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Description
The H1 Collaboration at HERA reports the first measurement of groomed event shapes in deep inelastic e−p and e+p scattering (DIS) at $\sqrt{s} = 319$ GeV, using data recorded between 2003 and 2007 with an integrated luminosity of $351.1\pm 9.5$ pb$^{−1}$. Event shapes in DIS collisions provide incisive probes of perturbative and non-perturbative QCD, and recently developed grooming techniques investigate similar physics in jet measurements of hadronic collisions. This paper presents the first application of grooming to DIS data. The analysis is carried out in the Breit frame, utilizing the novel Centauro jet clustering algorithm that is designed for DIS event topologies. Events are required to have squared momentum–transfer $Q^2 > 150$ GeV$^2$ and inelasticity $0.2 < y < 0.7$. We report measurements of the production cross section of groomed event 1-jettiness and groomed invariant jet mass for several choices of grooming parameter. The measurements are compared to Monte Carlo models and to analytic calculations based on Soft Collinear Effective Theory (SCET).