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
09
[Submitted on 29 Jan 2021] (cross-list from hep-ph)
The mass radius of the proton
Dmitri E. Kharzeev🇺🇸
The mass radius is a fundamental property of the proton that so far has not been determined from experiment. Here we show that the mass radius of the proton can be rigorously defined through the formfactor of the trace of the energy-momentum tensor (EMT) of QCD in the weak gravitational field approximation, as appropriate for this problem. We then demonstrate that the scale anomaly of QCD enables the extraction of the formfactor of the trace of the EMT from the data on threshold photoproduction of $J / ψ$ and $Υ$ quarkonia, and use the recent GlueX Collaboration data to extract the r.m.s. mass radius of the proton $R_{m} = 0.55 \pm 0.03 fm$ . The extracted mass radius is significantly smaller than the charge radius of the proton $R_{C} = 0.8409 \pm 0.0004 fm$ . We attribute this difference to the interplay of asymptotic freedom and spontaneous breaking of chiral symmetry in QCD, and outline future measurements needed to determine the mass radius more precisely.
Comments:
20 pages, 3 figures; 2 typos fixed
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2102.00110 [pdf]
PRD(2021)·143 citations
10
[Submitted on 30 Jan 2021] (cross-list from hep-lat)
Dibaryon with highest charm number near unitarity from lattice QCD
Yan Lyu🇨🇳 · Hui Tong🇨🇳 · Takuya Sugiura🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Jie Meng🇨🇳 · Takaya Miyamoto🇯🇵
A pair of triply charmed baryons, $Ω_{ccc} Ω_{ccc}$ , is studied as an ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical light-quark masses and the relativistic heavy quark action with the physical charm quark mass. The spatial baryon-baryon correlation is related to their scattering parameters on the basis of the HAL QCD method. The $Ω_{ccc} Ω_{ccc}$ in the $^{1} S_{0}$ channel taking into account the Coulomb repulsion with the charge form factor of $Ω_{ccc}$ leads to the scattering length $a_{0}^{C} ≃ - 19 fm$ and the effective range $r_{eff}^{C} ≃ 0.45 fm$ . The ratio $r_{eff}^{C} / a_{0}^{C} ≃ - 0.024$ , whose magnitude is considerably smaller than that of the dineutron ( $- 0.149$ ), indicates that $Ω_{ccc} Ω_{ccc}$ is located in the unitary regime.
Comments:
6 pages, 4 figures; Supplemental Material(1 page, 1 figure); Accepted for publication in Physical Review Letters
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2102.00181 [pdf]
PRL(2021)·94 citations
11
[Submitted on 31 Jan 2021] (cross-list from physics.atom-ph)
Nuclear polarization effects in atoms and ions
V.V. Flambaum🇦🇺 · I.B. Samsonov🇦🇺 · H.B. Tran Tan🇦🇺 · A.V. Viatkina🇩🇪
In heavy atoms and ions, nuclear structure effects are significantly enhanced due to the overlap of the electron wave functions with the nucleus. This overlap rapidly increases with the nuclear charge $Z$ . We study the energy level shifts induced by the electric dipole and electric quadrupole nuclear polarization effects in atoms and ions with $Z \geq 20$ . The electric dipole polarization effect is enhanced by the nuclear giant dipole resonance. The electric quadrupole polarization effect is enhanced because the electrons in a heavy atom or ion move faster than the rotation of the deformed nucleus, thus experiencing significant corrections to the conventional approximation in which they `see' an averaged nuclear charge density. The electric nuclear polarization effects are computed numerically for $1 s$ , $2 s$ , $2 p_{1/2}$ and high $n s$ electrons. The results are fitted with elementary functions of nuclear parameters (nuclear charge, mass number, nuclear radius and deformation). We construct an effective potential which models the energy level shifts due to nuclear polarization. This effective potential, when added to the nuclear Coulomb interaction, may be used to find energy level shifts in multi-electron ions, atoms and molecules. The fitting functions and effective potentials of the nuclear polarization effects are important for the studies of isotope shifts and nonlinearity in the King plot which are now used to search for new interactions and particles.
Comments:
17 pages, 3 figures, 10 tables
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
arXiv:
2102.00355 [pdf]
PRA(2021)·15 citations
12
[Submitted on 1 Feb 2021] (cross-list from hep-ph)
Neutrino-nucleon DIS from Holographic QCD: PDFs of sea and valence quarks, form factors, and structure functions of the proton
Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸
We discuss unpolarized neutrino- and anti-neutrino-nucleon deep inelastic scattering (DIS) using a chiral doublet of baryonic sources with explicit symmetry breaking, in a slice of AdS $_{5}$ with both a hard and soft wall. We explicitly derive the direct and transition form factors for the vector and axial-vector currents for the holographic dual of a proton and neutron. We use them to derive the s-channel structure functions for neutrino and anti-neutrino scattering on a proton and neutron in bulk. The t-channel contributions stemming from the Pomeron and Reggeon exchanges are also evaluated explicitly. The pertinent even and odd structure functions in the limit of large and small parton momentum fraction $x$ are given. The results allow for the extraction of the nonperterbative parton distribution functions carried by the sea and valence quarks both at large-x and small-x regimes. Our holographic PDF sets compare well with LHAPDF and CTEQ PDF sets in the large-x and small-x regimes in the intermediate range of $Q^{2} < 10 Ge V^{2}$ .
Comments:
54 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2102.00608 [pdf]
PRD(2021)·8 citations
13
[Submitted on 1 Feb 2021] (cross-list from hep-ph)
The $Λ (1405)$ in resummed chiral effective field theory
X.-L. Ren🇩🇪 · E. Epelbaum🇩🇪 · J. Gegelia🇩🇪 · Ulf-G. Meißner🇩🇪
We study the unitarized meson-baryon scattering amplitude at leading order in the strangeness $S = - 1$ sector using time-ordered perturbation theory for a manifestly Lorentz-invariant formulation of chiral effective field theory. By solving the coupled-channel integral equations with the full off-shell dependence of the effective potential and applying subtractive renormalization, we analyze the renormalized scattering amplitudes and obtain the two-pole structure of the $Λ (1405)$ resonance. We also point out the necessity of including higher-order terms.
Comments:
16 pages, 3 figures, 5 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.00914 [pdf]
EPJC(2021)·11 citations
14
[Submitted on 1 Feb 2021] (cross-list from astro-ph.HE)
Maximum mass of compact stars from gravitational wave events with finite-temperature equations of state
Sanika Khadkikar🇮🇳 · Adriana R. Raduta🇷🇴 · Micaela Oertel🇫🇷 · Armen Sedrakian🇩🇪
We conjecture and verify a set of universal relations between global parameters of hot and fast-rotating compact stars, including a relation connecting the masses of the mass-shedding (Kepler) and static configurations. We apply these relations to the GW170817 event by adopting the scenario in which a hypermassive compact star remnant formed in a merger evolves into a supramassive compact star that collapses into a black hole once the stability line for such stars is crossed. We deduce an upper limit on the maximum mass of static, cold neutron stars $2.1 5_{- 0.07}^{+ 0.10} \leq M_{TOV}^{⋆} \leq 2.2 4_{- 0.10}^{+ 0.12}$ for the typical range of entropy per baryon $2 \leq S / A \leq 3$ and electron fraction $Y_{e} = 0.1$ characterizing the hot hypermassive star. Our result implies that accounting for the finite temperature of the merger remnant relaxes previously derived constraints on the value of the maximum mass of a cold, static compact star.
Comments:
17 pages, 11 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2102.00988 [pdf]
PRC(2021)·65 citations

Affiliations

first authorsco-authorsvia INSPIRE