Nuclear Theory·nucl-th

Tuesday·June 8, 2021

8 papers—5 primary·3 cross-listed

01
[Submitted on 4 Jun 2021]
Ladder resummation of spin 1/2 fermion many-body systems with arbitrary partial-wave content
J. M. Alarcón🇪🇸 · J. A. Oller🇪🇸
We resum the ladder diagrams for the calculation of the energy density $E$ of a spin 1/2 fermion many-body system in terms of arbitrary vacuum two-body scattering amplitudes. The partial-wave decomposition of the in-medium two-body scattering amplitudes is developed, and the expression for calculating $E$ in a partial-wave amplitude expansion is also given. The case of contact interactions is completely solved and is shown to provide renormalized results, expressed directly in terms of scattering data parameters, within cutoff regularization in a wide class of schemes. $S$ - and $P$ -wave interactions are considered up to including the first three-terms in the effective-range expansion, paying special attention to the parametric region around the unitary limit.
Comments:
58 pages, 16 figures, 2 table. New version to match the accepted manuscript in Annals of Physics. Pole content and pairing is further discussed
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2106.02652 [pdf]
Annals Phys.(2022)·10 citations
02
[Submitted on 6 Jun 2021]
Systematic study of surface properties for Ne, Na, Mg, Al and Si isotopes in a coherent density fluctuation model using the relativistic mean field formalism
Jeet Amrit Pattnaik · R. N. Panda · M. Bhuyan · S. K. Patra
We have systematically studied the surface properties, such as symmetric energy, neutron pressure, and symmetry energy curvature coefficient for Ne, Na, Mg, Al, and Si nuclei from the proton to neutron drip-lines. The Coherent Density Fluctuation Model (CDFM) is used to estimate these quantities taking the relativistic mean-field densities as inputs. The Brückner energy density functional is taken for the nuclear matter binding energy and local density approximation is applied for its conversion to coordinate space. The symmetry energy again decomposed to the volume and surface components within the liquid drop model formalism to the volume and surface parts separately. Before calculating the surface properties of finite nuclei, the calculated bulk properties are compared with the experimental data, whenever available. The NL3* parameter set with the BCS pairing approach in an axially deformed frame-work is used to take care of the pairing correlation when needed. The deformed density is converted to its spherical equivalent with a two Gaussian fitting, which is used as an input for the calculation of weight function in the CDFM approximation. With the help of the symmetric energy for the recently isotopes $^{29}$ F, $^{28}$ Ne, $^{29, 30}$ Na and $^{31, 35, 36}$ Mg are considered to be within the {\it island of inversion} emphasized {\bf [Phys. Lett. B 772, 529 (2017)]}. Although we get large symmetric energies corresponding to a few neutron numbers for this isotopic chain as expected, an irregular trend appears for all these considered nuclei. The possible reason behind this abnormal behavior of symmetry energy for these lighter mass nuclei is also included in the discussion, which gives a direction for future analysis.
Comments:
11 pages, 8 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2106.03038 [pdf]
Can.J.Phys.(2022)·9 citations
03
[Submitted on 7 Jun 2021]
Effects of three-baryon forces on kaon condensation in hyperon-mixed matter
Takumi Muto🇯🇵 · Toshiki Maruyama🇯🇵 · Toshitaka Tatsumi🇯🇵
Possibility of kaon-condensed phase in hyperon-mixed matter is considered on the basis of chiral symmetry for kaon-baryon and kaon-kaon interactions, being combined with the relativistic mean-field theory for two-body baryon interaction. In addition, universal three-baryon repulsive force in the string-junction model and phenomenological three-nucleon attractive force are introduced. It is shown that softening of the equation of state stemming from both kaon condensation and mixing of hyperons is compensated with the repulsive effect of the three-baryon force and the relativistic effect for two-body baryon-baryon interaction. The latter effect reflects the density-dependence of scalar and vector meson mean-fields, which is constrained by the contribution of the attractive three-nucleon force to the binding energy at saturation density. The kaon-condensed phase in hyperon-mixed matter becomes stiff enough to be consistent with recent observations of massive neutron stars.
Comments:
6 pages, 3 figures Some sentences and related references are added
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2106.03449 [pdf]
PLB(2021)·24 citations
04
[Submitted on 7 Jun 2021]
Systematic study of the Chiral Magnetic Effect with the AVFD model at LHC energies
Panos Christakoglou🇳🇱 · Shi Qiu🇳🇱 · Joey Staa🇳🇱
We present a systematic study of the correlators used experimentally to probe the Chiral Magnetic Effect (CME) using the Anomalous Viscous Fluid Dynamics (AVFD) model in Pb--Pb and Xe--Xe collisions at LHC energies. We find a parametrization that describes the dependence of these correlators on the value of the axial current density ( $n_{5} / s$ ), which dictates the CME signal, and on the parameter that governs the background in these measurements i.e., the percentage of local charge conservation (LCC) within an event. This allows to deduce the values of $n_{5} / s$ and the LCC percentage that provide a quantitative description of the centrality dependence of the experimental measurements. We find that the results in Xe--Xe collisions at $s_{NN} = 5.44$ ~TeV are consistent with a background only scenario. On the other hand, the model needs a significant non-zero value of $n_{5} / s$ to match the measurements in Pb--Pb collisions at $s_{NN} = 5.02$ ~TeV.
Comments:
10 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2106.03537 [pdf]
EPJC(2021)·17 citations
05
[Submitted on 7 Jun 2021]
Crust-core transition of a neutron star: effect of the temperature under strong magnetic fields
Márcio Ferreira🇵🇹 · Aziz Rabhi🇵🇹 · Constança Providência🇵🇹
The effect of temperature on the crust-core transition of a magnetar is studied. The thermodynamical spinodals are used to calculate the transition region within a relativistic mean-field approach for the equation of state. Magnetic fields with intensities $5 \times 1 0^{16}$ G and $5 \times 1 0^{17}$ G are considered. It is shown that the effect on the extension of the crust-core transition is washed away for temperatures above $1 0^{9}$ K for magnetic field intensities $≲ 5 \times 1 0^{16}$ G but may still persist if a magnetic field as high as $5 \times 1 0^{17}$ G is considered. For temperatures below that value, the effect of the magnetic field on crust-core transition is noticeable and grows as the temperature decreases and, in particular, it is interesting to identify the existence of disconnected non-homogeneous matter above the $B = 0$ crust core transition density. Models with different symmetry energy slopes at saturation show quite different behaviors. In particular, a model with a large slope, as suggested by the recent results of PREX-2, predicts the existence of up to four disconnected regions of non-homogeneous matter above the zero magnetic field crust-core transition density.
Comments:
9 pages, 5 figures, published version; Topical Issue "The QCD Phase Diagram in Strong Magnetic Fields"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2106.03590 [pdf]
EPJA(2021)·7 citations
06
[Submitted on 4 Jun 2021] (cross-list from astro-ph.HE)
Bayesian model-selection of neutron star equation of state using multi-messenger observations
Bhaskar Biswas🇮🇳
Measurement of macroscopic properties of neutron stars, whether in binary or in an isolated system, provides us a key opportunity to place a stringent constraint on its equation of state. In this paper, we perform Bayesian model-selection on a wide variety of neutron star equation of state using multi-messenger observations. In particular, (i) we use the mass and tidal deformability measurement from two binary neutron star merger event, GW170817 and GW190425; (ii) simultaneous mass-radius measurement of PSR J0030+0451 and PSR J0740+6620 by NICER collaboration, while the latter has been analyzed by joint NICER/radio/XMM-Newton collaboration. Among the 31 equations of state considered in this analysis, we are able to rule out different variants of MS1 family, SKI5, H4, and WFF1 EoSs decisively, which are either extremely stiff or soft equations of state. The most preferred equation of state model turns out to be AP3 (or MPA1), which predicts the radius and dimensionless tidal deformability of a $1.4 M_{⊙}$ neutron star to be 12.10 (12.50) km and 393 (513) respectively.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2106.02644 [pdf]
ApJ(2022)·66 citations
07
[Submitted on 5 Jun 2021] (cross-list from hep-ph)
Neutrino-Nucleus scattering in the SuSA model
J.E. Amaro🇪🇸 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · T.W. Donnelly🇺🇸 · R. Gonzalez-Jimenez🇪🇸 · G.D. Megias🇪🇸 · I. Ruiz Simo🇪🇸
The Super-Scaling Approach (SuSA) model, based on the analogies between electron and neutrino interactions with nuclei, is reviewed and its application to the description of neutrino-nucleus scattering is presented. The contribution of both one- and two-body relativistic currents is considered. A selection of results is presented where theoretical predictions are compared with cross section measurements from the main ongoing neutrino oscillation experiments.
Comments:
20 pages, 13 figures; submitted to EPJ-ST
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2106.02857 [pdf]
Eur.Phys.J.ST(2021)·29 citations
08
[Submitted on 7 Jun 2021] (cross-list from hep-ph)
Classifying near-threshold enhancement using deep neural network
Denny Lane B. Sombillo🇵🇭 · Yoichi Ikeda🇯🇵 · Toru Sato🇯🇵 · Atsushi Hosaka🇯🇵
One of the main issues in hadron spectroscopy is to identify the origin of threshold or near-threshold enhancement. Prior to our study, there is no straightforward way of distinguishing even the lowest channel threshold-enhancement of the nucleon-nucleon system using only the cross-sections. The difficulty lies in the proximity of either a bound or virtual state pole to the threshold which creates an almost identical structure in the scattering region. Identifying the nature of the pole causing the enhancement falls under the general classification problem and supervised machine learning using a feed-forward neural network is known to excel in this task. In this study, we discuss the basic idea behind deep neural network and how it can be used to identify the nature of the pole causing the enhancement. The applicability of the trained network can be explored by using an exact separable potential model to generate a validation dataset. We find that within some acceptable range of the cut-off parameter, the neural network gives high accuracy of inference. The result also reveals the important role played by the background singularities in the training dataset. Finally, we apply the method to nucleon-nucleon scattering data and show that the network was able to give the correct nature of pole, i.e. virtual pole for $^{1} S_{0}$ partial cross-section and bound state pole for $^{3} S_{0}$ .
Comments:
10 pages, 4 figures, Contribution to the Proceedings for 8th Asia-Pacific Conference on Few-Body Problems in Physics (APFB2020), March 1-5 2021, Kanazawa, Japan
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2106.03453 [pdf]
Few Body Syst.(2021)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE