithms in the two-jet limit. Our formulae reproduce known results at next-to-leading logarithmic order but also extend to higher orders.Comment: 15 pages, 4 figure

Event-Based Transverse Momentum Resummation

We have developed a framework for automated transverse momentum resummation for arbitrary electroweak final states based on reweighting tree-level events. It is fully differential in the kinematics of the electroweak final states, which facilitates a straightforward analysis of arbitrary observables in the small transverse momentum region. We have implemented the resummation at next-to-next-to-leading logarithmic accuracy and match to next-to-leading fixed-order results using the event generator MadGraph5_aMC@NLO. Results for $Z$ and $W$ boson production with leptonic decay as well as $WZ$ production are presented. We compare to experimental measurements for the transverse momentum and the angular observable $\phi^*$.Comment: 28 pages, 13 figures. v2: journal versio