Nuclear Theory·nucl-th

Tuesday·February 2, 2021

14 papers—8 primary·6 cross-listed

01
[Submitted on 30 Jan 2021]
$η$ mesons in hot magnetized nuclear matter
Rajesh Kumar🇮🇳 · Arvind Kumar🇮🇳
The $η N$ interactions are investigated in the hot magnetized asymmetric nuclear matter using chiral SU(3) model and chiral perturbation theory (ChPT). In the chiral model, the in-medium properties of $η$ -meson are calculated by the medium modified scalar densities under the influence of an external magnetic field. Further, in the combined approach of chiral model and ChPT, off-shell contributions of $η N$ interactions are evaluated from the ChPT effective $η N$ Lagrangian, and the in-medium effect of scalar densities are incorporated from the chiral SU(3) model. We observe a significant effect of magnetic field on the in-medium mass and optical potential of $η$ meson. We observe a deeper mass-shift in the combined approach of ChPT and chiral model compared to the effect of solo chiral SU(3) model. In both approaches, no additional mass-shift is observed due to the uncharged nature of $η$ mesons in the presence of magnetic field.
Comments:
34 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2102.00192 [pdf]
CPC(2022)·2 citations
02
[Submitted on 1 Feb 2021]
Successive variational approach with the tensor-optimized antisymmetrized molecular dynamics for the $^{5}$ He nucleus
Takayuki Myo🇯🇵 · Mengjiao Lyu🇨🇳 · Hiroshi Toki🇯🇵 · Hisashi Horiuchi🇯🇵
We study $^{5}$ He variationally as the first $p$ -shell nucleus in the tensor-optimized antisymmetrized molecular dynamics (TOAMD) using the bare nucleon--nucleon interaction without any renormalization. In TOAMD, the central and tensor correlation operators promote the AMD's Gaussian wave function to a sophisticated many-body state including the short-range and tensor correlations with high-momentum nucleon pairs. We develop a successive approach by applying these operators successively with up to double correlation operators to get converging results. We obtain satisfactory results for $^{5}$ He, not only for the ground state but also for the excited state, and discuss explicitly the correlated Hamiltonian components in each state. We also show the importance of the independent optimization of the correlation functions in the variation of the total energy beyond the condition assuming common correlation forms used in the Jastrow approach.
Comments:
14 pages, 6 figures, published in Progress of Theoretical and Experimental Physics
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.00638 [pdf]
PTEP(2021)·3 citations
03
[Submitted on 1 Feb 2021]
Antikaon-induced $K_{1} (1270)^{+}$ meson production on nuclei near threshold
E. Ya. Paryev🇷🇺
We study the inclusive strange axial-vector meson $K_{1} (1270)^{+}$ production in $K^{-} A$ reactions at near-threshold laboratory incident antikaon momenta within a nuclear spectral function approach, which describes incoherent direct $K_{1} (1270)^{+}$ meson production in $K^{-}$ meson--proton $K^{-} p \to K_{1} (1270)^{+} Ξ^{-}$ production processes and accounts for three different options for its in-medium mass shift (or for its effective scalar potential) at central density $ρ_{0}$ . We calculate the absolute differential and total cross sections for the production of $K_{1} (1270)^{+}$ mesons on $^{12}$ C and $^{184}$ W target nuclei at laboratory angles of 0 $^{\circ}$ --45 $^{\circ}$ by $K^{-}$ mesons with momenta of 2.5, 2.8 and 3.5 GeV/c, which are close to the threshold momentum ( $\approx$ 2.95 GeV/c) for $K_{1} (1270)^{+}$ meson production off the free target proton at rest. The intrinsic properties of carbon and tungsten target nuclei have been described in terms of their spectral functions, which take into account the momenta of target protons and the energies of their separation from the considered nuclei. We show that the differential and total (absolute and relative) $K_{1} (1270)^{+}$ antikaon-induced production cross sections at initial momenta not far from threshold -- at momenta $\sim$ 2.8--3.5 GeV/c, at which there is yet no strong drop in their strength, reveal a distinct sensitivity to changes in the in-medium shift of the $K_{1} (1270)^{+}$ mass, studied in the paper, both in the $K_{1} (1270)^{+}$ meson low-momentum (0.1--1.0 GeV/c) and in its full-momentum ranges. This would permit evaluating this shift. Experimental data necessary for this aim can be obtained in a dedicated experiment at the J-PARC Hadron Experimental Facility.
Comments:
20 pages. arXiv admin note: substantial text overlap with arXiv:2007.10192
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2102.00789 [pdf]
NPA(2021)·3 citations
04
[Submitted on 1 Feb 2021]
Uncertainty evaluation and correlation analysis of single-particle energies in phenomenological nuclear mean field: An investigation of propagating uncertainties for independent model parameters
Zhen-Zhen Zhang🇨🇳 · Hua-Lei Wang🇨🇳 · Hai-Yan Meng🇨🇳 · Min-Liang Liu🇨🇳
Based on Monte Carlo approach and conventional error analysis theory, taking the heaviest doubly magic nucleus $^{208}$ Pb as an example, we firstly evaluate the propagated uncertainties of universal potential parameters for three typical types of single-particle energies in the phenomenological Woods-Saxon mean field. Accepting the Woods-Saxon modeling with uncorrelated model parameters, we find that the standard deviations of single-particle energies obtained by the Monte Carlo simulation and the error propagation rules are in good agreement with each other. It seems that the energy uncertaintis of the single-particle levels regularly evoluate with some quantum numbers to a large extent for the given parameter uncertainties. Further, the correlation properties of the single-particle levels within the domain of input parameter uncertainties are analyzed using the method of statistical analysis, e.g., with the aid of Pearson correlation coefficients. It is found that the positive, negative or unrelated relationship may appear between two selected single-particle levels, which will be very helpful for evaluating the theoretical uncertainty related to the single-particle levels (e.g., $K$ isomer) in nuclear structural calculations.
Comments:
15 pages, 10 figures, accepted by Nuclear Science Techniques
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.00797 [pdf]
Nucl.Sci.Tech.(2021)·8 citations
05
[Submitted on 1 Feb 2021]
Strongly Interacting Matter Under Rotation: An Introduction
Francesco Becattini🇮🇹 · Jinfeng Liao🇺🇸 · Michael Lisa🇺🇸
Ultrarelativistic collisions between heavy nuclei briefly generate the quark-gluon plasma (QGP), a new state of matter characterized by deconfined partons last seen microseconds after the Big Bang. The properties of the QGP are of intense interest, and a large community has developed over several decades, to produce, measure and understand this primordial plasma. The plasma is now recognized to be a strongly-coupled fluid with remarkable properties, and hydrodynamics is commonly used to quantify and model the system. An important feature of any fluid is its vorticity, related to the local angular momentum density; however, this degree of freedom has received relatively little attention because no experimental signals of vorticity had been detected. Thanks to recent high-statistics datasets from experiments with precision tracking and complete kinemetic coverage at collider energies, hyperon spin polarization measurements have begun to uncover the vorticity of the QGP created at the Relativistic Heavy Ion Collider. The injection of this new degree of freedom into a relatively mature field of research represents an enormous opportunity to generate new insights into the physics of the QGP. The community has responded with enthusiasm, and this book (to be published as a volume of Lecture Notes in Physics series by Springer) represents some of the diverse lines of inquiry into aspects of strongly interacting matter under rotation.
Comments:
This is the introductory chapter of "Strongly Interacting Matter Under Rotation," a volume of Lecture Notes in Physics to be published by Springer and edited by Becattini, Liao, and Lisa. It briefly summarizes the topic and introduces the subsequent 11 chapters, written by experts from the community
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2102.00933 [pdf]
Lect.Notes Phys.(2021)·27 citations
06
[Submitted on 1 Feb 2021]
An $N / D$ study of the $S_{11}$ channel $π N$ scattering amplitude
Qu-Zhi Li🇨🇳 · Yao Ma🇨🇳 · Wen-Qi Niu🇨🇳 · Yu-Fei Wang🇩🇪 · Han-Qing Zheng🇨🇳
Extensive dynamical $N / D$ calculations are made in the study of $S_{11}$ channel low energy $π$ N scatterings, based on various phenomenological model inputs of left cuts at tree level. The subtleties of the singular behavior of the partial wave amplitude at the origin of the complex $s$ plane are carefully analysed. Furthermore, { it is found that the dispersion representation for the phase shift, $δ$ , has to be modified in the case of $π$ N scatterings. An additional contribution from the dispersion integral exists, which is, however, almost exactly cancelled the contribution from two virtual poles located near the end points of the segment cut induced by $u$ channel nucleon exchanges.} Relying very little on the details of the dynamical inputs, the subthreshold resonance $N^{*} (890)$ survives.
Comments:
Minor corrections, one reference added. Final version accepted for publication in Chinese Physics C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2102.00977 [pdf]
CPC(2022)·11 citations
07
[Submitted on 1 Feb 2021]
Energy Dependent Calculations of Fission Product, Prompt, and Delayed Neutron Yields for Neutron Induced Fission on $^{235}$ U, $^{238}$ U, and $^{239}$ Pu
S. Okumura · T. Kawano · A.E. Lovell · T. Yoshida
We perform energy dependent calculations of independent and cumulative fission product yields for $^{235}$ U, $^{238}$ U, and $^{239}$ Pu in the first chance fission region. Starting with the primary fission fragment distributions taken from available experimental data and analytical functions based on assumptions for the excitation energy and spin-parity distributions, the Hauser-Feshbach statistical decay treatment for fission fragment de-excitation is applied to more than 1,000 fission fragments for the incident neutron energies up to 5 MeV. The calculated independent fission product yields are then used as an input of $β$ -decay to produce the cumulative yield, and summation calculations are performed. Model parameters in these procedures are adjusted by applying the Bayesian technique at the thermal energy for $^{235}$ U and $^{239}$ Pu and in the fast energy range for $^{238}$ U. The calculated fission observable quantities, such as the energy-dependent fission yields, and prompt and delayed neutron yields, are compared with available experimental data. We also study a possible impact of the second chance fission opening on the energy dependence of the delayed neutron yield by extrapolating the calculation.
Subjects:
Nuclear Theory (nucl-th); physics.app-ph (physics.app-ph)
arXiv:
2102.01015 [pdf]
J.Nucl.Sci.Tech.(2021)·13 citations
08
[Submitted on 1 Feb 2021]
Nuclear spin features relevant to ab initio nucleon-nucleus elastic scattering
R. B. Baker · M. Burrows · Ch. Elster · K. D. Launey · P. Maris · G. Popa · S. P. Weppner
Background: Effective interactions for elastic nucleon-nucleus scattering from first principles require the use of the same nucleon-nucleon interaction in the structure and reaction calculations, as well as a consistent treatment of the relevant operators at each order. Purpose: Previous work using these interactions has shown good agreement with available data. Here, we study the physical relevance of one of these operators, which involves the spin of the struck nucleon, and examine the interpretation of this quantity in a nuclear structure context. Methods: Using the framework of the spectator expansion and the underlying framework of the no-core shell model, we calculate and examine spin-projected, one-body momentum distributions required for effective nucleon-nucleus interactions in $J = 0$ nuclear states. Results: The calculated spin-projected, one-body momentum distributions for $^{4}$ He, $^{6}$ He, and $^{8}$ He display characteristic behavior based on the occupation of protons and neutrons in single particle levels, with more nucleons of one type yielding momentum distributions with larger values. Additionally, we find this quantity is strongly correlated to the magnetic moment of the $2^{+}$ excited state in the ground state rotational band for each nucleus considered. Conclusions: We find that spin-projected, one-body momentum distributions can probe the spin content of a $J = 0$ wave function. This feature may allow future \textit{ab initio} nucleon-nucleus scattering studies to inform spin properties of the underlying nucleon-nucleon interactions. The observed correlation to the magnetic moment of excited states illustrates a previously unknown connection between reaction observables such as the analyzing power and structure observables like the magnetic moment.
Comments:
13 pages, 7 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.01025 [pdf]
PRC(2021)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE