Power Corrections to e + e − Dijet Event Shapes ⋆ Carola

Power Corrections to e + e − Dijet Event Shapes ⋆

We discuss a class of event shapes for ee dijet events that include the thrust as a special case. Large logarithmic corrections to the corresponding cross sections can be resummed to all logarithmic orders at leading power. However, irrespective of the order up to which the perturbative expansion is calculated, it has to be supplemented by nonperturbative corrections due to its at best asymptot...

Dijet Event Shapes as Diagnostic Tools

Event shapes have long been used to extract information about hadronic final states and the properties of QCD, such as particle spin and the running coupling. Recently, a family of event shapes, the angularities, has been introduced that depends on a continuous parameter. This additional parameter-dependence further extends the versatility of event shapes. It provides a handle on nonperturbativ...

Event Shape/Energy Flow Correlations

We introduce a set of correlations between energy flow and event shapes that are sensitive to the flow of color at short distances in jet events. These correlations are formulated for a general set of event shapes, which includes jet broadening and thrust as special cases. We illustrate the method for e+e− dijet events, and calculate the correlation at leading logarithm in the energy flow and a...

EVENT SHAPES AND POWER CORRECTIONS IN e + e − ANNIHILATION

On power corrections to event shapes

Recent work on the theme of power corrections in perturbative QCD is briefly reviewed, with an emphasis on event shapes in e+e− annihilation. The factorization of soft gluon effects is the main tool: it leads to resummation, and thus highlights the limitations of perturbation theory, pointing to nonperturbative corrections whose size can be estimated. Power corrections can be resummed into shap...