Nuclear Theory·nucl-th

Tuesday·January 10, 2023

16 papers—9 primary·7 cross-listed

01
Hadron-quark phase transition in neutron star by combining the relativistic Brueckner-Hartree-Fock theory and Dyson-Schwinger equation approach
Pianpian Qin🇨🇳 · Zhan Bai🇨🇳 · Sibo Wang🇨🇳 · Chencan Wang🇨🇳 · Si-xue Qin🇨🇳
Starting from the relativistic Brueckner-Hartree-Fock theory for nuclear matter and the Dyson-Schwinger equation approach for quark matter, the possible hadron-quark phase transition in the interior of a neutron star is explored. The first-order phase transition and crossover are studied by performing the Maxwell construction and three-window construction respectively. The mass-radius relation and the tidal deformability of the hybrid star are calculated and compared to the joint mass-radius observation of a neutron star and the constraints from gravitational wave detection. For the Maxwell construction, no stable quark core is found in the interior of a neutron star. For the three-window construction, the parameters of the smooth interpolation function are chosen in such a way to keep the thermodynamic stability and lead to a moderate crossover density region. To support a two-solar-mass neutron star under the three-window construction, the effective width of medium screening effects in quark matter should be around $0.35$ GeV.
nucl-thPRD(2023)·12 citations
02
Can a pure neutron state of matter exist?
F. R. Xu
A short discussion on possible multineutron resonances.
nucl-thnucl-exSci.Bull.(2022)·2 citations
03
Temperature and density effects on the two-nucleon momentum correlation function from excited single nuclei
Ting-Ting Wang · Yu-Gang Ma · De-Qing Fang · Huan-Ling Liu
Two-nucleon momentum correlation functions are investigated for different single thermal sources at given initial temperature $(T)$ and density $(ρ)$ . To this end, the space-time evolutions of various single excited nuclei at $T$ $= 1 - 20$ $M e V$ and $ρ$ = 0.2 - 1.2 $ρ_{0}$ are simulated by using the thermal isospin-dependent quantum molecular dynamics $(T h I QM D)$ model. Momentum correlation functions of identical proton-pairs ( $C_{pp} (q)$ ) or neutron-pairs ( $C_{nn} (q)$ ) at small relative momenta are calculated by $L e d ni c k y ˊ$ and $L y u b os hi t z$ analytical method. The results illustrate that $C_{pp} (q)$ and $C_{nn} (q)$ are sensitive to the source size ( $A$ ) at lower $T$ or higher $ρ$ , but almost not at higher $T$ or lower $ρ$ . And the sensitivities become stronger for smaller source. Moreover, the $T$ , $ρ$ and $A$ dependencies of the Gaussian source radii are also extracted by fitting the two-proton momentum correlation functions, and the results are consistent with the above conclusions.
nucl-thPRC(2022)·8 citations
04
Directed flow and global polarization in Au+Au collisions across energies covered by the beam energy scan at RHIC
Ze-Fang Jiang🇨🇳 · Xiang-Yu Wu🇨🇳 · Shanshan Cao🇨🇳 · Ben-Wei Zhang🇨🇳
We study the directed flow of identified particles in Au+Au collisions at $s_{NN} = 7.7$ to 62.4 GeV. The Glauber model is extended to include both a tilted deformation of the QGP fireball with respect to the longitudinal direction and a non-zero longitudinal flow velocity gradient in the initial state. By combining this improved initial condition with a (3+1)-dimensional viscous hydrodynamic model calculation, we obtain a satisfactory description of the transverse momentum spectra and the rapidity dependent directed flow coefficient of different hadron species. Our calculation indicates the sensitivity of the hadron directed flow, especially its splitting between protons and antiprotons, to both the initial geometry and the initial longitudinal flow velocity. Therefore, the combination of directed flow of different hadrons can provide a tight constraint on the initial condition of nuclear matter created in heavy-ion collisions. The initial condition extracted from the directed flow is further tested with the global polarization of $Λ$ and $Λ ˉ$ within the same theoretical framework, where we obtain a reasonable description of these hyperon polarization observed at different collision energies at RHIC.
nucl-thhep-phnucl-exPRC(2023)·19 citations
05
Impacts of momentum dependent interaction, symmetry energy and near-threshold $N N \to N Δ$ cross sections on isospin sensitive flow and pion observables
Yangyang Liu🇨🇳 · Yingxun Zhang🇨🇳 · Junping Yang🇨🇳 · Yongjia Wang🇨🇳 · Qingfeng Li🇨🇳 · Zhuxia Li🇨🇳
Based on the ultra-relativistic quantum molecular dynamics (UrQMD) model, the impacts of momentum dependent interaction, symmetry energy and near-threshold $N N \to N Δ$ cross sections on isospin sensitive collective flow and pion observables are investigated. Our results confirm that the elliptic flow of neutrons and charged particles, i.e. $v_{2}^{n}$ and $v_{2}^{c h}$ , are sensitive to the strength of momentum dependence interaction and the elliptic flow ratio, i.e., $v_{2}^{n} / v_{2}^{c h}$ , is sensitive to the stiffness of symmetry energy. For describing the pion multiplicity near the threshold energy, accurate $N N \to N Δ$ cross sections are crucial. With the updated momentum dependent interaction and $N N \to N Δ$ cross sections in UrQMD model, seven observables, such as directed flow and elliptic flow of neutrons and charged particles, the elliptic flow ratio of neutrons to charged particles, charged pion multiplicity and its ratio $π^{-} / π^{+}$ , can be well described by the parameter sets with the slope of symmetry energy from 5 MeV to 70 MeV. To describe the constraints of symmetry energy at the densities probed by the collective flow and pion observables, the named characteristic density is investigated and used. Our analysis found that the flow characteristic density is around 1.2 $ρ_{0}$ and pion characteristic density is around 1.5 $ρ_{0}$ , and we got the constrains of symmetry energy at characteristic densities are $S (1.2 ρ_{0}) = 34 \pm 4$ MeV and $S (1.5 ρ_{0}) = 36 \pm 8$ MeV. These results are consistent with previous analysis by using pion and flow observable with different transport models, and demonstrate a reasonable description of symmetry energy constraint should be presented at the characteristic density of isospin sensitive observables.
nucl-thnucl-ex2 citations
06
Probing the structural evolution along the fission path in the superheavy nucleus $^{256}$ Sg
Ting-Ting Li · Hua-Lei Wang · Zhen-Zhen Zhang · Min-Liang Liu
The evolution of structure property along the fission path in the superheavy nucleus $^{256}$ Sg is predicted through the multi-dimensional potential-energy(or Routhian)-surface calculations,in which the phenomenological deformed Woods-Saxon potential is adopted. Calculated nuclear deformations and fission barriers for $_{106}^{256}$ Sg $_{150}$ and its neighbors, e.g., $^{258, 260}$ Sg, $^{254}$ Rf and $^{252}$ No are presented and compared with other theoretical results. A series of energy maps and curves are provided and used to evaluate the corresponding shape-instability properties, especially in the directions of triaxial $γ$ and different hexadecapole deformations (e.g., $α_{40}$ , $α_{42}$ and $α_{44}$ ). It is found that the triaxial deformation may help the nucleus bypass the first fission-barrier of the axial case. After the first minimum in the nuclear energy surface, the fission pathway of the nucleus can be affected by $γ$ and hexadecapole deformation degrees of freedom. In addition, microscopic single-particle structure, pairing and Coriolis effects are briefly investigated and discussed.
nucl-thIndian J.Phys.(2023)·2 citations
07
Analysis of realistic and empirical multipole interactions for shell-model calculations
Kamila Sieja🇫🇷
We perform analysis of realistic nucleon-nucleon interactions, as well as of empirically-corrected interactions, fitted to reproduce in detail the spectroscopic data in p and sd shells. We focus on the multipole part of the interactions, contrary to previous studies of that type which focused on monopole parts. We analyze how the different parts of the NN force (tensor, spin-orbit and central) contribute to the leading multipoles of the interaction and how do they renormalize in medium. We show that the leading coherent terms of the realistic and effective interactions are dominated by the central component as expected from their schematic operator structure. Convergence and cutoff dependence of multipole Hamiltonians is also discussed.
nucl-th0 citations
08
Particle-number fluctuations near the critical point of nuclear matter
A.G. Magner · S.N. Fedotkin · U.V. Grygoriev
The equation of state with quantum statistics corrections is used for particle number fluctuations $ω$ of isotopically symmetric nuclear matter with interparticle van der Waals and Skyrme local density interactions. The fluctuations, $ω \propto 1/ K$ , are analytically derived through the isothermal incompressibility $K$ at first order over a small quantum-statistics parameter. Our approximate analytical results appear to be in good agreement with the results of accurate numerical calculations. These results are also close to those obtained by using more accurate Tolman and Rowlinson expansions of the incompressibility $K$ near the critical point. A more general formula for fluctuations $ω$ , improved at the critical point, was obtained for a finite particle-number average $⟨ N ⟩$ by neglecting, for simplicity, small quantum statistics effects. It is shown that for a large dimensionless parameter, $α \propto K^{2} ⟨ N ⟩ / K^{''}$ , where $K^{''}$ is the second derivative of the incompressibility $K$ as function of the average particle density $n$ , far from the critical point ( $α ≫ 1$ ), one finds the traditional asymptote, $ω \propto 1/ K$ , for the fluctuations $ω$ . For a small parameter, $α ≪ 1$ , near the critical point, where $K = 0$ and $α = 0$ , one obtains another asymptote of $ω$ . These fluctuations, having a maximum near the critical point as function of the average density $n$ , for finite values of $⟨ N ⟩$ are finite and relatively small, in contrast to the results of the traditional calculations.
nucl-thPRC(2023)·0 citations
09
Impact of nuclear shape fluctuations in high-energy heavy ion collisions
Aman Dimri🇺🇸 · Somadutta Bhatta🇺🇸 · Jiangyong Jia🇺🇸
The shape of atomic nuclei is often interpreted to possess a quadrupole deformation that fluctuates around some average profile. We investigate the impact of nuclear shape fluctuations on the initial state geometry in heavy ion collisions, particularly its eccentricity $ε_{2}$ and inverse size $d_{⊥}$ , which can be related to the elliptic and radial flow in the final state. The fluctuation in overall quadrupole deformation enhances the variances and modifies the skewness and kurtosis of the $ε_{2}$ and $d_{⊥}$ in a controllable manner. The fluctuation in triaxiality reduces the difference between prolate and oblate shape for any observable, whose values, in the large fluctuation limit, approach those obtained in collisions of rigid triaxial nuclei. The method to disentangle the mean and variance of the quadrupole deformation is discussed.
nucl-thhep-phnucl-exEPJA(2023)·29 citations
10
Simulations of momentum correlation functions of light (anti)nuclei in relativistic heavy-ion collisions at $s_{N N}$ = 39 GeV
Ting-Ting Wang🇨🇳 · Yu-Gang Ma🇨🇳 · Song Zhang🇨🇳
Momentum correlation functions of light (anti)nuclei formed by the coalescence mechanism of (anti)nucleons are calculated for several central heavy-ion collision systems, namely $_{5}^{10} B +_{5}^{10} B$ , $_{8}^{16} O +_{8}^{16} O$ , $_{20}^{40} Ca +_{20}^{40} Ca$ as well as $_{79}^{197} Au +_{79}^{197} Au$ in different centralities at center of mass energy $s_{N N}$ = 39 GeV within the framework of A Multi-Phase Transport (AMPT) model complemented by the Lednick $y ˊ$ and Lyuboshitz analytical method. Momentum correlation functions for identical or nonidentical light (anti)nuclei are constructed and analyzed for the above collision systems. The Au + Au results demonstrate that emission of light (anti)nuclei occurs from a source with smaller space extent in more peripheral collisions. The effect of system-size on the momentum correlation functions of identical or nonidentical light (anti)nuclei is also explored by several collision system in central collisions. The results indicate that the emission source-size of light (anti)nuclei pairs deduced from their momentum correlation functions and system-size is self-consistent. Momentum correlation functions of nonidentical light nuclei pairs gated on velocity are applied to infer the average emission sequence of them. The results illustrate that protons are emitted in average on a similar time scale with neutrons but earlier than deuterons or tritons in the small relative momentum region. In addition, larger interval of the average emission order among them is exhibited for smaller collision systems or at more peripheral collisions.
↳ hep-phnucl-thPRC(2023)·13 citations
11
De Haas - van Alphen Effect under Rotation
Shu-Yun Yang🇨🇳 · Ren-Da Dong🇨🇳 · Defu Hou🇨🇳 · Hai-Cang Ren🇨🇳
We explored the interplay between magnetic field and rotation in the de Hass - van Alphen oscillation. The effect is found to be reduced because of the re-weighting of different states within the same Landau level by rotation energy. The implications of our results on high energy physics and condensed matter physics are speculated.
↳ hep-phnucl-thPRD(2023)·5 citations
12
David Maurice Brink, 20 July 1930 - 8 March 2021
C. V. Sukumar · A. Bonaccorso
David Brink was one of the leading theoretical nuclear physicists of his generation. He made major contributions to the study of all aspects of nuclear physics embracing nuclear structure, nuclear scattering, and nuclear instability. His wide ranging interests and interactions with theorists and experimentalists alike helped him in providing both theoretical analysis and interpretations and suggesting experiments. He had the gift of visualising complex problems in simple terms and provided clear analysis of the underlying processes. He was an expert on the use of semi-classical methods which provided an intuitively clear picture of complex phenomena. His research work and books are characterised by scientific clarity, transparency, and depth. David possessed outstanding skills in mathematical computation, and he was an expert on special functions, group theory, and the Feynman path integral method. David had many research students and collaborated with a large number of scientists from across the world, for whom he was a source of scientific and human inspiration and admiration. His most fundamental belief was that research was a means of trying to discover and understand the beauties of Nature and explain them in simple terms to others. His absolute belief in the value of truth and his unselfish and generous attitude in sharing knowledge makes him an outstanding figure in contemporary Nuclear Physics.
↳ physics.hist-phnucl-exnucl-thBiographical Memoirs of Fellows of the Ro…·0 citations
13
Neutron stars in the context of $f$ ( $T$ , $T$ ) gravity
Clésio E. Mota · Luis C. N. Santos · Franciele M. da Silva · Cesar V. Flores · Iarley P. Lobo · Valdir B. Bezerra
In this work, we investigate the existence of neutron stars (NS) in the framework of $f$ ( $T$ , $T$ ) gravity, where $T$ is the torsion tensor and $T$ is the trace of the energy-momentum tensor. The hydrostatic equilibrium equations are obtained, however, with $p$ and $ρ$ quantities passed on by effective quantities $p ˉ$ and $ρ ˉ$ , whose mass-radius diagrams are obtained using modern equations of state (EoS) of nuclear matter derived from relativistic mean field models and compared with the ones computed by the Tolman-Oppenheimer-Volkoff (TOV) equations. Substantial changes in the mass-radius profiles of NS are obtained even for small changes in the free parameter of this modified theory. The results indicate that the use of $f$ ( $T$ , $T$ ) gravity in the study of NS provides good results for the masses and radii of some important astrophysical objects, as for example, the low-mass X-ray binary (LMXB) NGC 6397 and the pulsar of millisecond PSR J0740+6620. In addition, radii results inferred from the Lead Radius EXperiment (PREX-2) can also be described for certain parameter values.
↳ astro-ph.HEgr-qcnucl-thUniverse(2023)·8 citations
14
Synergy between NP and HEP research goals and efforts in fundamental symmetries and interactions
Tanmoy Bhattacharya🇺🇸 · Rajan Gupta🇺🇸 · Kate Scholberg🇺🇸
The aim of this white paper is to highlight several areas for which the Department of Energy's Office of Nuclear Physics has primary stewardship or significant investment and expertise, and for which there is also significant interest and expertise within the HEP community. These areas of overlap offer exciting opportunities for collaboration.
↳ hep-phhep-lathep-thnucl-ex+10 citations
15
Popcorn transitions and approach to conformality in homogeneous holographic nuclear matter
Jesús Cruz Rojas🇰🇷 · Tuna Demircik🇵🇱 · Matti Järvinen🇰🇷
We study cold and dense nuclear matter by using the gauge/gravity duality. To this end we use the Witten-Sakai-Sugimoto model and the V-QCD models with an approach where the nuclear matter is taken to be spatially homogeneous. We focus on the ''popcorn'' transitions, which are phase transitions in the nuclear matter phases induced by changes in the layer structure of the configuration on the gravity side. We demonstrate that the equation of state for the homogeneous nuclear matter becomes approximately conformal at high densities, and compare our results to other approaches.
↳ hep-thnucl-thSymmetry(2023)·13 citations
16
Quasi-equilibrium configurations of binary systems of dark matter admixed neutron stars
Hannes R. Rüter · Violetta Sagun · Wolfgang Tichy · Tim Dietrich
Using an adapted version of the SGRID code, we construct for the first time consistent quasi-equilibrium configurations for a binary system consisting of two neutron stars in which each is admixed with dark matter. The stars are modelled as a system of two non-interacting fluids minimally coupled to gravity. For the fluid representing baryonic matter the SLy equation of state is used, whereas the second fluid, which corresponds to dark matter, is described using the equation of state of a degenerate Fermi gas. We consider two different scenarios for the distribution of the dark matter. In the first scenario the dark matter is confined to the core of the star, whereas in the second scenario the dark matter extends beyond the surface of the baryonic matter, forming a halo around the baryonic star. The presence of dark matter alters the star's reaction to the companion's tidal forces, which we investigate in terms of the coordinate deformation and mass shedding parameters. The constructed quasi-equilibrium configurations mark the first step towards consistent numerical-relativity simulations of dark matter admixed neutron star binaries.
↳ gr-qcastro-ph.HEnucl-thPRD(2023)·36 citations

Affiliations

first authorsco-authorsvia INSPIRE