Browsing by Author "H1 Collaboration"

Now showing 1 - 4 of 4
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    Measurement of charged particle multiplicity distributions in DIS at HERA and its implication to entanglement entropy of partons
    (Springer Nature, 2021) H1 Collaboration
    Charged particle multiplicity distributions in positron-proton deep inelastic scattering at a centre-of-mass energy s√=319 GeV are measured. The data are collected with the H1 detector at HERA corresponding to an integrated luminosity of 136 pb−1. Charged particle multiplicities are measured as a function of photon virtuality Q2, inelasticity y and pseudorapidity η in the laboratory and the hadronic centre-of-mass frames. Predictions from different Monte Carlo models are compared to the data. The first and second moments of the multiplicity distributions are determined and the KNO scaling behaviour is investigated. The multiplicity distributions as a function of Q2 and the Bjorken variable xbj are converted to the hadron entropy Shadron, and predictions from a quantum entanglement model are tested.
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    Measurement of exclusive π+π− and ρ0 meson photoproduction at HERA
    (Springer, 2020) H1 Collaboration
    Exclusive photoproduction of ρ0(770) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction γp→π+π−Y. Reactions where the proton stays intact (mY=mp) are statistically separated from those where the proton dissociates to a low-mass hadronic system (mp
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    Measurement of groomed event shape observables in deep-inelastic electron-proton scattering at HERA
    (Springer Nature, 2024) H1 Collaboration
    The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at $$\sqrt{s} =319~$$GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of 351 $$\textrm{pb}^{-1}$$. Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet measurements in 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 mass for several choices of grooming parameter. Monte Carlo model calculations and analytic calculations based on Soft Collinear Effective Theory are compared to the measurements.
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    Measurement of Lepton-Jet Correlation in Deep-Inelastic Scattering with the H1 Detector Using Machine Learning for Unfolding
    (American Physical Society, 2022) H1 Collaboration
    The first measurement of lepton-jet momentum imbalance and azimuthal correlation in lepton-proton scattering at high momentum transfer is presented. These data, taken with the H1 detector at HERA, are corrected for detector effects using an unbinned machine learning algorithm (multifold), which considers eight observables simultaneously in this first application. The unfolded cross sections are compared with calculations performed within the context of collinear or transverse-momentum-dependent factorization in quantum chromodynamics as well as Monte Carlo event generators.