Nuclear Theory·nucl-th

Tuesday·August 31, 2021

16 papers—9 primary·7 cross-listed

01
[Submitted on 27 Aug 2021]
Pions in Proton Structure and Everywhere Else
Mary Alberg (1,2)🇺🇸 · Lucas Ehinger (1)🇺🇸 · Gerald A. Miller (2) ((1) Seattle University, (2) University of Washington)🇺🇸
The pion cloud is important in nuclear physics and in a variety of low-energy hadronic phenomena. We argue that it is natural to expect it to also be important in lepton-proton deep inelastic scattering and Drell-Yan studies of proton structure. We compute the necessary consequences of the pion cloud in connection with the recent SeaQuest data. The effects are detailed by using the exact kinematics of the experiment. Good agreement with the measurements is obtained. Thus the universality of pionic effects is understood.
Comments:
8 pages, 5 figures. Expanded discussion, added references. This version accepted for publication. arXiv admin note: text overlap with arXiv:1712.05814
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2108.12439 [pdf]
PRD(2022)·12 citations
02
[Submitted on 27 Aug 2021]
Energy dependent ratios of level-density parameters in superheavy nuclei
A. Rahmatinejad · T. M. Shneidman · G. Adamian · N. V. Antonenko · P. Jachimowicz · M. Kowal
The nuclear level densities and level-density parameters in fissioning nuclei at their saddle points of fission barriers - $a_{f}$ , as well as those for neutron - $a_{n}$ , proton - $a_{p}$ , and $α$ -particle - $a_{α}$ emission residues at the ground states are calculated for isotopic chains of superheavy nuclei with $Z$ =112-120. The calculations are performed with the superfluid formalism using the single-particle energies obtained from the diagonalization of the deformed Woods-Saxon potential. Spectra were generated at global minima of the adiabatic potential energy surfaces, found by the multidimensional minimization method, and at the proper saddle points, found by the "immersion water flow" technique on multidimensional energy grids, with allowed the reflection and axial symmetry breaking. The influence of shell effects on the energy dependence of the ratios of level-density parameters corresponding to residues of the considered decay modes to those of neutron emission is studied. We have shown that, in contrast to the $a_{f} / a_{n}$ ratio, the $a_{p} / a_{n}$ and $a_{α} / a_{n}$ ratios do not show characteristic maxima depending on the excitation energy of the compound nucleus being formed. In the case of alpha decay, we identified the collective enhancement caused by cluster degrees of freedom to play quite an important role. The energetic course of the variability of the level density parameters before reaching the asymptotic value, not taken into account so far, will be of great importance for the estimation of the probabilities of de-excitation cascades via light particles emission in competition with splitting and thus for the determination of the survival probabilities and finally for the total production cross-sections of superheavy nuclei in channels with their (light particles) participation.
Comments:
submitted to PRC
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.12484 [pdf]
PRC(2022)·11 citations
03
[Submitted on 28 Aug 2021]
Quantal diffusion description of isotope production by multinucleon transfer mechanism in $^{48} Ca +^{238} U$ collisions
S. Ayik · M. Arik · E. C. Karanfil · O. Yilmaz · B. Yilmaz · A. S. Umar
As an extension of previous work, we calculate the production cross-section of heavy neutron-rich isotopes by employing the quantal diffusion description to $^{48} Ca +^{238} U$ collisions. The quantal diffusion is deduced from stochastic mean-field approach, and transport properties are determined in terms of time-dependent single-particle wave functions of the time-dependent Hartree-Fock (TDHF) theory. As a result, the approach allows for prediction of production cross-sections without any adjustable parameters. The secondary cross-sections by particle emission are calculated with the help of the statistical GEMINI++ code.
Comments:
9 pages, six figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.12694 [pdf]
PRC(2021)·19 citations
04
[Submitted on 29 Aug 2021]
Quark condensate and chiral symmetry restoration in neutron stars
Hao-Miao Jin🇨🇳 · Cheng-Jun Xia🇨🇳 · Ting-Ting Sun🇨🇳 · Guang-Xiong Peng🇨🇳
Based on an equivparticle model, we investigate the in-medium quark condensate in neutron stars. Carrying out a Taylor expansion of the nuclear binding energy to the order of $ρ^{3}$ , we obtain a series of EOSs for neutron star matter, which are confronted with the latest nuclear and astrophysical constraints. The in-medium quark condensate is then extracted from the constrained properties of neutron star matter, which decreases non-linearly with density. However, the chiral symmetry is only partially restored with non-vanishing quark condensates, which may vanish at a density that is out of reach for neutron stars.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2108.12736 [pdf]
PLB(2022)·11 citations
05
[Submitted on 29 Aug 2021]
Ambiguities from nuclear interactions in the $^{12}$ C( $p, 2 p$ ) $^{11}$ B reaction
Nguyen Tri Toan Phuc · Kazuyuki Ogata · Nguyen Hoang Phuc · Bui Duy Linh · Vo Hong Hai · Le Xuan Chung
We investigate the impact of ambiguities coming from the choice of optical potentials and nucleon-nucleon scattering cross sections on the spectroscopic factors extracted from the $^{12}$ C( $p, 2 p$ ) $^{11}$ B reaction. These ambiguities are evaluated by analyzing the cross sections of the $^{12}$ C( $p, 2 p$ ) $^{11}$ B reaction at 100 and 200 MeV within the framework of the distorted-wave impulse approximation with realistic choices of nuclear inputs. The results show that the studied ambiguities are considerably large in this energy region and careful choices of nuclear inputs used in the reaction calculations are required to extract reliable structure information.
Comments:
Accepted version by Communications in Physics. 16 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2108.12749 [pdf]
Commun.in Phys.(2022)·0 citations
06
[Submitted on 29 Aug 2021]
Sensitivity of quasi-free reactions on details of the bound-state overlap functions
C.A. Bertulani · A. Idini · C. Barbieri
It is often stated that heavy-ion nucleon knockout reactions are mostly sensitive to the tails of the bound-state wavefunctions. In contrast, (p,2p) and (p,pn) reactions are known to access information on the full overlap functions within the nucleus. We analyze the oxygen isotopic chain and explore the differences between single-particle wave functions generated with potential models, used in the experimental analysis of knockout reactions, and ab initio computations from self-consistent Green's function theory. Contrary to the common belief, we find that not only the tail of the overlap functions, but also their internal part are assessed in both reaction mechanisms, which are crucial to yield accurately determined spectroscopic information.
Comments:
6 pages, 6 figures, Physical Review C Letter, version accepted for publication
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2108.12932 [pdf]
PRC(2021)·13 citations
07
[Submitted on 30 Aug 2021]
Nuclear landscape in a mapped collective Hamiltonian from covariant density functional theory
Y. L. Yang · Y. K. Wang · P. W. Zhao · Z. P. Li
The nuclear landscape has been investigated within the triaxial relativistic Hartree-Bogoliubov theory with the PC-PK1 density functional, and the beyond-mean-field dynamical correlation energies are taken into account by a microscopically mapped five-dimensional collective Hamiltonian without additional free parameters. The effects of triaxial deformation and dynamical correlations on the nuclear landscape are analyzed. The present results provide the best description of the experimental binding energies, in particular for medium and heavy mass regions, in comparison with the results obtained previously with other state-of-the-art covariant density functionals. The inclusion of the dynamical correlation energies plays an important role in the PC-PK1 results. It is emphasized that the nuclear landscape is considerably extended by the PC-PK1 functional in comparison with the previous results with other density functionals, which may be due to the different isovector properties in the density functionals.
Comments:
10 pages, 3 figures. See http://nuclearmap.jcnp.org/index.html for the data of calculated ground-state properties and potential energy surfaces
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.13057 [pdf]
PRC(2021)·75 citations
08
[Submitted on 30 Aug 2021]
Hyperon dynamics and production of multi-strangeness hypernuclei in heavy-ion collisions at 3A GeV
Hui-Gan Cheng🇨🇳 · Zhao-Qing Feng🇨🇳
Within the microscopic transport, systematic investigation of the many facets of hyperons and hypernuclei up to strangeness $S = - 2$ are carried out for $^{197}$ Au + $^{197}$ Au and $^{40}$ Ca + $^{40}$ Ca at the incident energy of $3 A$ GeV. The spatial, temporal and density distributions of hyperon production, absorption and freeze-out are thoroughly investigated. The rapidity and kinetic energy spectra of $Ξ$ hyperons and double $Λ$ hypernuclei are analyzed. It is revealed that the chemical balance of hyperon production is established in baryon-baryon channels while the opposite is found in baryon-meson channels. It turns out that the rapidity spectra of $_{ΛΛ}^{4, 5}$ X are single-peak and more than two orders of magnitude lower than that of $_{Λ}^{3}$ H. Formation of double $Λ$ hypernuclei through $Ξ$ hypernuclei as intermediate states is also discussed in kinematics.
Comments:
10 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.13131 [pdf]
PLB(2022)·4 citations
09
[Submitted on 30 Aug 2021]
Fast & rigorous predictions for $A = 6$ nuclei with Bayesian posterior sampling
T. Djärv · A. Ekström · C. Forssén · H. T. Johansson
We make ab initio predictions for the A = 6 nuclear level scheme based on two- and three-nucleon interactions up to next-to-next-to-leading order in chiral effective field theory ( $χ$ EFT). We utilize eigenvector continuation and Bayesian methods to quantify uncertainties stemming from the many-body method, the $χ$ EFT truncation, and the low-energy constants of the nuclear interaction. The construction and validation of emulators is made possible via the development of JupiterNCSM -- a new M-scheme no-core shell model code that uses on-the-fly Hamiltonian matrix construction for efficient, single-node computations up to $N_{max} = 10$ for $^{6} Li$ . We find a slight underbinding of $^{6} He$ and $^{6} Li$ , although consistent with experimental data given our theoretical error bars. As a result of incorporating a correlated $χ$ EFT-truncation errors we find more precise predictions (smaller error bars) for separation energies: $S_{d} (^{6} Li) = 0.89 \pm 0.44$ MeV, $S_{2 n} (^{6} He) = 0.20 \pm 0.60$ MeV, and for the beta decay Q-value: $Q_{β^{-}} (^{6} He) = 3.71 \pm 0.65$ MeV. We conclude that our error bars can potentially be reduced further by extending the model space used by JupiterNCSM.
Comments:
13 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Data Analysis, Statistics and Probability (physics.data-an)
arXiv:
2108.13313 [pdf]
PRC(2022)·31 citations
10
[Submitted on 27 Aug 2021] (cross-list from hep-lat)
Finite-density lattice QCD and sign problem: current status and open problems
Keitaro Nagata🇯🇵
This an English translation of a review of finite-density lattice QCD. The original version in Japanese appeared in Soryushiron Kenkyu Vol 31 (2020) No. 1.
Comments:
164pages: Translated from Japanese to English by Masanori Hanada and Etsuko Itou. This an English translation of a review of finite-density lattice QCD. The original version in Japanese appeared in Soryushiron Kenkyu Vol 31 (2020) No. 1
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2108.12423 [pdf]
PPNP(2022)·233 citations
11
[Submitted on 27 Aug 2021] (cross-list from quant-ph)
Path integrals, complex probabilities and the discrete Weyl representation
Wayne Polyzou🇺🇸
A discrete formulation of the real-time path integral as the expectation value of a functional of paths with respect to a complex probability on a sample space of discrete valued paths is explored. The formulation in terms of complex probabilities is motivated by a recent reinterpretation of the real-time path integral as the expectation value of a potential functional with respect to a complex probability distribution on cylinder sets of paths. The discrete formulation in this work is based on a discrete version of Weyl algebra that can be applied to any observable with a finite number of outcomes. The origin of the complex probability in this work is the completeness relation. In the discrete formulation the complex probability exactly factors into products of conditional probabilities and exact unitarity is maintained at each level of approximation. The approximation of infinite dimensional quantum systems by discrete systems is discussed. Applications to scattering theory and quantum field theory are illustrated.
Comments:
56 pages, 14 figures, expanded - revised text, minor typos corrected
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2108.12494 [pdf]
J.Phys.A(2024)·6 citations
12
[Submitted on 27 Aug 2021] (cross-list from hep-ph)
Mass Spectra of One or Two Heavy Quark Mesons and Diquarks within a Nonrelativistic Potential Model
L.X. Gutiérrez-Guerrero🇲🇽 · A. Alfaro🇲🇽 · A. Raya🇲🇽
In this article, the mass spectra of mesons with one or two heavy quarks and their diquarks partners are estimated within a non-relativistic framework by solving Schrödinger equation with an effective potential inspired by a symmetry preserving Poincaré covariant vector-vector contact interaction model of quantum chromodynamics. Matrix Numerov method is implemented for this purpose. In our survey of mesons with heavy quarks, we fix the model parameter to the masses of ground-states and then extend our calculations for radial excitations and diquarks. The potential model used in this work gives results which are in good agreement with experimental data and other theoretical calculations.
Comments:
15 pages, 5 figures, 6 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.12532 [pdf]
Int.J.Mod.Phys.A(2021)·12 citations
13
[Submitted on 29 Aug 2021] (cross-list from hep-ph)
Splitting of elliptic flow in non-central relativistic heavy-ion collisions
Zhengyu Chen🇨🇳 · Zeyan Wang🇨🇳 · Carsten Greiner🇩🇪 · Zhe Xu🇨🇳
We predict a new effect due to the presence of the global vorticity in non-central relativistic heavy-ion collisions, namely a splitting of the elliptic flow parameter $v_{2}$ at non-zero rapidity. The size of the splitting is proposed as a new observable that can be used to constrain the initial vortical configuration of the produced QCD matter in experiments. The new findings are demonstrated by numerical calculations employing the parton cascade model, Boltzmann Approach of MultiParton Scatterings (BAMPS), for non-central Au + Au collisions at $s_{N N} = 200 G e V$ .
Comments:
6 pages, 6 figures; add a passage in the end, add references
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.12735 [pdf]
7 citations
14
[Submitted on 29 Aug 2021] (cross-list from hep-ph)
Inverse magneto-rotational catalysis and the phase diagram of a rotating hot and magnetized quark matter
N. Sadooghi🇮🇷 · S. M. A. Tabatabaee🇮🇷 · F. Taghinavaz🇮🇷
We study the properties of a hot and magnetized quark matter in a rotating cylinder in the presence of a constant magnetic field. To do this, we solve the corresponding Dirac equation using the Ritus eigenfunction method. This leads to the energy dispersion relation, Ritus eigenfunctions, and the quantization relation for magnetized fermions. To avoid causality-violating effects, we impose a certain global boundary condition, and study its effect, in particular, on the energy eigenmodes and the quantization relations of fermions. Using the fermion propagator arising from this method, we then solve the gap equation at zero and nonzero temperatures. At zero temperature, the dynamical mass $m ˉ$ does not depend on the angular frequency, as expected. We thus study its dependence on the distance $r$ relative to the axis of rotation and the magnetic field $B$ , and explore the corresponding finite size effect for various couplings $G$ . We then consider the finite temperature case. The dependence of $m ˉ$ on the temperature $T$ , magnetic field $B$ , angular frequency $Ω$ , and distance $r$ for various $G$ is studied. We show that $m ˉ$ decreases, in general, with $B$ and $Ω$ . This is the ''inverse magneto-rotational catalysis (IMRC)'' or the ''rotational magnetic inhibition'', previously discussed in the literature. To explore the evidence of this effect in the phase diagrams of our model, we examine the phase portraits of the critical temperature $T_{c}$ as well as the critical angular frequency $Ω_{c}$ with respect to $G, B, Ω$ , and $r$ as well as $G, B, T$ , and $r$ , respectively. We show that $T_{c}$ and $Ω_{c}$ decrease, in particular, with $B$ . This is interpreted as clear evidence for IMRC.
Comments:
23 pages, 12 figures, 5 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2108.12760 [pdf]
PRD(2021)·47 citations
15
[Submitted on 30 Aug 2021] (cross-list from astro-ph.HE)
Relativistic hybrid stars in light of the NICER PSR J0740+6620 radius measurement
Jia Jie Li (Southwest U., Chongqing)🇨🇳 · Armen Sedrakian (FIAS, Frankfurt)🇩🇪 · Mark Alford (Washington U., St. Louis)🇺🇸
We explore the implications of the recent radius determination of PSR J0740+6620 by the NICER experiment combined with the neutron skin measurement by the PREX-II experiment and the associated inference of the slope of symmetry energy, for the structure of hybrid stars with a strong first-order phase transition from nucleonic to quark matter. We combine a covariant density-functional nucleonic equation of state (EOS) with a constant-speed-of-sound EOS for quark matter. We show that the radius and tidal deformability ranges obtained from GW170817 can be reconciled with the implication of the PREX-II experiment if there is a phase transition to quark matter in the low-mass compact star. In the high-mass segment, the EoS needs to be stiff to comply with the large-radius inference for PSR J0740+6620 and J0030+0451 with masses $M ≃ 2 M_{⊙}$ and $M ≃ 1.4 M_{⊙}$ . We show that twin stars are not excluded, but the mass and radius ranges (with $M \geq M_{⊙}$ ) are restricted to narrow domains $Δ M_{twin} ≲ 0.05 M_{⊙}$ and $Δ R_{twin} \sim 1.0$ ~km. We also show that the existence of twin configurations is compatible with the light companion in the GW190814 event being a hybrid star in the case of values of the sound-speed square $s = 0.6$ and $s = 1/3$ .
Comments:
7 pages and 4 figures; matches published version
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.13071 [pdf]
PRD(2021)·68 citations
16
[Submitted on 30 Aug 2021] (cross-list from hep-ph)
A new approach to semi-inclusive deep-inelastic scattering with QED and QCD factorization
Tianbo Liu🇨🇳 · W. Melnitchouk🇺🇸 · Jian-Wei Qiu🇺🇸 · N. Sato🇺🇸
We present the details of a new factorized approach to semi-inclusive deep-inelastic scattering which treats QED and QCD radiation on equal footing, and provides a systematically improvable approximation to the extraction of transverse momentum dependent parton distributions. We demonstrate how the QED contributions can be well approximated by collinear factorization, and illustrate the application of the factorized approach to QED radiation in inclusive scattering. For semi-inclusive processes, we show how radiation effects prevent a well-defined "photon-nucleon" frame, forcing one to use a two-step process to account for the radiation. We illustrate the utility of the new method by explicit application to the spin-dependent Sivers and Collins asymmetries.
Comments:
55 pages, 23 figures, accepted for publication in J. High Energy Phys
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.13371 [pdf]
JHEP(2021)·30 citations

Affiliations

first authorsco-authorsvia INSPIRE