Nuclear Theory·nucl-th

Friday·January 20, 2023

12 papers—7 primary·5 cross-listed

01
[Submitted on 18 Jan 2023]
Flow Distribution Analysis as A Probe of Nuclei Deformity
Hadi Mehrabpour🇩🇪 · S. M. A. Tabatabaee🇮🇷
We study the flow harmonic distribution in deformed nuclei. To do this, we use the standard Gram-Charlier method to find the higher-order correction to the well-known Bessel-Gaussian distribution. We find that, apart from the necessity of including a shift parameter $v ˉ_{n}$ , the modified flow distribution describes the flow distribution of quadrupole and octupole deformation accurately. Using the shifted radial distribution, arising from this method, we scrutinize the effect of deformation on flow distribution. Assuming a linear relation between observables of spherical and deformed collisions, $O_{D} = O_{S} + (\sum_{m = 2} a_{k, m} β_{m})^{2 k}$ , for events with a fixed centrality, we compare the flow distribution of deformed and spherical nuclei. We also propose a way to measure $v ˉ_{2}$ in asymmetric nuclei collisions.
Comments:
11 pages and 11 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2301.07770 [pdf]
PRC(2023)·7 citations
02
[Submitted on 19 Jan 2023]
Bayesian inference of nucleus resonance and neutron skin
Jun Xu🇨🇳
In this proceeding, we have presented some highlight results on the constraints of the nuclear matter equation of state (EOS) from the data of nucleus resonance and neutron-skin thickness using the Bayesian approach based on the Skyrme-Hartree-Fock model and its extension. Typically, we have discussed the anti-correlation and positive correlation between the slope parameter and the value of the symmetry energy at the saturation density under the constraint of, respectively, the neutron-skin thickness and the isovector giant dipole resonance. We have shown that the Bayesian analysis can help to find a compromise for the ``PREXII puzzle'' and the ``soft Tin puzzle". We have further illustrated the possible modifications on the constraints of lower-order EOS parameters as well as the relevant correlation when higher-order EOS parameters are incorporated as independent variables. For a given model and parameter space, the Bayesian approach serves as a good analysis tool suitable for multi-messengers versus multi-variables, and is helpful for constraining quantitatively the model parameters as well as their correlations.
Comments:
10 pages, 8 figures, proceeding of the workshop on applications of machine learning in nuclear physics and nuclear data, Rui Chang, Jiangxi province, China, Aug. 5-7 th, 2022
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2301.07884 [pdf]
Atomic Energ.Sci.Technol.(2023)·1 citation
03
[Submitted on 19 Jan 2023]
Measuring deformed neutron skin with free spectator nucleons in relativistic heavy-ion collisions
Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳
The neutron skin in deformed nuclei is generally not uniformly distributed but has an angular distribution, depending on both the spin-dependent nuclear interaction and the nuclear symmetry energy. To extract the information of the deformed neutron skin, we have explored the possibility of using free spectator nucleons in central tip-tip and body-body collisions at top RHIC energy with four typical deformed nuclei. The density distributions of neutrons and protons are consistently obtained from the Skyrme-Hartree-Fock-Bogolyubov calculation, and the angular distribution of the neutron skin can be varied by adjusting the strength of the nuclear spin-orbit coupling. With the information of spectator nucleons obtained based on a Monte-Carlo Glauber model, the free spectator nucleons are generated from a multifragmentation process. By investigating the results from different systems and with different collision configurations, we found that although it is difficult to probe the deformed neutron skin in $^{96}$ Zr and $^{238}$ U by their collisions, it is promising to extract the polar angular distributions of the neutron skin in $^{96}$ Ru and $^{197}$ Au by comparing the yield ratios of free spectator neutrons to protons in their central tip-tip and body-body collisions. The proposed observables can be measured by dedicated zero-degree calorimeters in heavy-ion collision experiments that have been carried out in recent years by RHIC.
Comments:
7 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
arXiv:
2301.07893 [pdf]
PLB(2023)·23 citations
04
[Submitted on 19 Jan 2023]
Bayesian inference of neutron-star observables based on effective nuclear interactions
Jia Zhou🇨🇳 · Jun Xu🇨🇳 · Panagiota Papakonstantinou🇰🇷
Based on the Skyrme-Hartree-Fock model (SHF) as well as its extension (the Korea-IBS-Daegu-SKKU (KIDS) model) and the relativistic mean-field (RMF) model, we have studied the constraints on the parameters of the nuclear matter equation of state (EOS) from adopted astrophysical observables using a Bayesian approach. While the masses and radii of neutron stars generally favors a stiff isoscalar EOS and a moderately soft nuclear symmetry energy, model dependence on the constraints is observed and mostly originates from the incorporation of higher-order EOS parameters and difference between relativistic and non-relativistic models. At twice saturation density, the value of the symmetry energy is constrained to be $4 8_{- 11}^{+ 15}$ MeV in the standard SHF model, $4 8_{- 15}^{+ 8}$ MeV in the KIDS model, and $4 8_{- 6}^{+ 5}$ MeV in the RMF model, around their maximum {\it a posteriori} values within $68%$ confidence intervals. Our study helps to obtain a robust constraint on nuclear matter EOS, and meanwhile, to understand the model dependence of the results.
Comments:
16 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2301.07904 [pdf]
PRC(2023)·25 citations
05
[Submitted on 19 Jan 2023]
Revisiting angular momentum conservation in transport simulations of intermediate-energy heavy-ion collisions
Rong-Jun Liu🇨🇳 · Jun Xu🇨🇳
Based on the well-calibrated IBUU transport model, we have studied the dynamical effect of incorporating rigorous angular momentum conservation in each collision of particles with homework setups. The constraint of the rigorous angular momentum conservation requires in-plane collisions and side jumps of particles after their collision. Since the option is not unique, we have compared two typical prescriptions with the original one. While the results depend quantitatively on the choice of the prescription, we found that the angular momentum conservation generally reduces local density fluctuations and thus the collision rate, and may have some influence on the density evolution, the collective flow, and even the pion production in transport simulations of intermediate-energy heavy-ion collisions.
Comments:
8 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2301.07907 [pdf]
Universe(2023)·3 citations
06
[Submitted on 19 Jan 2023]
Shear viscosity of nuclear matter in the spinodal region
Lei-Ming Hua🇨🇳 · Jun Xu🇨🇳
Based on IBUU simulations calibrated by previous efforts of the transport model evaluation project, we have studied the specific shear viscosity $η / s$ of nuclear matter in the spinodal region using the Green-Kubo method. With the momentum-independent mean-field potential which reproduces reasonably well empirical nuclear matter properties and nuclear phase diagram, we have generated dynamically stable and thermalized nuclear cluster systems in a box with the periodic boundary condition. Extensive results of the $η / s$ at different average densities and temperatures in uniform and non-uniform systems are compared, and we found that the shear viscosity is smaller with nuclear clusters due to the enhanced correlation of the energy-momentum tensor and the stronger collision effect. The temperature dependence of the $η / s$ has a minimum only at low average densities of $ρ < 0.3 ρ_{0}$ . The present study serves as a rigorous baseline calculation of the $η / s$ in nuclear systems with clusters, and helps to understand the relation between the shear viscosity and the nuclear phase diagram.
Comments:
12 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2301.07922 [pdf]
PRC(2023)·3 citations
07
[Submitted on 19 Jan 2023]
Spanning the full range of neutron star properties within a microscopic description
Tuhin Malik🇵🇹 · Márcio Ferreira🇵🇹 · Milena Bastos Albino🇵🇹 · Constança Providência🇵🇹
The high-density behavior of nuclear matter is analyzed within a relativistic mean-field description with non-linear meson interactions. To assess the model parameters and their output, a Bayesian inference technique is used. The Bayesian setup is limited only by a few nuclear saturation properties, the neutron star maximum mass larger than 2 M $_{⊙}$ , and the low-density pure neutron matter equation of state (EOS) produced by an accurate N $^{3}$ LO calculation in chiral effective field theory. Depending on the strength of the non-linear scalar vector field contribution, we have found three distinct classes of EOSs, each one correlated to different star properties distributions. If the non-linear vector field contribution is absent, the gravitational maximum mass and the sound velocity at high densities are the greatest. However, it also gives the smallest speed of sound at densities below three times saturation density. On the other hand, models with the strongest non-linear vector field contribution predict the largest radii and tidal deformabilities for 1.4 M $_{⊙}$ stars, together with the smallest mass for the onset of the nucleonic direct Urca processes and the smallest central baryonic densities for the maximum mass configuration. These models have the largest speed of sound below three times saturation density, but the smallest at high densities, in particular, above four times saturation density the speed of sound decreases approaching approximately $0.4 c$ at the center of the maximum mass star. On the contrary, a weak non-linear vector contribution gives a monotonically increasing speed of sound. A 2.75 M $_{⊙}$ NS maximum mass was obtained in the tail of the posterior with a weak non-linear vector field interaction. We found that pQCD favors models with a large non-linear vector field contribution or hyperons.
Comments:
There are 17 pages, 16 figures (The typographical error in the supplemental update)
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2301.08169 [pdf]
PRD(2023)·67 citations
08
[Submitted on 18 Jan 2023] (cross-list from hep-ph)
Target mass corrections in lepton--nucleus DIS: theory and applications to nuclear PDFs
R. Ruiz🇵🇱 · K. F. Muzakka🇩🇪 · C. Leger🇫🇷 · P. Risse🇩🇪 · A. Accardi🇺🇸 · P. Duwentäster🇩🇪 · T. J. Hobbs🇺🇸 · T. Ježo🇩🇪 · C. Keppel🇺🇸 · M. Klasen🇩🇪 · K. Kovařík🇩🇪 · A. Kusina🇵🇱 and 5 other authors
Motivated by the wide range of kinematics covered by current and planned deep-inelastic scattering (DIS) facilities, we revisit the formalism, practical implementation, and numerical impact of target mass corrections (TMCs) for DIS on unpolarized nuclear targets. An important aspect is that we only use nuclear and later partonic degrees of freedom, carefully avoiding a picture of the nucleus in terms of nucleons. After establishing that formulae used for individual nucleon targets $(p, n)$ , derived in the Operator Product Expansion (OPE) formalism, are indeed applicable to nuclear targets, we rewrite expressions for nuclear TMCs in terms of \mbox{re-scaled} (or averaged) kinematic variables. As a consequence, we find a representation for nuclear TMCs that is approximately independent of the nuclear target. We go on to construct a single-parameter fit for all nuclear targets that is in good numerical agreement with full computations of TMCs. We discuss in detail qualitative and quantitative differences between nuclear TMCs built in the OPE and the parton model formalisms, as well as give numerical predictions for current and future facilities.
Comments:
journal version: 96 pages (including two appendices and references), many plots and figures, extended/improved discussions
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2301.07715 [pdf]
PPNP(2024)·33 citations
09
[Submitted on 18 Jan 2023] (cross-list from hep-ph)
Nucleon Resonance Electroexcitation Amplitudes and Emergent Hadron Mass
Daniel S. Carman🇺🇸 · Ralf W. Gothe🇺🇸 · Victor I. Mokeev🇺🇸 · Craig D. Roberts🇨🇳
Understanding the strong interaction dynamics that govern the emergence of hadron mass (EHM) represents a challenging open problem in the Standard Model. In this paper we describe new opportunities for gaining insight into EHM from results on nucleon resonance ( $N^{*}$ ) electroexcitation amplitudes (i.e. $γ_{v} p N^{*}$ electrocouplings) in the mass range up to 1.8\,GeV for virtual photon four-momentum squared (i.e. photon virtualities $Q^{2}$ ) up to 7.5\,GeV $^{2}$ available from exclusive meson electroproduction data acquired during the 6-GeV era of experiments at Jefferson Laboratory (JLab). These results, combined with achievements in the use of continuum Schwinger function methods (CSMs), offer new opportunities for charting the momentum dependence of the dressed quark mass from results on the $Q^{2}$ -evolution of the $γ_{v} p N^{*}$ electrocouplings. A successful description of the $Δ (1232) 3/ 2^{+}$ and $N (1440) 1/ 2^{+}$ electrocouplings has been achieved using CSMs with, in both cases, common momentum-dependent mass functions for the dressed quarks, for the gluons, and the same momentum-dependent strong coupling. Parameter-free CSM predictions for the electrocouplings of the $Δ (1600) 3/ 2^{+}$ became available in 2019. The experimental results obtained in the first half of 2022 have confirmed the CSM predictions. We also discuss prospects for these studies during the 12-GeV era at JLab using the CLAS12 detector, with experiments that are currently in progress, and canvass the physics motivation for continued studies in this area with a possible increase of the JLab electron beam energy up to 22\,GeV.
Comments:
23 pages, 11 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2301.07777 [pdf]
Particles(2023)·46 citations
10
[Submitted on 19 Jan 2023] (cross-list from hep-lat)
Nucleon form factors and the pion-nucleon sigma term
Rajan Gupta🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Vincenzo Cirigliano🇺🇸 · Martin Hoferichter🇨🇭 · Yong-Chull Jang🇺🇸 · Balint Joo🇺🇸 · Emanuele Mereghetti🇺🇸 · Santanu Mondal🇺🇸 · Sungwoo Park🇺🇸 · Frank Winter🇺🇸 · Boram Yoon🇺🇸
This talk summarizes the progress made since Lattice 2021 in understanding and controlling the contributions of towers of multihadron excited states with mass gaps starting lower than of radial excitations, and in increasing our confidence in the extraction of ground state nucleon matrix elements. The most clear evidence for multihadron excited state contributions (ESC) is in axial/pseudoscalar form factors that are required to satisfy the PCAC relation between them. The talk examines the broader question--which and how many of the theoretically allowed positive parity states $N (p) π (- p)$ , $N (0) π (0) π (0)$ , $N (p) π (0)$ , $N (0) π (p), \dots$ make significant contributions to a given nucleon matrix element? New data for the axial, electric and magnetic form factors are presented. They continue to show trends observed in Ref[1]. The N $^{2}$ LO $χ$ PT analysis of the ESC to the pion-nucleon sigma term, $σ_{π N}$ , has been extended to include the $Δ$ as an explicit degree of freedom [2]. The conclusion reached in Ref [3] that $N π$ and $N π π$ states each contribute about 10 MeV to $σ_{π N}$ , and the consistency between the lattice result with $N π$ state included and the phenomenological estimate is not changed by this improvement.
Comments:
10 pages, 5 figures. Talk presented at the 39th International Symposium on Lattice Field Theory (LATTICE2022) 8-3 August, 2022 Bonn, Germany. arXiv admin note: text overlap with arXiv:2203.05647
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.07885 [pdf]
PoS(2023)·5 citations
11
[Submitted on 19 Jan 2023] (cross-list from hep-ph)
Three-dimensional QCD phase diagram in the pNJL model
Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳
Based on the three-flavor Polyakov-looped Nambu $-$ Jona-Lasinio (pNJL) model, we have studied the structure of the three-dimensional QCD phase diagram with respect to the temperature, the baryon chemical potential, and the isospin chemical potential, by investigating the interplay among the chiral quark condensate, the pion condensate, and the Polyakov loop. While the pNJL model leads to qualitatively similar structure of the normal quark phase, the pion superfluid phase, and the Sarma phase as well as their phase boundaries, when compared to the NJL model, the inclusion of the Polyakov loop enlarges considerably the areas of the pion superfluid phase and the Sarma phase, and leads to critical end points at higher temperatures. With the contribution of the gluon dynamics effectively included, the present study is expected to give a more reliable prediction of the three-dimensional QCD phase diagram compared to that in the NJL model.
Comments:
8 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.07900 [pdf]
Nucl.Phys.Rev.(2023)·7 citations
12
[Submitted on 19 Jan 2023] (cross-list from hep-ph)
Relations for low-energy constants in baryon chiral perturbation theory with explicit $Δ (1232)$ derived from the chiral quark model
Jun Jiang🇨🇳 · Shao-Zhou Jiang🇨🇳 · Shi-Yuan Li🇨🇳 · Yan-Rui Liu🇨🇳 · Zong-Guo Si🇨🇳 · Hong-Qian Wang🇨🇳
We study the relations between low-energy constants (LECs) in the chiral Lagrangians with $Δ (1232)$ and those in the quark-level description model up to the third chiral order. Ten structure correspondences are involved in getting the relations. This situation is more complicated than the spin-1/2 baryon case. The obtained results may help to further investigations involving the $Δ (1232)$ baryons.
Comments:
Version accepted by Eur. Phys. J. C. 10 pages, 2 figures, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2301.08059 [pdf]
EPJC(2023)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE