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Nuclear Theory·nucl-th

Tuesday·August 10, 2021

15 papers—8 primary·7 cross-listed

All15Primary8Cross-lists7
  1. 09

    [Submitted on 6 Aug 2021] (cross-list from hep-ph)

    Radiative corrections to semileptonic beta decays: Progress and challenges

    Chien-Yeah Seng🇩🇪

    We review some recent progress in the theory of electroweak radiative corrections in semileptonic decay processes. The resurrection of the so-called Sirlin's representation based on current algebra relations permits a clear separation between the perturbatively-calculable and incalculable pieces in the radiative corrections. The latter are expressed as compact hadronic matrix elements that allow systematic non-perturbative analysis such as dispersion relation and lattice QCD. This brings substantial improvements to the precision of the electroweak radiative corrections in semileptonic decays of pion, kaon, free neutron and nuclei that are important theory inputs in precision tests of the Standard Model. Unresolved issues and future prospects are discussed.

    Comments:
    Version accepted for publication
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2108.03279 [pdf]
    Particles(2021)·29 citations
  2. 10

    [Submitted on 6 Aug 2021] (cross-list from hep-ph)

    Unified formalism for electromagnetic and gravitational probes: densities

    Adam Freese🇺🇸 · Gerald A. Miller🇺🇸

    The use of light front coordinates allows a fully relativistic description of a hadron's spatial densities to be obtained. These densities must be two-dimensional and transverse to a chosen spatial direction. We explore their relationship to the three-dimensional, non-relativistic densities, with a focus on densities associated with the energy momentum tensor. The two-dimensional non-relativistic densities can be obtained from the light front densities through a non-relativistic limit, and can subsequently be transformed into three-dimensional non-relativistic densities through an inverse Abel transform. However, this operation is not invertible, and moreover the application of the inverse Abel transform to the light front densities does not produce a physically meaningful result. We additionally find that the Abel transforms of so-called Breit-frame densities generally differ significantly from the true light front densities. Numerical examples are provided to illustrate the various differences between the light front, Breit frame, and non-relativistic treatment of densities.

    Comments:
    19 pages, 5 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2108.03301 [pdf]
    PRD(2022)·65 citations
  3. 11

    [Submitted on 7 Aug 2021] (cross-list from physics.app-ph)

    A new production route of Gadolinium-148 for use in Radioisotope Thermoelectric Generators

    Ozan Artun

    The production of Gd-148 had challenges for available methods in the literature, such as its high cost and low production amount. Therefore, we recommended a new production route of Gd-148 on natural Sm and Eu targets via particle accelerators. For this aim, we calculated and simulated cross-section, activity, the yield of product, and integral yield curves for 21 different nuclear reaction processes under certain conditions. Based on the obtained results, we proposed the radioisotope Gd-148 to use Radioisotope Thermoelectric Generators for deep space and planetary explorations in spacecraft and space-probes as a suitable energy source, instead of Pu-238.

    Comments:
    13 pages, 5 figures, 1 Teble
    Subjects:
    physics.app-ph (physics.app-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2108.03430 [pdf]
    Appl.Radiat.Isot.(2022)·0 citations
  4. 12

    [Submitted on 8 Aug 2021] (cross-list from hep-ph)

    Quark Sivers Function at Small : Spin-Dependent Odderon and the Sub-Eikonal Evolution

    Yuri V. Kovchegov🇺🇸 · M. Gabriel Santiago🇺🇸

    We apply the formalism developed earlier for studying transverse momentum dependent parton distribution functions (TMDs) at small Bjorken to construct the small- asymptotics of the quark Sivers function. First, we explicitly construct the complete fundamental "polarized Wilson line" operator to sub-sub-eikonal order: this object can be used to study a variety of quark TMDs at small-. We then express the quark Sivers function in terms of dipole scattering amplitudes containing various components of the "polarized Wilson line" and show that the dominant (eikonal) term which contributes to the quark Sivers function at small is the spin-dependent odderon, confirming the recent results of Dong, Zheng and Zhou. Our conclusion is also similar to the case of the gluon Sivers function derived by Boer, Echevarria, Mulders and Zhou (see also the work by Szymanowski and Zhou). We also analyze the sub-eikonal corrections to the quark Sivers function using the constructed "polarized Wilson line" operator. We derive new small- evolution equations re-summing double-logarithmic powers of with the strong coupling constant. We solve the corresponding novel evolution equations in the large- limit, obtaining a sub-eikonal correction to the spin-dependent odderon contribution. We conclude that the quark Sivers function at small receives contributions from two terms and is given by \begin{align} f_{1 \: T}^{\perp \: q} (x, k_T^2) = C_O (x, k_T^2) \, \frac{1}{x} + C_1 (k_T^2) \, \left( \frac{1}{x} \right)^0 + \ldots \end{align} with the function varying slowly with and the ellipsis denoting the sub-asymptotic and sub-sub-eikonal (order-) corrections.

    Comments:
    41 pages, 11 figures, 1 table. Added new discussion paragraphs in section III.A and section IV, added a footnote in section IV, corrected typos, updated references. v3: Minor typos corrected, the sub-eikonal term in the asymptotics of the Sivers function is revised in the follow up paper, see footnote on page 23
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2108.03667 [pdf]
    JHEP(2021)·59 citations
  5. 13

    [Submitted on 8 Aug 2021] (cross-list from hep-ph)

    A general-mass scheme for prompt charm production at hadron colliders

    Keping Xie🇺🇸 · John M. Campbell🇺🇸 · Pavel M. Nadolsky🇺🇸

    In these proceedings, we apply the recently developed S-ACOT-MPS factorization scheme at the next-to-leading order to prompt charm production at hadron colliders. It provides a good agreement with experimental data on charm meson production measured by LHCb at 7 and 13 TeV. The low- data are on the margins of the theoretical error bands, emphasizing the importance of including contributions beyond the next-to-leading order.

    Comments:
    Submission to SciPost
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2108.03741 [pdf]
    SciPost Phys.Proc.(2022)·12 citations
  6. 14

    [Submitted on 9 Aug 2021] (cross-list from nucl-ex)

    Progress in Nuclear Astrophysics of East and Southeast Asia

    Azni Abdul Aziz🇲🇾 · Nor Sofiah Ahmad🇲🇾 · S. Ahn🇰🇷 · Wako Aoki🇯🇵 · Muruthujaya Bhuyan🇲🇾 · Ke-Jung Chen🇹🇼 · Gang Guo🇹🇼 · K. I. Hahn🇰🇷 · Toshitaka Kajino🇯🇵 · Hasan Abu Kassim🇲🇾 · D. Kim🇰🇷 · Shigeru Kubono🇯🇵 and 16 other authors

    Nuclear astrophysics is an interdisciplinary research field of nuclear physics and astrophysics, seeking for the answer to a question, how to understand the evolution of the Universe with the nuclear processes which we learn. We review the research activities of nuclear astrophysics in east and southeast Asia which includes astronomy, experimental and theoretical nuclear physics and astrophysics. Several hot topics such as the Li problems, critical nuclear reactions and properties in stars, properties of dense matter, r-process nucleosynthesis and -process nucleosynthesis are chosen and discussed in further details. Some future Asian facilities, together with physics perspectives, are introduced.

    Comments:
    49 pages, 10 figures, published in AAPPS (Association of Asia Pacific Physical Societies) Bulletin
    Subjects:
    Nuclear Experiment (nucl-ex); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    2108.03814 [pdf]
    AAPPS Bull.(2021)·6 citations
  7. 15

    [Submitted on 9 Aug 2021] (cross-list from hep-ph)

    Nucleon structure from basis light-front quantization

    Siqi Xu🇨🇳 · Chandan Mondal🇨🇳 · Jiangshan Lan🇨🇳 · Xingbo Zhao🇨🇳 · Yang Li🇨🇳 · James P. Vary🇺🇸

    We produce the light-front wave functions (LFWFs) of the nucleon from a basis light-front ap- proach in the leading Fock sector representation. We solve for the mass eigenstates from a light-front effective Hamiltonian, which includes a confining potential adopted from light-front holography in the transverse direction, a longitudinal confinement, and a one-gluon exchange interaction with fixed coupling. We then employ the LFWFs to obtain the electromagnetic and axial form factors, the par- ton distribution functions (PDFs) and the generalized parton distribution functions for the nucleon. The electromagnetic and axial form factors of the proton agree with the experimental data, whereas the neutron form factors deviate somewhat from the experiments in the low momentum transfer region. The unpolarized, the helicity, and the transversity valence quark PDFs, after QCD scale evolution, are fairly consistent with the global fits to the data at the relevant experimental scales. The helicity asymmetry for the down quark also agrees well with the measurements, however, the asymmetry for the up quark shows a deviation from the data, especially in the small x region. We also find that the tensor charge agrees well with the extracted data and the lattice QCD predictions, while the axial charge is somewhat outside the experimental error bar. The electromagnetic radii of the proton, the magnetic radius of the neutron, and the axial radius are in excellent agreement with the measurements, while the neutron charge radius deviates from experiment.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2108.03909 [pdf]
    PRD(2021)·93 citations

Affiliations

first authorsco-authorsvia INSPIRE