Event Shape Variables measured in ep Deep-Inelastic Scattering

Deep inelastic ep scattering data taken with the H detector at HERA are used to study event shape variables over a large range of relevant energy Q between GeV and GeV Previously published analyses on thrust jet broadening jet mass and C parameter are substantially re ned and updated di erential two jet rates treated as event shapes are presented for the rst time The Q dependence of the mean values is t to second order calculations of perturbative QCD applying power law corrections proportional to Q to account for hadronization e ects The concept of these power corrections is tested by a systematic investigation in terms of a non perturbative parameter p and the strong coupling constant