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Nuclear Theory·nucl-th

Wednesday·August 28, 2024

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 01

    [Submitted on 26 Aug 2024]

    Tunneling half-lives in macroscopic-microscopic picture

    Samyak Jain · A. Bhagwat

    Tunneling half lives are obtained in a minimalistic deformation picture of nuclear decays. As widely documented in other deformation models, one finds that the effective mass of the nucleus changes with the deformation parameter. However, contrary to the approach used in literature, a position-dependant mass potentially makes using WKB tunneling probabilities unreliable for estimating nuclear lifetimes. We instead use a new approach, a combination of the Transmission Matrix and WKB methods, to estimate tunneling probabilities. Because of the simplistic nature of the model, the calculated lifetimes are not accurate, however, the relative trends in the lifetimes of isotopes of individual nuclei are found to be consistent. Using this, we develop an empirical scaling to obtain the actual half-lives, and find the primary scaling parameter to have remarkably consistent values for all nuclei considered. The new tunneling method proposed here, which produces very different probabilities as compared to the usual WKB approach, is another key result of this work, and can be utilized for arbitrary potentials and mass variations.

    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2408.14570 [pdf]
    0 citations
  2. 02

    [Submitted on 26 Aug 2024]

    Two-Body Triton Photodisintegration and Wigner-SU(4) Symmetry

    Xincheng Lin · Jared Vanasse

    We calculate the two-body triton photodisintegration cross section as a function of photon energy to next-to-next-to leading order (NNLO) in pionless effective field theory (EFT()) and show good agreement with experiment. In addition we calculate the polarization asymmetry in cold neutron-deuteron capture to NNLO in EFT(), in agreement with the experimental value of [M. W. Konijnenberg et al. in Phys. Lett. B 205, 215 (1988)]. We also assess the dependence of on different fits of the two-nucleon magnetic currents. Finally, we consider the impact of Wigner-SU(4) symmetry and demonstrate that starting from the Wigner-SU(4) symmetric limit and including perturbative corrections to the breaking of Wigner-SU(4) symmetry does a good job of describing two-body triton photodisintegration.

    Comments:
    40 pages, 6 figure; Published version
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2408.14602 [pdf]
    PRC(2025)·5 citations
  3. 03

    [Submitted on 27 Aug 2024]

    Interrelation between -Ca Atom Spectra and Nuclear Density Profiles

    Kenta Yoshimura · Shunsuke Yasunaga · Daisuke Jido · Junko Yamagata-Sekihara · Satoru Hirenzaki

    This work studies -Ca atom spectra in light of the strong shifts and level widths, using the optical model with several types of parametric coefficients. The spectroscopic quantities are obtained as the eigenvalues of the Dirac equation, where the nuclear densities computed via nuclear Density Functional Theory and the effect of the anomalous magnetic moment are incorporated. The results indicate that the isovector term's contribution to the optical potential is crucial for explaining the systematical differences in the strong shifts between Ca and Ca. Furthermore, it is found that both the strong shifts and the level widths exhibit significant dependence on the nuclear density profiles. These findings provide critical insights into the nuclear structures, particularly in the context of Calcium isotopes, by offering a more comprehensive understanding of the underlying nuclear-hadron properties.

    Comments:
    11 pages, 4 figures, 12 tables, PTEP accepted ver
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2408.14760 [pdf]
    PTEP(2025)·4 citations
  4. 04

    [Submitted on 27 Aug 2024]

    De-excitations of highly excited B and N based on the GEMINI++ code

    Yujie Niu · Wan-Lei Guo · Miao He · Jun Su

    Nuclear de-excitations associated with neutrino-nucleus interactions and nucleon decays are playing an increasingly significant role in neutrino experiments. We explore the GEMINI++ code and estimate its ability to account for the de-excitation processes of highly excited B and N, which can be created in the liquid scintillator and water Cherenkov detectors respectively. It is found that GEMINI++ can not describe the nuclear experimental data of B and N well. To improve its performance for de-excitations of light nuclei, we modify GEMINI++ and then develop a code of GEMINI++4, which can give the best predictions compared with experimental measurements among some widely used statistical model codes.

    Comments:
    8 pages, 4 figures, 2 tables, accepted by PLB. It will match the final version, to appear in PLB
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2408.14955 [pdf]
    PLB(2025)·1 citation
  5. 05

    [Submitted on 27 Aug 2024]

    Sources of longitudinal flow decorrelations in high-energy nuclear collisions

    Jiangyong Jia🇺🇸 · Shengli Huang🇺🇸 · Chunjian Zhang🇺🇸 · Somadutta Bhatta🇺🇸

    The longitudinal structure of the quark-gluon plasma (QGP) consists of several components spanning various scales. However, its short-range features are often obscured by final-state non-flow correlations. Here, we introduce a data-driven approach to separate initial state structures from non-flow effects. The longitudinal structure is found having two distinct components: one that reflects the global twisted geometry of the QGP, and another that captures localized fluctuations in rapidity. The characteristics of this second component, contributing to short- and medium-range flow decorrelations, can be quantified by comparing collisions of nuclei with different shapes. This study represents the first successful attempt to disentangle long- and short-range flow decorrelations from non-flow backgrounds, providing new insights into the initial conditions of heavy-ion collisions.

    Comments:
    6 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2408.15006 [pdf]
    13 citations
  6. 06

    [Submitted on 27 Aug 2024]

    Polaronic neutron in dilute alpha matter: A -wave Bose polaron

    Hiroyuki Tajima · Hajime Moriya · Tomoya Naito · Wataru Horiuchi · Eiji Nakano · Kei Iida

    We theoretically investigate quasiparticle properties of a neutron immersed in an alpha condensate, which is one of the possible states of dilute symmetric nuclear matter. The resonant -wave neutron-alpha scattering, which plays a crucial role in forming halo nuclei, is considered. This system is similar to a Bose polaron near the -wave Feshbach resonance that can be realized in cold-atomic experiments. Calculating the self-energy within the field-theoretical approach, we give an analytical formula for the effective mass of a polaronic neutron as a function of alpha condensation density. Moreover, two adjacent neutrons in a medium, each of which behaves like a stable polaron having an enhanced effective mass, can form a bound dineutron, with the help of neutron-neutron attraction. This is in contrast to the case of the vacuum, where a dineutron is known to be unbound. Our result would be useful for understanding many-body physics in astrophysical environments as well as the formation of multi-nucleon clusters in neutron-halo nuclei.

    Comments:
    12 pages, 6 figures. Published version
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Atomic Physics (physics.atom-ph)
    arXiv:
    2408.15043 [pdf]
    PRC(2025)·2 citations
  7. 07

    [Submitted on 27 Aug 2024]

    Why do newer degrees of freedom appear in higher-order truncated hydrodynamic theory?

    Sukanya Mitra🇮🇳

    An exact derivation of relativistic hydrodynamics from an underlying microscopic theory has been shown to be an all-order theory. From the relativistic transport equation of kinetic theory, the full expressions of hydrodynamic viscous fluxes have been derived which turn out to include all orders of out-of-equilibrium derivative corrections. It has been shown, that for maintaining causality, it is imperative that the temporal derivatives must include all orders, which can be resummed in non-local, relaxation operator-like forms and finally `integrated in' introducing newer degrees of freedom. The theory can of course be truncated at any higher spatial orders, but the power over the the infinite temporal sum increases correspondingly such that the causality is respected. As a result, the theory truncated at any higher order of spatial gradient, requires newer degrees of freedom for each increasing order.

    Comments:
    5 pages, accepted for publication in Physics Letters B
    Subjects:
    Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    2408.15088 [pdf]
    PLB(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE