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Nuclear Theory·nucl-th

Thursday·August 31, 2023

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 01

    [Submitted on 29 Aug 2023]

    Interfacing Electron and Neutrino Quasielastic Scattering Cross Sections with the Spectral Function in GENIE

    Minerba Betancourt🇺🇸 · Steven Gardiner🇺🇸 · Noemi Rocco🇺🇸 · Noah Steinberg🇺🇸

    Progress in neutrino-nucleus cross section models is being driven by the need for highly accurate predictions for the neutrino oscillation community. These sophisticated models are being developed within a microscopic description of the nucleus with the goal of encompassing all reaction modes relevant for the accelerator neutrino program. The disconnect between these microscopic models and the event generators that will be used in the next generation of experiments represents a critical obstacle that must be overcome in order to precisely measure the neutrino oscillation parameters. To this end we have developed a Fortran wrapper for lepton-nucleus quasielastic (QE) scattering within the GENIE event generator as a proof of principle, with the broader goal of creating an efficient pipeline for incorporating advanced theoretical models in event generators. As a demonstration of this interface, we have implemented the Spectral Function model into GENIE, offering a more complete description of the nuclear ground state, as well as the ability to provide quantifiable theoretical uncertainties. We validate this implementation and compare its predictions against data and against QE models already available in GENIE.

    Comments:
    10 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2308.15524 [pdf]
    PRD(2023)·4 citations
  2. 02

    [Submitted on 29 Aug 2023]

    Excited Hadron Channels in Hadronization

    Rainer J. Fries🇺🇸 · Jacob Purcell🇺🇸 · Michael Kordell II🇺🇸 · Che-Ming Ko🇺🇸

    The proper treatment of hadronic resonances plays an important role in many aspects of heavy ion collisions. This is expected to be the case also for hadronization, due to the large degeneracies of excited states, and the abundant production of hadrons from their decays. We first show how a comprehensive treatment of excited meson states can be incorporated into quark recombination, and in extension, into Hybrid Hadronization. We then discuss the quantum mechanics of forming excited states, utilizing the Wigner distribution functions of angular momentum eigenstates of isotropic 3-D harmonic oscillators. We further describe how resonance decays can be handled, based on a set of minimal assumptions, by creating an extension of hadron decays in PYTHIA 8. Finally, we present first results by simulating collisions using PYTHIA and Hybrid Hadronization with excited mesons up to orbital angular momentum and radial quantum number 2. We find that states up to are produced profusely by quark recombination.

    Comments:
    6 pages, 3 figures; submitted to Proceedings of Science
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2308.15608 [pdf]
    PoS(2024)·1 citation
  3. 03

    [Submitted on 29 Aug 2023]

    Ab initio uncertainty quantification of neutrinoless double-beta decay in Ge

    A. Belley🇨🇦 · J. M. Yao🇨🇳 · B. Bally🇫🇷 · J. Pitcher🇨🇦 · J. Engel🇺🇸 · H. Hergert🇺🇸 · J. D. Holt🇨🇦 · T. Miyagi🇩🇪 · T. R. Rodriguez🇪🇸 · A. M. Romero🇪🇸 · S. R. Stroberg🇺🇸 · X. Zhang🇨🇳

    The observation of neutrinoless double-beta () decay would offer proof of lepton number violation, demonstrating that neutrinos are Majorana particles, while also helping us understand why there is more matter than antimatter in the Universe. If the decay is driven by the exchange of the three known light neutrinos, a discovery would, in addition, link the observed decay rate to the neutrino mass scale through a theoretical quantity known as the nuclear matrix element (NME). Accurate values of the NMEs for all nuclei considered for use in experiments are therefore crucial for designing and interpreting those experiments. Here, we report the first comprehensive ab initio uncertainty quantification of the -decay NME, in the key nucleus Ge. Our method employs nuclear strong and weak interactions derived within chiral effective field theory and recently developed many-body emulators. Our result, with a conservative treatment of uncertainty, is an NME of , which, together with the best-existing half-life sensitivity and phase-space factor, sets an upper limit for effective neutrino mass of meV. The result is important for designing next-generation germanium detectors aiming to cover the entire inverted hierarchy region of neutrino masses.

    Comments:
    7 pages, 1 table, and 2 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2308.15634 [pdf]
    PRL(2024)·87 citations
  4. 04

    [Submitted on 30 Aug 2023]

    A Neural Network Approach for Orienting Heavy-Ion Collision Events

    Zu-Xing Yang🇯🇵 · Xiao-Hua Fan🇨🇳 · Zhi-Pan Li🇨🇳 · Shunji Nishimura🇯🇵

    A convolutional neural network-based classifier is elaborated to retrace the initial orientation of deformed nucleus-nucleus collisions by integrating multiple typical experimental observables. The isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model is employed to generate data for random orientations of ultra-central uranium-uranium collisions at . Statistically, the data-driven polarization scheme is essentially accomplished via the classifier, whose distinct categories filter out specific orientation-biased collision events. This will advance the deformed nucleus-based studies on nuclear symmetry energy, neutron skin, etc.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2308.15796 [pdf]
    PLB(2024)·9 citations
  5. 05

    [Submitted on 30 Aug 2023]

    The EMC effect for few-nucleon bound systems in Light-Front Hamiltonian Dynamics

    Filippo Fornetti🇮🇹 · Emanuele Pace🇮🇹 · Matteo Rinaldi🇮🇹 · Giovanni Salmè🇮🇹 · Sergio Scopetta🇮🇹 · Michele Viviani🇮🇹

    The light-front formalism for a covariant description of the European Muon Collaboration (EMC) effect, already applied to He, is formally extended to any nucleus, and used for actually calculating the H and He cases. The realistic and accurate nuclear description of few-nucleon bound systems, obtained with both phenomenological and chiral potentials, has been properly combined with the Poincare' covariance and macroscopic locality, automatically satisfying both number of particles and momentum sum rule. While retaining the on-mass-shell nucleon structure functions, one is then able to predict a sizable EMC effect for He, as already observed for He. Moreover, the impact on the EMC effect of both i) the short-range correlations, such as those generated by modern nuclear interactions, and ii) the ratio between the neutron and proton structure functions has been studied. The short-range correlations generated by retaining only the standard nuclear degrees of freedom act on the depth of the minimum in the EMC ratio, while the uncertainties linked to the ratio of neutron to proton structure functions are found to be very small. These light-front results facilitates ascribing deviations from experimental data due to genuine QCD effects, not included in a standard nuclear description, and initiating unbiased investigations.

    Comments:
    13 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2308.15925 [pdf]
    PLB(2024)·8 citations
  6. 06

    [Submitted on 30 Aug 2023]

    Description of multinucleon transfer mechanism for and reactions in quantal transport approach

    M. Arik · S. Ayik · O. Yilmaz · A. S. Umar

    This work aims to show that the quantal diffusion approach based on the stochastic mean field (SMF) theory is capable of explaining the reaction dynamics observed in MNT reactions. Primary product mass distributions in Ca+Pu reaction at E 203.2 MeV and Kr+Pt reaction at E 324.2 MeV are calculated and compared with the available experimental data.

    Comments:
    10 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2308.16027 [pdf]
    PRC(2023)·11 citations
  7. 07

    [Submitted on 30 Aug 2023]

    Lepton-induced reactions on nuclei in a wide kinematical regime

    U. Mosel🇩🇪 · K. Gallmeister🇩🇪

    Inclusive differential cross sections for various and reactions are analyzed within the GiBUU theoretical framework and code. The treatment of electron-nuclus reactions has been significantly improved by implementing a parametrized description of electron-nucleon interactions for a nucleon. Using the momentum of a nucleon inside the Fermi sea the electron-nucleon cross sections are then Lorentz-boosted to obtain the electron structure functions for nuclei. The neutrino structure functions are obtained from the ones for electrons by a transformation that involves the axial formfactors and kinematical factors that account for the difference of vector and axial currents. Special emphasis is put on analyzing data from various different experiments in different neutrino energy regimes with one and the same theoretical input.

    Comments:
    Model description extended. Figs. 9 - 13 replaced because of an error in the plot-routine. Results otherwise unchanged
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2308.16161 [pdf]
    PRD(2024)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE