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Nuclear Theory·nucl-th

Tuesday·November 14, 2023

16 papers—8 primary·8 cross-listed

All16Primary8Cross-lists8
  1. 01

    [Submitted on 11 Nov 2023]

    Dilepton production at next-to-leading order and intermediate invariant-mass observables

    Jessica Churchill🇨🇦 · Lipei Du🇨🇦 · Charles Gale🇨🇦 · Greg Jackson🇺🇸 · Sangyong Jeon🇨🇦

    The thermal QCD dilepton production rate is calculated at next-to-leading order in the strong coupling and at finite baryon chemical potential. The two-loop virtual photon self-energy is evaluated using finite temperature field theory and combined consistently with the self-energy in the Landau-Pomeranchuk-Migdal regime. We present new results for a dense baryonic plasma. The rates are then integrated using (3+1)-dimensional fluid-dynamical simulations calibrated to reproduce hadronic experimental results obtained at RHIC at energies ranging from those of the Beam Energy Scan to GeV. We elaborate on the ability for dileptons to relay information about the plasma baryonic content and temperature.

    Comments:
    v1: 19 pages, 15 figures; v2: minor revision; v3: published version. Companion paper: Phys. Rev. Lett. 132, 172301 (2024) [arXiv:2311.06951]
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2311.06675 [pdf]
    PRC(2024)·40 citations
  2. 02

    [Submitted on 12 Nov 2023]

    Pion-sigma meson vortices in rotating systems

    D. N. Voskresensky🇷🇺

    Possibilities of the formation of the pion-sigma meson field vortices in a rotating empty vessel (in vacuum) and in the pion-sigma Bose-Einstein condensates at a dynamically fixed particle number are studied within the linear model at zero temperature. The charged and neutral complex field ansatze (models 1 and 2) are studied. First it is analysed, which of these configurations is energetically favorable in case of the system at rest. Then conditions are found, at which a chiral field storm can arise in a rotating empty vessel. In the model 1 an important role played by the electric field is demonstrated. Its appearance may allow for formation of a supervortex (vortex with a large angular momentum) in case of the empty vessel rotating with an overcritical angular velocity. Influence of magnetic field is also studied. Field configurations in presence and absence of the meson self-interaction are found in both models. Then it is shown that description of the charged (in model 1) and neutral (in model 2) rotating pion-sigma Bose-Einstein condensates is analogous to that for the Bose-Einstein condensates in cold atomic gases. Various field configurations such as vortex lines, rings and spirals are discussed. Conditions for existence of the rigid-body rotation of the vortex lattice are then analysed. Observational effects for vortex fields in rotating vessels, energetic heavy-ion collisions and in rotating superheavy nuclei and nuclearites are discussed.

    Comments:
    21 pages, some misprints are corrected, accepted to PRD
    Subjects:
    Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2311.06804 [pdf]
    PRD(2024)·7 citations
  3. 03

    [Submitted on 12 Nov 2023]

    Cluster properties of heavy nuclei predicted with the Barcelona-Catania-Paris-Madrid energy density functional

    Samuel A. Giuliani · Luis M. Robledo

    We study the cluster emission properties of 224Ra and 238Pu employing the Barcelona-Catania-Paris-Madrid (BCPM) energy density functional (EDF). Starting from two-dimensional potential energy surfaces, coexisting fission paths are identified. A fission valley located at large octupole deformations, corresponding to a highly-asymmetric mass distribution, is found in both nuclei. As the corresponding fragments are dominated by the presence of 208Pb, we can relate this fission path to the emergence of cluster emission. Using the octupole moment as collective degree of freedom, we compute the cluster decay half-lives and study the impact of collective inertias, pairing strength and collective zero-point energy. The agreement with experimental data resembles the results obtained for spontaneous fission half-lives, indicating the capability of BCPM to consistently describe a large variety of fission phenomena, including cluster emission.

    Comments:
    12 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2311.06822 [pdf]
    EPJA(2023)·6 citations
  4. 04

    [Submitted on 12 Nov 2023]

    Virtual Photons Shed Light on the Early Temperature of Dense QCD Matter

    Jessica Churchill🇨🇦 · Lipei Du🇨🇦 · Charles Gale🇨🇦 · Greg Jackson🇺🇸 · Sangyong Jeon🇨🇦

    Dileptons produced during heavy-ion collisions represent a unique probe of the QCD phase diagram, and convey information about the state of the strongly interacting system at the moment their preceding off-shell photon is created. In this study, we compute thermal dilepton yields from Au+Au collisions performed at different beam energies, employing a (3+1)-dimensional dynamic framework combined with emission rates accurate at next-to-leading order in perturbation theory and which include baryon chemical potential dependencies. By comparing the effective temperature extracted from the thermal dilepton invariant mass spectrum with the average temperature of the fluid, we offer a robust quantitative validation of dileptons as effective probe of the early quark-gluon plasma stage.

    Comments:
    v1: 6+2 pages, 4+2 figures; v2: refs added, a table added in the Supplemental Material. Companion paper: arXiv:2311.06675
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2311.06951 [pdf]
    PRL(2024)·38 citations
  5. 05

    [Submitted on 13 Nov 2023]

    Optimal colliding energy for the synthesis of superheavy element =119

    Avazbek Nasirov (1 and 2) · Bakhodir Kayumov (3 and 2) ((1) Joint Institute for Nuclear Research, Dubna, Russia, (2) Institute of Nuclear Physics, Tashkent, Uzbekistan, (3) School of Humanities and Natural Sciences, New Uzbekistan University, Tashkent, Uzbekistan)

    The evaporation residue (ER) cross section of 3n and 4n channels related to the synthesis of superheavy element (SHE) with the charge number in the V+Cm reaction has been calculated by the dinuclear system (DNS) model as a sum of the partial cross sections of the corresponding channels. The angular momentum distribution of the compound nucleus is estimated by the dynamical trajectory calculations of the capture probability which is considered as the DNS formation probability. The fusion probability decreases by the increase of the DNS angular momentum due to its influence on the intrinsic fusion barrier . The range of the orientation angle of the axial symmetry axis of the deformed target nucleus Cm is favorable for the formation of the compound nucleus. The fusion probability decreases at around since the number of the partial waves contributing to the capture decreases. Therefore, it is important to calculate the capture cross section dynamically. The 4n channel cross section of the SHE synthesis is larger than the 3n channel cross section maximum value of the ER cross section is 12.3 fb at =232 MeV.

    Comments:
    9 pages, 8 figures, 3 tables
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2311.07145 [pdf]
    PRC(2024)·17 citations
  6. 06

    [Submitted on 13 Nov 2023]

    Quantal effect on the opening angle distribution between the fission fragment's spins

    Guillaume Scamps🇺🇸

    Background: Several approaches are currently trying to understand the generation of angular momentum in the fission fragments. The microscopic TDDFT and statistical FREYA lead to different predictions concerning the opening angle distribution formed between the two spins in particular at 0 and 180 degrees. Purpose: This letter aims to investigate how the geometry and the quantum nature of spins impact the distribution of opening angles to understand what leads to different model predictions. Method: Various assumptions of K distribution (K=0, isotropic, isotropic with total K=0, and from TDFFT) are investigated in a quantum approach. These distributions are then compared to the classical limit using the Clebsch-Gordan coefficients in the limit of approaches zero. Results: It is shown that in all the schematic scenario the quantal distribution of opening angle lead to the expected behavior in the classical limit. The model shows that the quantal nature of the spins prevents the population of opening angles close to 0 and 180 degrees. The difference in opening angle in the 2D and isotropic 3D distribution is discussed and it is shown that the realistic TDFFT opening angle distribution presents an intermediate behavior between the two cases. Conclusions: The last comparison reveals two key differences between the two models' predictions: the quantal spins' nature in TDDFT and the assumption of zero K values in FREYA.

    Comments:
    4 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
    arXiv:
    2311.07182 [pdf]
    PRC(2024)·12 citations
  7. 07

    [Submitted on 13 Nov 2023]

    Hydrodynamic theories for a system of weakly self-interacting classical ultra-relativistic scalar particles: causality and stability

    Caio V. P. de Brito🇧🇷 · Gabriel S. Rocha🇺🇸 · Gabriel S. Denicol🇧🇷

    We investigate the causality and stability of three different relativistic dissipative fluid-dynamical formulations emerging from a system of classical, ultra-relativistic scalar particles self-interacting via a quartic potential. For this particular interaction, all transport coefficients of Navier-Stokes, Bemfica-Disconzi-Noronha-Kovtun and second-order transient theories can be computed in analytical form. We first show that Navier-Stokes theory is acausal and unstable regardless of the matching conditions. On the other hand, BDNK theory can be linearly causal and stable for a particular set of matching choices that does not contain the so-called exotic Eckart prescription. In particular, using the Liénard-Chipart criterion, we obtain a set of sufficient conditions that guarantee the stability of the theory. Last, second-order transient hydrodynamic theory in Landau matching is shown to be linearly causal and stable.

    Comments:
    21 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
    arXiv:
    2311.07272 [pdf]
    PRD(2024)·10 citations
  8. 08

    [Submitted on 13 Nov 2023]

    Phase Transition Study meets Machine Learning

    Yu-Gang Ma🇨🇳 · Long-Gang Pang🇨🇳 · Rui Wang🇨🇳 · Kai Zhou🇩🇪

    In recent years, machine learning (ML) techniques have emerged as powerful tools for studying many-body complex systems, and encompassing phase transitions in various domains of physics. This mini review provides a concise yet comprehensive examination of the advancements achieved in applying ML to investigate phase transitions, with a primary focus on those involved in nuclear matter studies.

    Comments:
    arXiv admin note: text overlap with arXiv:2303.06752
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2311.07274 [pdf]
    Chin.Phys.Lett.(2023)·57 citations

Affiliations

first authorsco-authorsvia INSPIRE