Measurement 1-Jetttiness event shape at High Q² using the H1 detector

First measurements of the 1-jettiness event shape observables are performed in neutral-current deep-inelastic scattering at HERA. The data amounting to an integrated luminosity of 351.6 pb^-1 were recorded with the H1 detector in the years 2003-2007 at √s = 319 GeV and the measurements are restricted to high momentum transfer Q² > 150 GeV². The 1-jettiness observable τ_1b is defined such that it is Lorentz invariant and equivalent to the thrust observable defined in the Breit frame. Triple-differential cross sections are presented as a function of τ_1b, Q², and the inelasticity y. The cross sections are sensitive to parton distribution functions of the proton, the strong coupling constant, parton shower, and hadronisation effects. The presence of events where one of the two hemispheres in the Breit frame is empty was confirmed for the first time, a phenomenon that was only predicted by perturbative QCD calculations and never previously measured. The data are compared to selected Monte Carlo predictions and higher-order pQCD calculations. This talk will discuss the implications of the results on a wide range of QCD phenomena that the measurements probe.