Session E12: Jet Physics at the EIC – II

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The future Electron-Ion Collider (EIC) will use electrons to image the quarks and gluons inside nucleons with unprecedented precision. It thus offers great discovery potential to reveal the inner workings of the strong nuclear force, including the origin of the nucleon spin, mass, radius and other properties.The EIC will not only allow us to extend studies from fixed-target experiments to uncharted kinematic regions, but also will give us a novel,powerful tool: jets. In this talk, I will focus on the prospects of using jets to enable a quantum tomography of the proton at the EIC. I will discuss the experimental feasibility of key measurements that will exploit the unprecedented combination of hermetic tracking, particle identification, and calorimetry of the future EIC detectors. I will argue that a jet program at the EIC could unleash a new era in the field of 3D imaging of the nucleon.   

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We present a study of the jet performance of future EIC detectors. We use the Delphes3 program to perform fast simulations of detector response in high Q2 DIS events simulated with Pythia8. We use the detector parameters and geometry established as reference in the EIC yellow report. We investigate the potential to tag jets with neutral hadrons using the energy-flow algorithm as implemented in Delphes3. We focus on studying the impact of the hadronic calorimeter resolution on and coverage, especially on the central detector region. Our results will help guide future studies with detailed Geant-4 simulations.   

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Azimuthal di-hadron correlations in deeply inelastic scattering (DIS) have been considered as one of the golden channels to probe gluon saturation effects at the future Electron-Ion Collider (EIC). A suppression in the yield of back-to-back hadrons when comparing electron-proton with electron-nucleus collisions could be indicative of the onset of gluon saturation. A complementary measurement is the correlations of direct photons with hadrons/jets which has been studied in proton-nucleus collisions, yielding similar theoretical conclusions about the effects of gluon saturation on the back-to-back peak. In this talk, I will present the computation of the direct photon-quark production in DIS within the Color Glass Condensate Effective Field Theory. We find that this process depends only on the dipole gluon transverse momentum distribution. We use these results to provide the first numerical estimates for direct photon-quark azimuthal correlations. We observe a systematic suppression and broadening pattern of the back-to-back peak as the saturation scale is increased by replacing proton targets with gold nuclei. I will briefly comment on the feasibility of this measurement at the EIC. arXiv:2008.04372 [hep-ph]. To appear on JHEP.   

Live

Partons from the initial hard scatterings in high energy collisions cannot be directly observed, as they hadronize into a collimated spray of final state particles called jets. An extensive jet program has been proposed for the future Electron Ion Collider (EIC). Jets produced from deep inelastic scattering can be used as a powerful tool for studying energy loss and other cold-nuclear matter interactions, as well well as studying transverse-momentum-dependent parton distribution functions. Such measurements, however, depend on the jet reconstruction capabilities of the EIC detector. We study the charged jet reconstruction performance of an all silicon tracker design for the EIC using a full GEANT4 simulation in a 1.4T magnetic field. Events are generated using PYTHIA8 e+p collisions with a minimum $Q^2$ of 16 (GeV/$c^2)^2$. Jets are reconstructed using the anti-$k_\mathrm{T}$ jet finding algorithm with a resolution parameter of $R=1.0$ within the range of $|\eta_\mathrm{jet}| < 3.5$. We present the charged jet momentum response, as well as charged jet momentum and angular resolutions.   

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We explore the feasibility of the measurement of charm-jet cross sections in charged-current and neutral-current deep-inelastic scattering at the future Electron-Ion Collider. This channel provides clean sensitivity to the strangeness content of the nucleon in the high-$x$ region. We estimate charm-jet tagging performance with parametrized detector simulations. We study the feasibility of using jet substructure and particle identification in training a multivariate algorithm for charm-jet tagging. We show the expected sensitivity to various scenarios for strange parton distribution functions. We will motivate that this measurement as a key component future QCD global analyses, with implications for EIC detector designs and accelerator parameters. Part of this work is summarized in arXiv:2006.12520 (https://arxiv.org/abs/2006.12520).   

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We perform a comprehensive new Monte Carlo analysis of high-energy lepton-lepton, lepton-hadron and hadron-hadron scattering data to simultaneously determine parton distribution functions (PDFs) in the proton and parton to hadron fragmentation functions (FFs). The analysis includes all available semi-inclusive deep-inelastic scattering and single-inclusive $e^+ e^-$ annihilation data for pions, kaons and unidentified charged hadrons, which allows the flavor dependence of the fragmentation functions to be constrained. Employing a new multi-step fitting strategy and more flexible parametrizations for both PDFs and FFs, we assess the impact of different data sets on sea quark densities, and confirm the previously observed suppression of the strange quark distribution.   

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We calculate the photon-jet production cross section in proton-nucleus collisions extending the previous calculations, done in the small $x$ (low $p_t$) limit, to high $x$. This allows one to investigate the disappearance and re-appearance of the away side peak in azimuthal angular correlations from low to high $p_t$ as well as the forward-backward rapidity correlations.   

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The measurement of heavy hadron production cross-sections provides powerful tests on QCD models, at both perturbative and non-perturbative levels. Heavy hadron production involves the production of heavy quarks, and their subsequent hadronization into heavy hadrons. The first step can be calculated with perturbative QCD, while the latter is nonperturbative and its mechanism is not fully understood. There are many theories to describe hadron productions, such as the Color Singlet Model (CSM), or nonrelativistic QCD model for the J/psi production, polarization and the fragmentation approach or the complete order approach for B$_{\mathrm{c}}^{\mathrm{+}}$ production. However, current models cannot describe all experiment measurements well. This talk will present highlights from recent LHCb measurements, including the production of the heavy quarkonia and the fraction of B hadrons in the LHCb acceptance region (2\textless eta\textless 5) at different proton-proton collision energies. With these measurements, many theoretical models are tested and the understanding of strong interactions are improved.