BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Observation and differential cross section measurement of neutral current DIS events with an empty hemisphere in the Breit frame DTSTART:20240521T140000Z DTEND:20240521T150000Z DTSTAMP:20260915T093000Z UID:indico-event-1353@conference.ippp.dur.ac.uk DESCRIPTION:Speakers: Daniel Reichelt (Durham University\, IPPP)\n\nDaniel will review recent work done in the H1 collaboration on differential meas urements in Neutral-current DIS (https://arxiv.org/abs/2403.08982):The Bre it frame provides a natural frame to analyze lepton-proton scattering even ts. In this reference frame\, the parton model hard interactions between a quark and an exchanged boson defines the coordinate system such that the struck quark is back-scattered along the virtual photon momentum direction . In Quantum Chromodynamics (QCD)\, higher order perturbative or non-pertu rbative effects can change this picture drastically. As Bjorken-x decrease s below one half\, a rather peculiar event signature is predicted with inc reasing probability\, where no radiation is present in one of the two Brei t-frame hemispheres and all emissions are to be found in the other hemisph ere. At higher orders in αs or in the presence of soft QCD effects\, pred ictions of the rate of these events are far from trivial\, and that motiva tes measurements with real data. We report on the first observation of the empty current hemisphere events in electron-proton collisions at the HERA collider using data recorded with the H1 detector at a center-of-mass ene rgy of 319 GeV. The fraction of inclusive neutral-current DIS events with an empty hemisphere is found to be 0.0112±3.9%stat±4.5%syst±1.6%mod in the selected kinematic region of 150