Power Corrections to Event Shapes

Event shape variables in e+e- annihilation serve as an instrument to explore the interface be-tween perturbative QCD and non-perturbative effects. Due to soft and collinear gluon emissions, perturbative series suffer from enhanced logarithmic coefficents. Another contribution to large co-efficents are infrared renormalons that lead to non-perturbative power corrections. Dressed gluon exponentiation is applied to resum the large logarithms and the renormalons at the same time. Ambiguities in the result provide us with information on the shape of power corrections. The obtained descriptions of event shapes are confronted with the data. 2 Acknowledgements I’m very glad that I chose to contact Eric Laenen when I wanted to start working on my thesis. Although this meant that I had to travel from Utrecht to Amsterdam frequently, I had the oppor-tunity to work with a very interesting and beautiful theory (QCD), I got to know the NIKHEF institute and Eric turned out to be a very good supervisor. I am very grateful to Eric for his support, encouragements and confidence. Even though at one point there were 6 master student