Nuclear Theory·nucl-th

Wednesday·May 17, 2023

15 papers—10 primary·5 cross-listed

01
[Submitted on 16 May 2023]
On cancellation of non-adiabatic and off-shell effects in the antiproton annihilation in deuteron
O.D. Dalkarov🇷🇺 · V.A. Karmanov🇷🇺 · E.A. Kupriyanova🇷🇺
As known, some approximate approaches to the hadron scattering from nuclei work rather well far beyond the limits of their applicability. This was explained by cancellation of the contributions (non-adiabatic and off-shell effects) omitted in these approaches. Moreover, in some cases (in particular, for the reaction $p ˉ d \to e^{+} e^{-} n$ ) this cancellation allowed to derive rather simple analytical formula for the reaction amplitude. Solving the Faddeev equations, we confirm numerically this formula and, hence, the cancellations.
Comments:
18 pages, 8 figures, accepted in Eur. Phys. Journ. A
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2305.09100 [pdf]
EPJA(2023)·0 citations
02
[Submitted on 16 May 2023]
Global spin alignment of vector mesons and strong force fields in heavy- ion collisions
Jinhui Chen🇨🇳 · Zuo-Tang Liang🇨🇳 · Yu-Gang Ma🇨🇳 · Qun Wang🇨🇳
A perspective for the Global spin alignment of vector mesons and strong force fields in heavy-ion collisions is provided in this short report.
Comments:
4 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2305.09114 [pdf]
Sci.Bull.(2023)·42 citations
03
[Submitted on 16 May 2023]
Statistical approach of nuclear multifragmentation with realistic nuclear equation of state
S. Mallik
In this work, Canonical Thermodynamical model for nuclear multifragmentation has been updated with realistic nuclear equation of state. Mass distribution, intermediate mass fragment multiplicity as well as isospin sensitive observables have been investigated with semi-microscopic approach of determining nuclear binding and excitation energies. Production of neutron rich isotopes as well as isoscaling and isobaric yield ratio parameters have been significantly modified due to inclusion of this realistic nuclear equation of state.
Comments:
8 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2305.09158 [pdf]
PRC(2023)·4 citations
04
[Submitted on 16 May 2023]
Evidence of bicluster structure in the ground state of $^{20}$ Ne
Y. Yamaguchi · W. Horiuchi · N. Itagaki
We explore the structure of the ground state of $^{20}$ Ne by investigating various density profiles. Four candidates for the ground state configurations, (a) $j$ - $j$ coupling and (b) SU(3) shell model and (c) $5 α$ and (d) $^{16} O + α$ cluster model configurations are generated by utilizing the antisymmetrized quasicluster model. A high-energy reaction theory, the Glauber model, relates these one-body density distributions and reaction observables. The angular distributions of the elastic scattering cross sections clearly distinguish these configurations and tell which is the most plausible one: The ground state of $^{20}$ Ne favors a 16+4 nucleon bi-cluster structure. A comprehensive investigation of other electric observables also supports this conclusion.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2305.09182 [pdf]
PRC(2023)·12 citations
05
[Submitted on 16 May 2023]
Odd-even shape staggering and kink structure of charge radii of Hg isotopes by the deformed relativistic Hartree-Bogoliubov theory in continuum
Myeong-Hwan Mun · Seonghyun Kim · W. Y. So · Soonchul Choi · Eunja Ha · Myung-Ki Cheoun
We examined the shape staggering of relative charge radii in $^{180 - 186}$ Hg isotopes, which was first measured in 1977 and recently confirmed using advanced spectroscopy techniques. To understand the nuclear structure underlying this phenomenon, we employed the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). Our analysis revealed that the shape staggering can be attributed to nuclear shape transition in the Hg isotopes. Specifically, we demonstrated that prolate shapes of $^{181, 183, 185}$ Hg lead to an increase in the charge radii compared to oblate shapes of $^{180, 182, 184, 186}$ Hg isotopes. We explained the nuclear shape staggering in terms of the evolution of occupation probability (OP) of $ν 1 i_{13/2}$ , $ν 1 h_{9/2}$ , $π 1 h_{9/2}$ , and $π 3 s_{1/2}$ states. Additionally, we clarified the kink structure of the charge radii in the Hg isotopes near $N = 126$ magic shell does not come from the change of the OP of $π 1 h_{9/2}$ state, but mainly by the increase of the OPs of $ν 1 i_{11/2}$ and $ν 2 g_{9/2}$ states.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2305.09205 [pdf]
PLB(2023)·30 citations
06
[Submitted on 16 May 2023]
Production of nuclei and hypernuclei in pion-induced reactions near threshold energies
Apiwit Kittiratpattana🇩🇪 · Tom Reichert🇩🇪 · Nihal Buyukcizmeci🇹🇷 · Alexander Botvina🇩🇪 · Ayut Limphirat🇹🇭 · Christoph Herold🇹🇭 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
The Ultra-relativistic Quantum Molecular Dynamics model is employed to simulate $π^{-} + C$ and $π^{-} + W$ collisions at p $_{lab} = 1.7$ GeV motivated by the recent HADES results. By comparing the proton and $Λ$ transverse momentum spectra, it was observed that the data and transport model calculation show a good agreement, if cluster formation is included to obtain the free proton spectra. Predictions of light cluster ( $d$ , $t$ , $^{3}$ He, $^{4}$ He, as well as $_{Λ}^{3}$ H and $Ξ$ N) multiplicities and spectra are made using a coalescence mechanism. The resulting multiplicities suggest that the pion beam experiment can produce a substantial amount of $_{Λ}^{3}$ H, especially in $π^{-} + W$ collisions due to the stopping of the $Λ$ inside the large tungsten nucleus. The findings are supplemented by a statistical multi-fragmentation analysis suggesting that even larger hyper-fragments are produced copiously. It is suggested that even double strange hypernuclei are in reach and might be studied in more detail using a slightly higher pion beam momentum.
Comments:
9 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2305.09208 [pdf]
PRC(2024)·5 citations
07
[Submitted on 16 May 2023]
Configuration mixing and intertwined quantum phase transitions in odd-mass niobium isotopes
N. Gavrielov
Nuclei in the $Z \approx 40, N \approx 60$ region have one of the most complicated structural evolution across the nuclear chart, with coexisting shapes arising from different mixed configurations. In such a region, it is difficult to investigate odd-mass nuclei. In this paper a new algebraic framework is introduced, the interacting boson-fermion model with configuration mixing. Using this framework, with a boson core and a proton in the $1 f_{5/2}, 2 p_{3/2}, 2 p_{1/2}, 1 g_{9/2}$ orbits, a calculation is carried out to understand the structural evolution of the odd-mass niobium isotopes $(Z = 41)$ with neutron number 52-62. The calculated results are compared to energy levels, two neutron separation energies, $E 2$ and $M 1$ transition rates, and to quadrupole and magnetic moments. The detailed analysis discloses the effects of an abrupt crossing of states between normal and intruder configurations (Type II QPT), which is accompanied by a gradual evolution from spherical- to deformed-core shapes within the intruder configuration (Type I QPT), where both types of QPTs occur around the critical point of neutron number 60. The identification of both types of QPTs in the same chain of isotopes provides an empirical manifestation of intertwined quantum phase transitions (IQPTs) in odd-mass nuclei and the relevance of IQPTs to the niobium chain.
Comments:
20 pages, 24 figures, 2 tables. arXiv admin note: text overlap with arXiv:2210.00441
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2305.09376 [pdf]
PRC(2023)·18 citations
08
[Submitted on 16 May 2023]
Synthesis of elements in compact stars in pycnonuclear reactions with Carbon isotopes: Quasibound states versus states of zero-points vibrations
Sergei P. Maydanyuk (1,2) · Gyorgy Wolf (1) · Kostiantyn A. Shaulskyi (2) ((1) Wigner Research Center for Physics, Budapest, Hungary, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine)
(1) Purpose: Conditions of formation of compound nuclear system needed for synthesis of heavy nuclei in pycnonuclear reactions in compact stars are studied on a quantum mechanical basis. (2) Methods: Method of multiple internal reflections is generalized for pycnoreactions in compact stars with new calculations of quasibound spectra and spectra of zero-point vibrations. (3) Results: Peculiarities of the method are analyzed for reaction with isotopes of Carbon. The developed method takes into account continuity and conservation of quantum flux (describing pycnonuclear reaction) inside the full spacial region of reaction including nuclear region. This gives appearance of new states (called as quasibound states), in which compound nuclear systems of Magnesium are formed with the largest probability. These states have not been studied yet in synthesis of elements in stars. Energy spectra of zero-point vibrations and spectra of quasibound states are estimated with high precision for reactions with isotopes of Carbon. At the first time influence of plasma screening on quasibound states and states of zero-point vibrations in pycnonuclear reactions has been studied. (4) Conclusion: The probability of formation of compound nuclear system in quasibound states in pycnonuclear reaction is essentially larger than the probability of formation of this system in states of zero-point vibrations studied by Zel'dovich and followers. So, synthesis of Magnesium from isotopes of Carbon is more probable through the quasibound states than through the states of zero-point vibrations in compact stars. Energy spectra of zero-point vibrations are changed essentially after taking plasma screening into account. Analysis shows that from all studied isotopes of Magnesium only \isotope[24]{Mg} is stable after synthesis at energy of relative motion of 4.881~MeV of incident nuclei \isotope[12]{C}.
Comments:
15 pages, 4 captured figures, 4 captured tables. arXiv admin note: text overlap with arXiv:2205.13895
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2305.09389 [pdf]
Universe(2023)·5 citations
09
[Submitted on 16 May 2023]
Energy and Angle Dependence of Neutrino Scattering Rates in Proto-Neutron Star and Supernova Matter within Skyrme RPA
Mingya Duan🇫🇷 · Michael Urban🇫🇷
Supernova explosions are the most powerful neutrino sources. The neutrino emission is also the dominating cooling mechanism for a proto-neutron star, whose interior is mainly composed of extremely dense and hot nuclear matter. Neutrino transport is an essential part of the simulation of these phenomena, and modern codes are able to implement inelastic neutrino scattering and also to some extent its angle distribution. We therefore study the energy and angle dependence of neutrino scattering rates in proto-neutron star and supernova matter with the full Skyrme RPA response functions. We confirm earlier findings obtained in the Landau approximation that the RPA reduces neutrino scattering, but the detailed differential scattering rates in hot and dense matter depend sensitively on the adopted interaction. The scattering angle distribution is different for different interactions because it depends strongly on the neutron Fermi velocity. We also find that many Skyrme interactions present an unphysical feature that the Fermi velocity of neutrons exceeds the speed of light already at relatively low densities.
Comments:
18 pages, 9 figures; v2: minor changes; v3: missing terms in Eqs. (20), (A2)-(A4) added
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2305.09499 [pdf]
PRC(2023)·12 citations
10
[Submitted on 16 May 2023]
Chiral perturbation theory of the hyperfine splitting in (muonic) hydrogen
Franziska Hagelstein🇩🇪 · Vadim Lensky🇩🇪 · Vladimir Pascalutsa🇩🇪
The ongoing experimental efforts to measure the hyperfine transition in muonic hydrogen prompt an accurate evaluation of the proton-structure effects. At the leading order in $α$ , which is $O (α^{5})$ in the hyperfine splitting (hfs), these effects are usually evaluated in a data-driven fashion, using the empirical information on the proton electromagnetic form factors and spin structure functions. Here we perform a first calculation based on the baryon chiral perturbation theory (B $χ$ PT). At leading orders it provides a prediction for the proton polarizability effects in hydrogen (H) and muonic hydrogen ( $μ$ H). We find large cancellations among the various contributions leading to, within the uncertainties, a zero polarizability effect at leading order in the B $χ$ PT expansion. This result is in significant disagreement with the current data-driven evaluations. The small polarizability effect implies a smaller Zemach radius $R_{Z}$ , if one uses the well-known experimental $1 S$ hfs in H or the $2 S$ hfs in $μ$ H. We, respectively, obtain $R_{Z} (H) = 1.010 (9)$ fm, $R_{Z} (μ H) = 1.040 (33)$ fm. The total proton-structure effect to the hfs at $O (α^{5})$ is then consistent with previous evaluations; the discrepancy in the polarizability is compensated by the smaller Zemach radius. Our recommended value for the $1 S$ hfs in $μ H$ is $182.640 (18) meV .$
Comments:
22 pages, 11 figures, 3 tables, typo in Eq. (13) corrected, references updated
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Atomic Physics (physics.atom-ph)
arXiv:
2305.09633 [pdf]
EPJC(2023)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE