Nuclear Theory·nucl-th

Thursday·November 21, 2024

15 papers—7 primary·8 cross-listed

01
[Submitted on 19 Nov 2024]
Intertwined Quantum Phase Transitions in Bose and Bose-Fermi Systems
A. Leviatan
Pronounced structural changes within individual configurations (Type I QPT), superimposed on an abrupt crossing of these configurations (Type II QPT), define the notion of intertwined quantum phase transitions (QPTs). We discuss and present evidence for such a scenario in finite Bose and Bose-Fermi systems. The analysis is based on algebraic models with explicit configuration mixing, where the two types of QPTs describe shape-phase transitions in-between different dynamical symmetries and shape-coexistence with crossing.
Comments:
18 pages, 13 figures, talk at Symposium "Symmetries in Science XIX", July 30 - August 4, 2023, Bregenz, Austria
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)
arXiv:
2411.12816 [pdf]
J.Phys.Conf.Ser.(2024)·0 citations
02
[Submitted on 19 Nov 2024]
Untangling the interplay of the Equation-of-State and the Collision Term towards the generation of Directed and Elliptic Flow at intermediate energies
Tom Reichert🇩🇪 · Jörg Aichelin🇩🇪
The mechanism for generating directed and elliptic flow in heavy-ion collisions is investigated and quantified for the SIS18 and SIS100 energy regimes. The observed negative elliptic flow $v_{2}$ , at midrapidity has been explained either via (in-plane) shadowing or via (out-of-plane) squeeze-out. To settle this question, we employ the Ultra-relativistic Quantum Molecular Dynamics model (UrQMD) to calculate Au+Au collisions at E $_{lab} = 0.6 A$ GeV, E $_{lab} = 1.23 A$ GeV and $s_{NN} = 3.0$ GeV using a hard Skyrme type Equation-of-State to calculate the time evolution and generation of directed flow and elliptic flow. We quantitatively distinguish the impact of collisions and of the potential on $v_{1}$ and $v_{2}$ during the evolution of the system. These calculations reveal that in this energy regime the generation of $v_{1}$ and $v_{2}$ follows from a highly intricate interplay of different processes and is created late, after the system has reached its highest density and has created a matter bridge between projectile and target remnant, which later breaks. Initially, we find a strong out-of-plane pressure. Then follows a strong stopping and the built up of an in-plane pressure. The $v_{2}$ , created by both processes, compensate to a large extend. The finally observed $v_{2}$ is caused by the potential, reflects the freeze-out geometry and can neither be associated to squeeze-out nor to shadowing. The results are highly relevant for experiments at GSI, RHIC-FXT and the upcoming FAIR facility, but also for experiments at FRIB, and strengthens understanding on the Equation-of-State at large baryon densities.
Comments:
19 pages, 18 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2411.12908 [pdf]
PRC(2025)·12 citations
03
[Submitted on 20 Nov 2024]
Examining the potential synthesis of new elements with $^{294}$ Og
Shuai Zhang · Gao-Chan Yong · J. L. Rodríguez-Sánchez · J. Cugnon
In the relentless pursuit of expanding the periodic table, the discovery of element 119 remains elusive, despite two decades of dedicated research efforts. The traditional fusion-evaporation approach, although fruitful in the past, now appears to be approaching its operational limits. This scenario sets the stage for considering innovative methodologies essential for further advancements in the field of superheavy elements. Here, we introduce a pioneering strategy aimed at synthesizing element 119 by adapting and extending the nuclear reaction processes previously successful in producing element $^{294}$ Og. This involved the fusion of $^{48}$ Ca and $^{249}$ Cf. Building on this, our novel approach incorporates an additional reactive target -- specifically, hydrogen -- positioned strategically behind the $^{249}$ Cf. This configuration is designed to facilitate an immediate secondary reaction of the nascent $^{294}$ Og with hydrogen, potentially forging new pathways to element 119. Preliminary insights also suggest that employing isotopes like deuterium or helium-3 as targets may not only enhance the production rates of element 119 but might also pave the way for the synthesis of even heavier elements, extending up to elements 120 and 121. We delve into the technicalities and feasibility of employing a dual-target method using a $^{48}$ Ca beam, exploring new horizons in the quest for the superheavy unknown.
Comments:
5 pages, 4 figures, submitted
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2411.13095 [pdf]
0 citations
04
[Submitted on 20 Nov 2024]
Constraining the Phase-Transition EoS using the Energy Dependence of Directed Flow
Zhi-Min Wu🇨🇳 · Gao-Chan Yong🇨🇳 · Qingfeng Li🇨🇳
We propose a hybrid equation of state (VDF+MIT EoS) to describe the hadron-quark phase transition in dense nuclear matter. By coupling this EoS with the AMPT-HC transport model and comparing to recent experimental data on proton and $Λ$ directed flow $v_{1}$ , we constrain the transition to likely occur near $5 ρ_{0}$ -- $6 ρ_{0}$ , ruling out transitions below $3 ρ_{0}$ . Furthermore, we introduce the energy derivative of the mid-rapidity $v_{1}$ slope, $d (d v_{1} / d y) / d (s_{N N})$ , as a weakly model-dependent observable. Its zero crossing provides a direct signature of the phase transition critical point, offering a new tool for mapping the QCD phase diagram in future experiments.
Comments:
10 pages, 7 figures, 1 table, to PRD
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2411.13107 [pdf]
PRD(2026)·1 citation
05
[Submitted on 20 Nov 2024]
Exploring hadron-quark phase transition in heavy-ion collisions using particle emission ratios in heavy and light reaction systems
Xun Zhu🇨🇳 · Gao-Chan Yong🇨🇳
Based on the AMPT model, which incorporates both hadronic and quark degrees of freedom, we studied the productions of lambda, kaon, proton, and pion in reaction systems $^{40}$ Ca+ $^{40}$ Ca, $^{48}$ Ca+ $^{48}$ Ca, and $^{197}$ Au+ $^{197}$ Au. It is found that the ratios of identical particle emissions from heavy and light reaction systems, especially the emission ratios of strange particles $Λ^{0}$ or K $^{+}$ in heavy and light reaction systems, are highly sensitive to the hadron-quark phase transition in heavy-ion collisions. Detailed explanations and validations of these results are given.
Comments:
5 pages, 5 figures, accepted by PLB
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2411.13110 [pdf]
PLB(2025)·1 citation
06
[Submitted on 20 Nov 2024]
Validity of Brink Axel Hypothesis for calculations of allowed stellar weak rates of heavy nuclei
Fakeha Farooq · Jameel-Un Nabi · Ramoona Shehzadi
The knowledge of beta decay transitional probabilities and GamowTeller (GT) strength functions from highly excited states of nuclides is of particular importance for applications to astrophysical network calculations of nucleosynthesis in explosive stellar events. These quantities are challenging to achieve from measurements or computations using various nuclear models. Due to unavailability of feasible alternatives, many theoretical studies often rely on the Brink Axel (BA) hypothesis, that is, the response of strength functions depends merely on the transition energy of the parent nuclear ground state and is independent of the underlying details of the parent state, for the calculation of stellar rates. BA hypothesis has been used in many applications from nuclear structure determination to nucleosynthesis yield in the astrophysical matter.
Comments:
29 Pages, 8Figures 5 Tables
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2411.13123 [pdf]
Phys.Scripta(2023)·2 citations
07
[Submitted on 20 Nov 2024]
Novel features of asymmetric nuclear matter from terrestrial experiments and astrophysical observations of neutron stars
Tsuyoshi Miyatsu🇰🇷 · Myung-Ki Cheoun🇰🇷 · Kyungsik Kim🇰🇷 · Koichi Saito🇯🇵
The accurate measurement of neutron skin thickness of $^{208}$ Pb by the PREX Collaboration suggests a large value of the nuclear symmetry energy slope parameter, $L$ , whereas the smaller $L$ is preferred to account for the small neutron-star radii from NICER observations. To resolve this discrepancy between nuclear experiments and astrophysical observations, new effective interactions have been developed using relativistic mean-field models with the isoscalar- and isovector-meson mixing. We investigate the effects of $δ$ -nucleon coupling and $σ$ -- $δ$ mixing on the ground-state properties of finite nuclei, as well as the characteristics of isospin-asymmetric nuclear matter and neutron stars. Additionally, we explore the role of the quartic $ρ$ -meson self-interaction in dense nuclear matter to mitigate the stiff equation of state for neutron stars resulting from the large $δ$ -nucleon coupling. It is found that the nuclear symmetry energy undergoes a sudden softening at approximately twice the saturation density of nuclear matter, taking into account the PREX-2 result, the recent NICER observation of PSR J0437 $-$ 4715, and the binary neutron star merger, GW170817.
Comments:
36 pages, 12 figures, 6 tables, matching to the version accepted for publication as a REVIEW article in Frontiers in Physics
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2411.13210 [pdf]
Front.in Phys.(2024)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

Intertwined Quantum Phase Transitions in Bose and Bose-Fermi Systems

Untangling the interplay of the Equation-of-State and the Collision Term towards the generation of Directed and Elliptic Flow at intermediate energies

Examining the potential synthesis of new elements with 294Og

Constraining the Phase-Transition EoS using the Energy Dependence of Directed Flow

Exploring hadron-quark phase transition in heavy-ion collisions using particle emission ratios in heavy and light reaction systems

Validity of Brink Axel Hypothesis for calculations of allowed stellar weak rates of heavy nuclei

Novel features of asymmetric nuclear matter from terrestrial experiments and astrophysical observations of neutron stars

Affiliations

Examining the potential synthesis of new elements with $^{294}$ Og