Nuclear Theory·nucl-th

Wednesday·June 3, 2020

12 papers—5 primary·7 cross-listed

01
[Submitted on 1 Jun 2020]
Effects of the QCD phase transition on hadronic observables in relativistic hydrodynamic simulations of heavy-ion reactions in the FAIR/NICA energy regime
Christian Spieles🇩🇪 · Marcus Bleicher🇩🇪
We investigate hadronic particle spectra and flow characteristics of heavy-ion reactions in the FAIR/NICA energy range of $1 A GeV \leq E_{lab} \leq 10 A GeV$ within a relativistic ideal hydrodynamic one-fluid approach. The particlization is realized by sampling the Cooper-Frye distribution for a grand canonical hadron gas on a hypersurface of constant energy density. Results of the hydrodynamic calculations for different underlying equations of state are presented and compared with experimental data and microscopic transport simulations. The sensitivity of the approach to physical model inputs concerning the initial state and the particlization is studied.
Comments:
Submitted to EPJ ST
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.01220 [pdf]
Eur.Phys.J.ST(2020)·16 citations
02
[Submitted on 2 Jun 2020]
Quantum Simulation of Nuclear Inelastic Scattering
Weijie Du🇨🇳 · James P. Vary🇺🇸 · Xingbo Zhao🇨🇳 · Wei Zuo🇨🇳
We present a time-dependent quantum algorithm for nuclear inelastic scattering in the time-dependent basis function on qubits approach. This algorithm aims to quantum simulate a subset of the nuclear inelastic scattering problems that are of physical interest, in which the internal degrees of freedom of the reaction system are excited by time-dependent external interactions. We expect that our algorithm will enable an exponential speedup in simulating the dynamics of the subset of the inelastic scattering problems, which would also be advantageous for the applications to more complicated scattering problems. For a demonstration problem, we solve for the Coulomb excitation of the deuteron, where the quantum simulations are performed with IBM Qiskit.
Comments:
4 figures, 1 table, 25 pages. Accepted by Phys. Rev. A. Comments are welcome!
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2006.01369 [pdf]
PRA(2021)·47 citations
03
[Submitted on 2 Jun 2020]
Symmetry energy properties of neutron-rich nuclei from the coherent density fluctuation model applied to nuclear matter calculations with Bonn potentials
I. C. Danchev · A. N. Antonov · D. N. Kadrev · M. K. Gaidarov · P. Sarriguren · E. Moya de Guerra
We derive the values of nuclear symmetry energy, its components, as well as pressure in finite nuclei at saturation density from their corresponding values in nuclear matter obtained in non-relativistic Brueckner-Hartree-Fock calculations with the realistic Bonn B and Bonn CD potentials using the coherent density fluctuation model in the framework of a self-consistent Skyrme-Hartree-Fock plus BCS method. We focus on three isotopic chains of spherical nuclei (Ni, Sn, and Pb) and compare our results with those obtained with an effective Brueckner density-dependent potential. The role of the three-body forces on the considered quantities is also studied and discussed.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.01471 [pdf]
PRC(2020)·11 citations
04
[Submitted on 2 Jun 2020]
Low-energy 11Li + p and 11Li + d scattering in a multicluster model
Pierre Descouvemont
The 11Li + p and 11Li + d reactions are investigated in the Continuum Discretized Coupled Channel (CDCC) method with a three-body description (9Li + n + n) of 11Li. I first discuss the properties of 11Li, and focus on E1 transition probabilities to the continuum. The existence of a 1- resonance at low excitation energies is confirmed, but the associated E1 transition from the ground state does not have an isoscalar character, as suggested in a recent experiment. In a second step, I study the 11Li + p elastic cross section at Elab = 66 MeV in the CDCC framework. I obtain a fair agreement with experiment, and show that breakup effects are maximal at large angles. The breakup cross section is shown to be dominated by the 1- dipole state in 11Li, but the role of this resonance is minor in elastic scattering. From CDCC equivalent 11Li + p and 11Li + n potentials, I explore the 11Li + d cross section within a standard three-body 11Li +(p + n) model. At small angles, the experimental cross section is close to the Rutherford scattering cross section, which is not supported by the CDCC. A five-body (9Li+n+n)+(p+n) is then performed. Including breakup states in 11Li and in the deuteron represents a numerical challenge for theory, owing to the large number of channels. Although a full convergence could not be reached, the CDCC model tends to overestimate the data at small angles. I suggest that measurements of the 9Li + p elastic scattering would be helpful to determine more accurate optical potentials. The current disagreement between experiment and theory on 11Li + d scattering also deserves new experiments at other energies.
Comments:
12 pages, 10 figures, accepted at Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2006.01548 [pdf]
PRC(2020)·15 citations
05
[Submitted on 31 May 2020]
Minimal Theory of Isomerism -Q.Q and Other Interactions
Praveen Srivastava · Larry Zamick
We perform shell model calculations using a quadrupole-quadrupole interaction (Q.Q) in single a j shell space. We show that this one-parameter interaction is a good predictor of where nuclear isomerism occurs and where it does not occur. The limitations of this interaction are also discussed. We then include other interactions e.g. in the f_{7/2} shell those obtained from the (local) spectrum of a 2 particle system and then from a 2 hole system. In the g_{9/2}where there is insufficient empirical data from the 2 hole system and so various empirical interactions are used.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2006.01637 [pdf]
Phys.Scripta(2021)·5 citations
06
[Submitted on 1 Jun 2020] (cross-list from hep-ph)
Unified weak/strong coupling framework for nuclear matter and neutron stars
Niko Jokela🇫🇮 · Matti Jarvinen🇮🇱 · Govert Nijs🇳🇱 · Jere Remes🇫🇮
Ab initio methods using weakly interacting nucleons give a good description of condensed nuclear matter up to densities comparable to the nuclear saturation density. At higher densities palpable strong interactions between overlapping nucleons become important; we propose that the interactions will continuously switch over to follow a holographic model in this region. In order to implement this, we construct hybrid equations of state (EoSs) where various models are used for low density nuclear matter, and the holographic V-QCD model is used for non-perturbative high density nuclear matter as well as for quark matter. We carefully examine all existing constraints from astrophysics of compact stars and discuss their implications for the hybrid EoSs. Thanks to the stiffness of the V-QCD EoS for nuclear matter, we obtain a large family of viable hybrid EoSs passing the constraints. We find that quark matter cores in neutron stars are unstable due to the strongly first order deconfinement transition, and predict bounds on the tidal deformability as well as on the radius of neutron stars. By relying on universal relations, we also constrain characteristic peak frequencies of gravitational waves produced in neutron star mergers.
Comments:
40 pages, 19 figures; v2: analysis of I-Love-Q relations added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2006.01141 [pdf]
PRD(2021)·78 citations
07
[Submitted on 1 Jun 2020] (cross-list from cond-mat.quant-gas)
The phase diagram of ultra quantum liquids
Dam Thanh Son · Mikhail Stephanov · Ho-Ung Yee
We discuss the dependence of the phase diagram of a hypothetical isotope of helium with nuclear mass less than 4 atomic mass units. We argue that with decreasing nucleus mass, the temperature of the superfluid phase transition (about 2.2 K in real He-4) increases, while that of the liquid-gas critical point (about 5.2 K in real He-4) decreases. We discuss various scenarios that may occur when the two temperatures approach each other and the order parameters of the superfluid and the liquid-gas phase transitions interact with each other. The simplest scenario, in which both order parameters become critical at particular values of the nuclear mass, temperature, and pressure, can be ruled out through on an analysis of the Landau theory. We argue that in the most likely scenario, as the nuclear mass decreases, first, a tricritical point appears on the line separating the superfluid and the normal fluid phase, then the critical point disappears under the first-order part of superfluid phase transition line, and in the end the tricritical point disappears. The last change in the phase diagram occurs when the two-body scattering length crosses zero, which corresponds to the nuclear mass of about 1.55 u. We develop a quantitative theory that allows one to determine the phase diagram in the vicinity of this point. Finally, we discuss several ways to physically realize such liquids.
Comments:
24 pages, 6 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
arXiv:
2006.01156 [pdf]
J.Stat.Mech.(2021)·4 citations
08
[Submitted on 2 Jun 2020] (cross-list from hep-ph)
Bound-free pair production in relativistic nuclear collisions from the NICA to the HE LHC colliders
D.A. Bauer🇷🇺 · D.V. Karlovets🇷🇺 · V.G. Serbo🇷🇺
We consider the electron-positron pair production in relativistic heavy ion collisions, in which the produced electron is captured by one of the nuclei resulting, thus, in the formation of a hydrogen--like ion. These ions emerge from the collision point and hit the vacuum chamber wall inside superconducting magnets. Therefore, this process may be important for the problems of beam life time and for the quenching the irradiated magnet. A theoretical investigation for such a bound-free pair production (BFPP) at the colliders from NICA to HE LHC is presented. We obtain an approximate universal formula for the total cross section of the process. We compare it with the results of available numerical calculations and estimate that an accuracy of our calculations is better than $30$ % at the energies of the NICA collider and becomes of the order of a few percent for the RHIC and HE LHC colliders. Based on the obtained results, the detailed calculations are performed for future experiments at the NICA collider. We find that the expected BFPP cross sections for the Au $^{79 +}$ -Au $^{79 +}$ and Bi $^{83 +}$ -Bi $^{83 +}$ collisions are in the range from $10$ to $70$ barn, while for the p-Au $^{79 +}$ and p-Bi $^{83 +}$ collisions they are in the range of a few mbarn.
Comments:
10 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2006.01377 [pdf]
EPJA(2020)·9 citations
09
[Submitted on 2 Jun 2020] (cross-list from hep-lat)
S-wave kaon-nucleon potentials with all-to-all propagators in the HAL QCD method
Kotaro Murakami🇯🇵 · Yutaro Akahoshi🇯🇵 · Sinya Aoki🇯🇵
In this paper, employing an all-to-all quark propagator technique, we investigate the kaon-nucleon interactions in lattice QCD. We calculate the S-wave kaon-nucleon potentials at the leading order in the derivative expansion in the time-dependent HAL QCD method, using (2+1)-flavor gauge configurations at the lattice spacing $a \approx 0.09$ fm on $3 2^{3} \times 64$ lattices and the pion mass $m_{π} \approx 570$ MeV. We take the one-end trick for all-to-all propagators, which allows us to put the zero momentum hadron operators at both source and sink and to smear quark operators at the source. We find the stronger repulsive interaction in the $I = 1$ channel than in the $I = 0$ . The phase shifts obtained by solving the Schrödinger equations with the potentials qualitatively reproduce the energy dependence of the experimental phase shifts, and have the similar behavior to the previous results from lattice QCD without all-to-all propagators. Our study demonstrates that the all-to-all quark propagator technique with the one-end trick is useful to study interactions for meson-baryon systems in the HAL QCD method, so that we will apply it to meson-baryon systems which contain quark-antiquark creation/annihilation processes in our future studies.
Comments:
18 pages, 7 figures, 1 table
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2006.01383 [pdf]
PTEP(2020)·7 citations
10
[Submitted on 2 Jun 2020] (cross-list from cond-mat.quant-gas)
From weak to strong: constrained extrapolation of perturbation series with applications to dilute Fermi systems
C. Wellenhofer🇩🇪 · D. R. Phillips🇩🇪 · A. Schwenk🇩🇪
We develop a method that uses truncation-order-dependent re-expansions constrained by generic strong-coupling information to extrapolate perturbation series to the nonperturbative regime. The method is first benchmarked against a zero-dimensional model field theory and then applied to the dilute Fermi gas in one and three dimensions. Overall, our method significantly outperforms Padé and Borel extrapolations in these examples. The results for the ground-state energy of the three-dimensional Fermi gas are robust with respect to changes of the form of the re-expansion and compare well with quantum Monte Carlo simulations throughout the BCS regime and beyond.
Comments:
minor improvements, matches published version; 11 pages, 8 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2006.01429 [pdf]
PRResearch(2020)·8 citations
11
[Submitted on 2 Jun 2020] (cross-list from hep-ph)
Charged charm stars
V. P. Goncalves🇧🇷 · L. Lazzari🇧🇷
The study of the general properties and stability of charm stars with a net electric charge is performed within the MIT bag model framework. We consider two different models for the electric charge distribution and demostrate that both imply stellar configurations with larger masses and that satisfy the equilibrium condition. The dynamical stability against radial oscillations is investigated. Our results demonstrate that the eigenfrequencies are modified by the presence of a net electric charge, but the instability, previously demonstrated for the electrically neutral case, is also present in charged charm stars.
Comments:
5 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2006.01624 [pdf]
NPA(2020)·1 citation
12
[Submitted on 2 Jun 2020] (cross-list from hep-ph)
Mapping reactor neutrino spectra from TAO to JUNO
Francesco Capozzi🇩🇪 · Eligio Lisi🇮🇹 · Antonio Marrone🇮🇹
The Jiangmen Underground Neutrino Observatory (JUNO) project aims at probing, at the same time, the two main frequencies of three-flavor neutrino oscillations, as well as their interference related to the mass ordering (normal or inverted), at a distance of ~53 km from two powerful reactor complexes in China, at Yangjiang and Taishan. In the latter complex, the unoscillated spectrum from one reactor core is planned to be closely monitored by the Taishan Antineutrino Observatory (TAO), expected to have better resolution (x 1/2) and higher statistics (x 30) than JUNO. In the context of neutrino energy spectra endowed with fine-structure features from summation calculations, we analyze in detail the effects of energy resolution and nucleon recoil on observable event spectra. We show that a model spectrum in TAO can be mapped into a corresponding spectrum in JUNO through appropriate convolutions. The mapping is exact in the hypothetical case without oscillations, and holds to a very good accuracy in the real case with oscillations. We then analyze the sensitivity to mass ordering of JUNO (and its precision oscillometry capabilities) assuming a single reference spectrum, as well as bundles of variant spectra, as obtained by changing nuclear input uncertainties in summation calculations from a publicly available toolkit. We show through a chi-squared analysis that variant spectra induce little reduction of the sensitivity in JUNO, especially when TAO constraints are included. Subtle aspects of the statistical analysis of variant spectra are also discussed.
Comments:
23 pages, including 15 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2006.01648 [pdf]
PRD(2020)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE