Measurement of event shapes in deep inelastic scattering at HERA

TL;DR

This paper measures event-shape variables in deep inelastic scattering at HERA, comparing results with NLO calculations and non-perturbative corrections to test theoretical models across a wide kinematic range.

Contribution

It provides the first comprehensive measurement of event shapes in the Breit frame in DIS and tests the applicability of NLO and power correction models.

Findings

Q dependence of shape variables agrees with NLO predictions

Non-perturbative power corrections improve data description

Results extend the kinematic range of previous measurements

Abstract

Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6, where Q^2 is the virtuality of the exchanged boson and x is the Bjorken variable. The Q dependence of the shape variables has been used in conjunction with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative corrections (`power corrections') to investigate the validity of this approach.