PaperPanorama

Nuclear Theory·nucl-th

Tuesday·October 15, 2024

16 papers8 primary·8 cross-listed

  1. 01

    [Submitted on 10 Oct 2024]

    Investigating the Bulk Properties of Charged Particles in Different Bins Using a Modified Tsallis Model

    Haifa I. Alrebdi🇸🇦 · Muhammad Ajaz🇵🇰 · Murad Badshah🇵🇰 · Muhammad Waqas🇨🇳 · Nourah A.M. Alsaif🇸🇦

    This paper presents a comprehensive analysis of the double-differential distributions of charged particles in twelve distinct pseudorapidity regions of equal width in collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV. Utilizing the modified Tsallis function with mean transverse flow velocity, our study demonstrates a very good agreement between experimental data and the model employed. The fit quality is consistently high across all ranges, as assessed by Data/Fit panels accompanying each plot. Extracted parameters, including kinetic freeze-out temperature (), transverse flow velocity (), non-extensivity parameter () and mean transverse momentum dependencies are shown on pseudorapidity () and collision energy (). , and exhibit a decreasing trend with increasing due to lower in energy transfer along high regions, while they show a heightened sensitivity to . increases with , indicating a closer thermal equilibrium in mid- particles. The paper also explores correlations among these parameters, emphasizing relationships between , , and . Our study provides valuable insights into the thermal and dynamic characteristics of high-energy proton-proton collisions, contributing to the broader understanding of the bulk properties of nuclear matter produced in these interactions.

    Comments:
    7 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2410.09110 [pdf]
    0 citations
  2. 02

    [Submitted on 11 Oct 2024]

    Learning from knockout reactions using a dispersive optical model

    M.C. Atkinson · W.H. Dickhoff

    We present the empirical dispersive optical model (DOM) as applied to direct nuclear reactions. The DOM links both scattering and bound-state experimental data through a dispersion relation which allows for fully-consistent, data-informed predictions for nuclei where such data exists. In particular, we review investigations of the electron-induced proton knockout reaction from both Ca and Ca in a distorted-wave impulse approximation (DWIA) utilizing the DOM for a fully-consistent description. Viewing these reactions through the lens of the DOM allows us to connect the documented quenching of spectroscopic factors with increased high-momentum proton content in neutron-rich nuclei. A similar DOM-DWIA description of the proton-induced knockout from Ca, however, does not currently fit in the consistent story of its electron-induced counterpart. With the main difference in the proton-induced case being the use of an effective proton-proton interaction, we suggest that a more sophisticated in-medium interaction would lead to consistent results.

    Comments:
    28 pages, 11 figures, 4 tables. arXiv admin note: substantial text overlap with arXiv:1808.08895; text overlap with arXiv:2408.16097
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.09287 [pdf]
    Front.in Phys.(2024)·1 citation
  3. 03

    [Submitted on 12 Oct 2024]

    Theoretical study on and correlation functions

    Asanosuke Jinno🇯🇵 · Yuki Kamiya🇩🇪 · Tetsuo Hyodo🇯🇵 · Akira Ohnishi🇯🇵

    We examine the - () and momentum correlation in high-energy collisions to further elucidate the properties of the hyperon-nucleon interactions. For the system, we compare potential models with different strengths at short range. We find that the difference among the models is visible in the momentum correlation from a small-size source. This indicates that the momentum correlation can constrain the property of the interaction at short range, which plays an essential role in dense nuclear matter. For the system, we employ the folding potential based on the lattice QCD interactions. The potential supports a Coulomb assisted bound state of in the channel, while the channel is unbound. To examine the sensitivity of the correlation function to the nature of the potential, we vary the potential strength simulating stronger and weaker interactions. The result of the correlation function clearly reflects the bound state nature in the correlation.

    Comments:
    13 pages, 4 figures, Proceedings of Hadron interactions with strangeness and charm, 26-28 Jun 2024
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.09390 [pdf]
    J.Subatomic Part.Cosmol.(2024)·2 citations
  4. 04

    [Submitted on 12 Oct 2024]

    Fission fragment distributions within time-dependent density functional theory

    Yun Huang · Xiang-Xiang Sun · Lu Guo

    A notable issue, the proper description of mass and charge distributions of fission fragments within nonadiabatic descriptions of fission dynamics, is investigated by performing double particle number projection on the outcomes of time-dependent Hartree-Fock (TDHF) simulation. The induced fission process of the benchmark nucleus 240Pu is studied. In the three-dimensional Cartesian coordinate without any symmetry restrictions, we get the static fission pathway from the two-dimensional potential energy surface, and then the fission dynamics from saddle to scission point are obtained using TDHF. We show that the charge numbers of primary heavy fragments from TDHF simulation strongly depend on the deformations of initial configurations via the two asymmetric fission channels, which can be distinguished according to the dynamical fission trajectories. The charge distribution of fission fragments is well reproduced using the double particle number projection technique. After applying the Gaussian kernel estimation based on the distribution from the double particle number projection technique, the mass distribution is also consistent with the experimental results. Besides, the results of the total kinetic energy of fission fragments are reasonably consistent with the experiments.

    Comments:
    8 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.09565 [pdf]
    EPJA(2024)·7 citations
  5. 05

    [Submitted on 12 Oct 2024]

    Role of the tensor force in induced fission of 240Pu

    Yun Huang · Xiang-Xiang Sun · Lu Guo

    Results: We find that the tensor force affects the height of fission barriers and the double-humped structure of fission path of 240Pu. On the PES, the fission valley becomes larger in the (Q20, Q30) plane, and the triaxial deformation is suppressed around the outer barrier after considering the tensor force. Incorporating the tensor force into the dynamical process enhances the difference in shape evolution between two asymmetric channels. More interestingly, the charge distribution from TDHF with double PNP calculations shows a strong odd-even effect after including the tensor force. In addition, the total mass and charge distributions of fission fragments show a slight shift towards larger asymmetry and are more consistent with the experiments when tensor components are included. We also find that the tensor force enhances energy gaps of the deformed shells for heavy fragments. Moreover, the TKEs of fragments are in accord with the experiments, and after incorporating the tensor force, we observe a higher concentration of the calculated TKEs for heavy fragments at Z = 52 and Z = 56. Conclusions: The tensor force plays a role in both static and dynamical processes in nuclear fission, improving the accuracy of theoretical descriptions within the current framework. Our calculations have shown that the fission-barrier height with SLy5t is closer to the empirical value than that of SLy5. Additionally, the inclusion of the tensor force not only manifests the odd-even effect in charge distribution but also improves the description of total mass and charge distributions.

    Comments:
    16 pages, 13 figures, Submitted to Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2410.09577 [pdf]
    PRC(2024)·8 citations
  6. 06

    [Submitted on 12 Oct 2024]

    On Two Nucleons Near Unitarity with Perturbative Pions

    Yu Ping Teng (U. of Wisconsin-Madison and George Washington University)🇺🇸 · Harald W. Griesshammer (George Washington U.)🇺🇸

    We explore the impact of perturbative pions on the Unitarity Expansion in the two-nucleon S-waves of Chiral Effective Field Theory at next-to-next-to leading order. Pion exchange explicitly breaks the nontrivial fixed point's universality and invariance under conformal and Wigner- spin-isospin transformations. This Chiral Effective Field Theory applies tothe Unitarity Window (45deg<delta(k)<135deg,) most relevant for low-energy nuclear systems. Its only LO scale is the scattering momentum; NLO adds only scattering length, effective range and non-iterated one-pion exchange (OPE); and N2LO only once-iterated OPE. Agreement in the 1S0 channel is very good. Apparent large discrepancies in the 3S1 channel at k>100MeV are remedied by taking only the central part of the pion's N2LO contribution. In contradistinction to the tensor part, it is invariant under Wigner-SU(4)symmetry and hence identical in 1S0 and 3S1. NLO pions are Wigner-invariant. Both channels describe PWAs and pole parameters well within mutually consistent quantitative theory uncertainty estimates. Pionic effects are small, even for k>mpi. Empirically determined breakdown scales agree well with MeV where iterated OPE is not suppressed. We therefore conjecture: The footprint of both scale invariance and Wigner-symmetry in the Unitarity Expansion shows persistence,i.e. both dominate even for k=mpi and are more relevant than chiral symmetry,so that the tensor/Wigner-SU(4) symmetry-breaking part of OPE does not enter before N3LO. We also discuss the potential relevance of entanglement power and possible resolution of a conflict with the strength of the tensor interaction in the large-Nc expansion.

    Comments:
    55 pages LaTeX2e (pdflatex) with 13 figures as 13 .pdf files via includegraphics. Results and conclusions unchanged. Major restructuring, streamlining, clarifications, condensations for readability. Added discussion of fixed point and interplay with entanglement, and with large-Nc limit. Final: cosmetic changes, revisions of entanglement subsection, text-identical with version published by EPJA
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2410.09653 [pdf]
    EPJA(2025)·6 citations
  7. 07

    [Submitted on 14 Oct 2024]

    Universal laws for nuclear contacts

    Tongqi Liang · Dong Bai · Zhongzhou Ren

    The nuclear contact characterizes the nucleon-nucleon pairs in close proximity and serves as an important tool for studying the short-range correlations (SRCs) within atomic nuclei. While they have been extracted for selected nuclei, the investigation of their behavior across the nuclear chart remains limited. Very recently, Yankovich, Pazy, and Barnea have proposed a set of universal laws (YPB laws) to describe the correlation between nuclear contacts and nuclear radii and tested their laws for a small number of nuclei by using the Woods-Saxon mean-field model~[R.\ Yankovich, E.\ Pazy, and N.\ Barnea, arXiv:2407.15068 (2021)]. In this Letter, we extend their study to a majority part of the chart of nuclides within the framework of the Skyrme Hartree-Fock-Bogolyubov model, which incorporates several essential beyond-mean-field features and offers a more accurate description of the bulk properties of atomic nuclei. Our results suggest that the YPB laws hold as a good approximation for different nuclear mass regions, with minor deviations attributed to, e.g., isospin-breaking effects. Our work lays a firm foundation for future applications of the YPB laws in finite nuclei and provides new evidence for the long-range nature of the relative abundance of short-range pairs.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.10202 [pdf]
    PLB(2025)·4 citations
  8. 08

    [Submitted on 14 Oct 2024]

    Relaxation of particle-hole type excitation in a Fermi system within the diffusion approximation of kinetic theory for the case of constant diffusion and drift coefficients

    Sergiy V. Lukyanov

    The time evolution of the distribution function for a particle-hole excitation in a Fermi system was calculated using the direct numerical solution of a nonlinear diffusion equation in momentum space. A phenomenological expression for calculating the relaxation time of such an excitation to its equilibrium value has been proposed. It is shown that the relaxation time is dependent on both the excitation energy and the mass number.

    Comments:
    15 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.10492 [pdf]
    Acta Phys.Polon.B(2025)·2 citations
  9. 09

    [Submitted on 11 Oct 2024] (cross-list from hep-ph)

    Consistent chiral limit in on-shell renormalized quark-meson model with ChPT scaling

    Vivek Kumar Tiwari🇮🇳

    Chiral perturbation theory (ChPT) predicted scaling of the pion,~kaon decay constants and has been used in the renormalized flavor quark-meson (RQM) model,~to find a consistent path to chiral limit as the meson masses approach zero.~The left side of the Columbia plot is generated free from any ambiguity or heuiristic adjustment in the model parameter fixing away from the physical point. The on-shell renormalization of parameters and consistent treatment of the divergent quark one-loop vacuum fluctuations in the RQM model,~make the axial anomaly significantly stronger and the light (strange) explicit chiral symmetry breaking strength becomes weaker by a small (relatively large) amount.~The first order chiral transition region in the and planes of Columbia plot,~increases due to the above novel features of the RQM model.~Comparing the softening effect of quark one-loop vacuum fluctuation on the chiral transition,~it looks overestimated in a recent functional renormalization group study.

    Comments:
    6-7 pages 4 Figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2410.08461 [pdf]
    PRD(2025)·5 citations
  10. 10

    [Submitted on 10 Oct 2024] (cross-list from hep-ph)

    Rotation induced color confinement

    Guojun Huang🇨🇳 · Shile Chen🇨🇳 · Yin Jiang🇨🇳 · Jiaxing Zhao🇩🇪 · Pengfei Zhuang🇨🇳

    The rotation effect on the QCD properties is an open question. We study the dynamic gluon mass in a dense QCD matter, the rotation is introduced by taking a covariant transformation between the flat and curved spaces. The law of causality which restricts the rotation strength of the system is carefully considered in the calculation. we find that the rotation effect is not monotonous. Overall, it behaves like an anti-screening effect, reflecting in the decreasing gluon mass, but the strength changes with the rotation. For a QCD matter with low baryon density, the screening effect in the flat space can be completely canceled by the rotation, and gluons are confined in a strongly rotating matter. When the rotation is extremely high, the matter approaches to a weakly interacting gas.

    Comments:
    9 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2410.09108 [pdf]
    PLB(2025)·0 citations
  11. 11

    [Submitted on 11 Oct 2024] (cross-list from nucl-ex)

    Measurement of Quadrupole Deformation using E and ME Transitions in Heavy Isotopes in the Mass Range of

    Prajwal MohanMurthy · Lixin Qin · Jeff A. Winger

    The measurement of a permanent electric dipole moment (EDM) in atoms is crucial for understanding the origins of CP-violation. However, accurate interpretation of the EDM in systems involving deformed isotopes requires the characterization of their deformation. While nuclear deformation is indicated in various structure models, there is substantial mutual disagreement between the theoretical models or between theoretical models and experimental values. Nuclear E transitions allow access to quantify quadrupole deformation, but these transitions are often mixed with M transitions. Both E and M transitions are well characterized by Weisskopf estimates, which rely on a single-particle approximation, but deviate due to collective nuclear deformations. Previously, Weisskopf estimates were only available for the mass range , and in this work we have extended the Weisskopf estimates of both E and M transition lifetimes to the mass range of . We comprehensively studied the deviation of E and ME transition lifetimes from the newly established Weisskopf estimates in candidate isotopes, by comparing the transition lifetimes of the candidate isotopes to their nearest even-even counterparts, whose E transition strengths are very well understood. Estimates of collective nuclear quadrupole deformation in of these isotopes were thus obtained, either from E or ME transition lifetimes. In cases they were obtained from both types of transitions independently, and are mutually consistent, as well as following the trends established in theory. We thereby identify the isotopes Fr, Ra, Ac and Pa, where EDM measurements are foreseen and information on nuclear deformation is needed, for which no measurement of nuclear quadrupole deformation has been made.

    Comments:
    Proceedings of The 10th International Conference on Quarks and Nuclear Physics, (QNP 2024) Jul 8-12, 2024, Barcelona, Spain. Abs \#ID: 8. 18 pages, 3 figures, 3 tables. Ver. 4: Fixed units
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2410.09272 [pdf]
    PoS(2025)·0 citations
  12. 12

    [Submitted on 12 Oct 2024] (cross-list from hep-ph)

    Chiral symmetry breaking, chiral partners, and the and in medium

    Su Houng Lee🇰🇷

    We clarify the concept of chiral partners. For a vector meson, the isospin-zero and hypercharge-zero state in the flavor octet mixes with the flavor singlet state. Since the flavor singlet vector meson does not have a chiral partner, the mixed and mesons will not have chiral partners. This means that even when chiral symmetry is restored, these mesons will not become degenerate with their corresponding parity partners. On the other hand, the and mesons are chiral partners, and both have widths smaller than 100 MeV. Therefore, we emphasize that studying these mesons in environments where chiral symmetry is restored is particularly important for understanding the effect of chiral symmetry restoration on chiral partners and their masses.

    Comments:
    9 pages, Proceeding for the Reimi Workshop "Hadron interactions with strangeness and charm", held in Jeju on June 27-28, 2024
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2410.09364 [pdf]
    J.Subatomic Part.Cosmol.(2024)·2 citations
  13. 13

    [Submitted on 12 Oct 2024] (cross-list from hep-ph)

    Strong decay widths of S- and P-wave singly-, doubly- and triply-heavy charm and bottom baryons

    Emmanuel Ortiz-Pacheco · Roelof Bijker

    We present a study of two-body decay widths of heavy baryons into another heavy baryon and a light pseudoscalar meson in the framework of the non-relativistic quark model in combination with the elementary emission model for the strong couplings. The present study includes the decays of 1S- and 1P-wave baryons with one, two or three heavy quarks, either charm (c) or bottom (b). The relative partial widths are given by the appropriate flavor SU(3) isoscalar factors. The flavor, spin and orbital contributions are discussed explicitly as well as selection rules for forbidden decays. The total widths are compared with the available experimental data as well as with other theoretical studies. The calculated widths of singly-heavy baryons are found to be in reasonable agreement with the observed widths. The decay widths of doubly-heavy baryons are suppressed with respect to those of the singly-heavy baryons by the ratios of the quark masses appearing in the orbital contributions.

    Comments:
    16 pages, 4 figures, 8 tables, submitted to Physical Review D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2410.09622 [pdf]
    9 citations
  14. 14

    [Submitted on 12 Oct 2024] (cross-list from quant-ph)

    General theory of constructing potential with bound states in the continuum

    Mao Kurino · Kazuo Takayanagi

    We present a general theory of potentials that support bound states at positive energies (bound states in the continuum). On the theoretical side, we prove that, for systems described by nonlocal potentials of the form , bound states at positive energies are as common as those at negative energies. At the same time, we show that a local potential of the form rarely supports a positive energy bound state. On the practical side, we show how to construct a (naturally nonlocal) potential which supports an arbitrary normalizable state at an arbitrary positive energy. We demonstrate our theory with numerical examples both in momentum and coordinate spaces with emphasis on the important role played by nonlocal potentials. Finally, we discuss how to observe bound states at positive energies, and where to search for nonlocal potentials which may support them.

    Comments:
    32 pages, 22 figures
    Subjects:
    Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
    arXiv:
    2410.09647 [pdf]
    PTEP(2024)·0 citations
  15. 15

    [Submitted on 14 Oct 2024] (cross-list from hep-ph)

    Pentaquarks in a dynamical coupled-channel approach of reaction

    Xu Zhang🇨🇳

    We construct a dynamical coupled-channel approach to photon-induced production to search for the trace of the pentaquarks . In this approach, the considered open-charm intermediate states are and . Scattering amplitude involving , and interactions is calculated from solving a set of coupled-channel integral equations. The coupled-channel interaction potentials are generated from one-boson-exchange. The pentaquarks are dynamically generated from the coupled-channel interactions. Moreover, the background contributions to the signals are assumed to be the Pomeron exchange and exchange. The predicted total and differential cross sections of photoproduction are within the range of the data from the GlueX and - experiments. It is found that the exchange plays a crucial role for determining the very near threshold cross section. The total cross section gets enhanced due to the open-charm state rescattering in the , and production regions, and is of order 1 nb.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2410.10154 [pdf]
    EPJC(2025)·10 citations
  16. 16

    [Submitted on 14 Oct 2024] (cross-list from hep-ph)

    Correlations and fluctuations in a magnetized PNJL model with and without inverse magnetic catalysis effect

    Shijun Mao🇨🇳

    The correlation and quadratic fluctuations of baryon number , electric charge and temperature are investigated in a two-flavor Polyakov loop extended Nambu-Jona-Lasinio (PNJL) model at finite temperature and magnetic field. The inverse magnetic catalysis (IMC) effect is introduced through the magnetic field dependent parameters or , and we make comparison of the results in the cases with and without IMC effect. With nonvanishing magnetic field, the correlation and fluctuations increase with temperature, and then show the peak around the pseudocritical temperatures of chiral restoration and deconfinement phase transitions in the cases with and without the IMC effect. The correlation and fluctuations along the phase transition line under external magnetic field are characterized by the scaled correlation and scaled fluctuations at the pseudocritical temperature of chiral restoration phase transition. , and increase with magnetic fields, and the inclusion of IMC effect leads to some enhancement in their values. However, is altered by the IMC effect. Without IMC effect, slightly increases and then decreases with magnetic fields. Taking into account of the IMC effect by , monotonically increases with magnetic fields, and by , it is a nonmonotonic function of magnetic field.

    Comments:
    8 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2410.10217 [pdf]
    CPC(2025)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE