Chinese Physics C

Reaction rate of the radiative p¹²C capture in the modified potential cluster model

S. B. Dubovichenko, N. A. Burkova, A. S. Tkachenko, A. Samratova

Published:

Abstract:
The astrophysical S-factor of the ¹²C(p,γ₀)¹³N reaction at energies from 25 keV to 5 MeV within the framework of a modified potential cluster model with forbidden states is considered. The experimental phase shifts resonant

\begin{document}$ {\delta _{^2{S_{1/2}}}} $\end{document}

,

\begin{document}$ {\delta _{^2{P_{3/2}}}} $\end{document}

, and non-resonant

\begin{document}$ {\delta _{^2{D_{3/2}}}} $\end{document}

at the energies up to E_c.m. =3 MeV are reproduced with high accuracy, which provides the appropriate agreement with the experimental data for the S-factor of 1950 -2023 years. Two sets of asymptotic constant are used: Set I refers to C_w = 1.30(2), and Set II refers to C_w = 1.37(1). Set I leads to the astrophysical factor S(25) = 1.34 ± 0.02 keV·b, which is in agreement with data by Skowronski et al., 2023 – 1.34 ± 0.09 keV·b; Set II gives S(25) = 1.49 ± 0.02 keV·b, which is in agreement with data by Kettner et al., 2023 – 1.48 ± 0.09 keV·b. The reaction rates of ¹²C(p,γ₀)¹³N at temperatures T₉ from 0.001 to 10 are calculated. The detailed comparison with some models, the R-matrix approach, and NACRE II data for reaction rates is considered.

The Fused Model of Alternating Spin Chain from ABJM Theory

Nan Bai, Fan Feng, Mao-Zhong Shao

Published:

Abstract:
In this paper we give an algebraic construction of the fused model for ABJM spin chain and find the corresponding boost operator. We also investigate the open spin Hamiltonian for fused model and point out the general common structures of the boundary terms.

Predictions for the synthesis of new superheavy nuclei with ²⁵²Cf target

Ming-Hao Zhang, Ying Zou, Mei-Chen Wang, Qing-Lin Niu, Gen Zhang, Feng-Shou Zhang

Published:

Abstract:
The

\begin{document}$ ^{252} {\rm{Cf}}$\end{document}

isotope produced at Oak Ridge National Laboratory is a promising target material for the synthesis of new superheavy nuclei through fusion reaction experiments. Within the framework of the dinuclear system model, the reaction systems with the

\begin{document}$ ^{252} {\rm{Cf}}$\end{document}

target and the

\begin{document}$ ^{48} {\rm{Ca}}$\end{document}

,

\begin{document}$ ^{45} {\rm{Sc}}$\end{document}

,

\begin{document}$ ^{50} {\rm{Ti}}$\end{document}

,

\begin{document}$ ^{51} {\rm{V}}$\end{document}

,

\begin{document}$ ^{54} {\rm{Cr}}$\end{document}

,

\begin{document}$ ^{55} {\rm{Mn}}$\end{document}

projectiles are investigated for the synthesis of new isotopes

\begin{document}$ ^{295-297} {\rm{Og}}$\end{document}

,

\begin{document}$ ^{292-294} {\rm{119}}$\end{document}

,

\begin{document}$ ^{297-299} {\rm{120}}$\end{document}

,

\begin{document}$ ^{298-300} {\rm{121}}$\end{document}

,

\begin{document}$ ^{301-303} {\rm{122}}$\end{document}

and

\begin{document}$ ^{302-304} {\rm{123}}$\end{document}

. The decreasing trend of the maximal evaporation residue cross sections with the increasing proton number of the compound nucleus are discussed in the capture, fusion and survival stages. Additionally, the radioactive beam-induced reactions based on the

\begin{document}$ ^{252} {\rm{Cf}}$\end{document}

target are investigated to reach the predicted neutron shell closure N = 184, with the maximal evaporation residue cross section predicted to be 21 fb for synthesizing

\begin{document}$ ^{302} {\rm{Og}}$\end{document}

. The predicted results fall below the current detection limitation, indicating the necessity for advancement in both accelerator and detection techniques, as well as exploration of alternative reaction mechanisms.

Off-equatorial deflections and gravitational lensing. II. In general stationary and axisymmetric spacetimes

Xinguang Ying, Junji Jia

Published:

Abstract:
In this work, we develop a general perturbative procedure to find the off-equatorial plane deflections in the weak deflection limit in general stationary and axisymmetric spacetimes, allowing the existence of the generalized Carter constant. Deflections of both null and timelike rays, with the finite distance effect of the source and detector taken into account, are obtained as dual series of

\begin{document}$M/r_0$\end{document}

and

\begin{document}$r_0/r_{s,d}$\end{document}

. These deflections allow a set of exact gravitational lensing equations from which the images' apparent angular positions are solved. The method and general results are then applied to the Kerr-Newmann, Kerr-Sen, and rotating Simpson-Visser spacetimes to study the effect of the spin and characteristic (effective) charge of the spacetimes and the source altitude on the deflection angles and image apparent angles. It is found that, in general, both the spacetime spin and charge only affect the deflections from the second non-trivial order, while the source altitude influences the deflection from the leading order. Because of this, it is found that, in gravitational lensing in realistic situations, it is hard to measure the effects of the spacetime spin and charge from the images' apparent locations. We also presented the off-equatorial deflections in the rotating Bardeen, Hayward, Ghosh, and Tinchev black hole spacetimes.

Thermodynamic Topology of Kiselev-AdS Black Holes within f (R, T) gravity

Saeed Noori Gashti, Mohammad Ali S. Afshar, Mohammad Reza Alipoury, Yassine Sekhmani, Jafar Sadeghi, Javlon Rayimbaeva

Published:

Abstract:
In this paper, we investigate the topological charge and the conditions for the existence of the photon sphere (PS) in Kiselev-AdS black holes within

\begin{document}$f(R, T)$\end{document}

gravity. Furthermore, we establish their topological classifications. We employ two different methods based on Duan’s topological current ϕ-mapping theory viz analysis of temperature and the generalized Helmholtz free energy methods to study the topological classes of our black hole. By considering the mentioned black hole, we discuss the critical and zero points (topological charges and topological numbers) for different parameters. Our findings reveal that the Kiselev parameter ω and the

\begin{document}$f(R, T)$\end{document}

gravity parameter γ influence the number of topological charges of black holes, leading to novel insights into topological classifications. We observe that for given values of the free parameters, there exist total topological charges (

\begin{document}$Q_{total} = -1$\end{document}

) for T-method and total topological numbers (

\begin{document}$W = +1$\end{document}

) for the generalized Helmholtz free energy method. Our research findings elucidate that, in contrast to the scenario where

\begin{document}$\omega = 1/3$\end{document}

, in other cases, increasing the parameter γ increases the number of total topological charges for the black hole. Interestingly, for the phantom field (

\begin{document}$\omega = -4/3$\end{document}

), we observed that decreasing the parameter γ increases the number of topological charges. Additionally, we study the results for the photon sphere. The studied models reveal that the simultaneous presence of γ and ω effectively expands the permissible range for γ. In other words, the model can exhibit black hole behavior over a larger domain. Additionally, it is evident that with the stepwise reduction of ω, the region covered by singularity also diminishes and becomes more restricted. However, An interesting point about all three ranges is the elimination of the forbidden region in this model. In other words, it appears that in this model and the investigated areas, there is no region where both the ϕ function and the metric function simultaneously lack solutions. Also, at the end, we fully checked the curvatures singularities, and energy conditions for the mentioned black hole.

Critical collapse in asymptotically anti-de Sitter spacetime

Li-Jie Xin, Cheng-Gang Shao

Published:

Abstract:
We investigate the critical collapse of spherically symmetric scalar fields in asymptotically anti-de Sitter spacetime, focusing on two scenarios: real and complex scalar fields with potentials. By fine-tuning the amplitude of the initial scalar field under different cosmological constants, we find a linear relationship between the critical amplitude of the first collapse and the cosmological constant in both scenarios. Furthermore, we observe that the slope of this linear relationship varies linearly with the coupling strength.

Bremsstrahlung emission from nucleon-nucleus reactions in dense medium of compact stars

Sergei P. Maydanyuk, Ju-Jun Xie, Kostiantyn A. Shaulskyi

Published:

Abstract:
Bremsstrahlung photons emitted during nucleon-nucleus reactions in compact star are investigated. Influence of density of stellar medium on intensity of emission is studied at first time in quantum approach. Bremsstrahlung model is generalized, where new term describing influence of stellar medium is added to interactions between nucleons of nucleus (in frameworks of nuclear model of deformed oscillatoric shells). Polytropic EOS, Chandrasekar EOS and Harrison-Wheeler EOS are applied for calculations. Unified EOS of neutron-star matter of Haensel and Potekhin based on FPS an SLy EOSs is used for tests. Bremsstrahlung calculations are tested on existed measurements of bremsstrahlung in the scattering of protons off the ¹⁹⁷Au nuclei at energy of proton beam of

\begin{document}$ E_{\rm p}=190 $\end{document}

MeV. Many properties of bremsstrahlung emitted from nuclear processes in stellar medium of compact stars are studied at first time. In particular, the spectra of photons in the scattering of protons and neutrons off ⁴He, ⁸Be, ¹²C, ¹⁶O, ²⁴Mg, ⁴⁰Ca, ⁵⁶Fe are estimated in dependence on density of stellar medium. Medium of white dwarfs has small influence on the bremsstrahlung emission from nuclear processes, while bremsstrahlung emission is intensive in neutron stars and it is changed essentially in dependence on stellar density and structure.

Off-equatorial deflections and gravitational lensing. I. In Kerr spacetime and effect of spin

Tingyuan Jiang, Xiaoge Xu, Junji Jia

Published:

Abstract:
This paper investigates off-equatorial plane deflections and gravitational lensing of both null signals and massive particles in Kerr spacetime in the weak deflection limit, with the finite distance effect of the source and detector taken into account. This is the effect caused by the fact that both the source and detector are located at finite distances from the lens, while many researchers often use the deflection angle for infinite distances from sources and detectors. The deflection in both the

\begin{document}$ \phi $\end{document}

and

\begin{document}$ \theta $\end{document}

directions is computed as power series of

\begin{document}$ M/r_0 $\end{document}

and

\begin{document}$ r_0/r_{\mathrm{s,d}} $\end{document}

, where

\begin{document}$ M,\,r_{\mathrm{s,d}} $\end{document}

are the spacetime mass and source and detector radii respectively, and

\begin{document}$ r_0 $\end{document}

is the minimal radial coordinate of the trajectory. The coefficients of these series are simple trigonometric functions of

\begin{document}$ \theta_ \mathrm{e} $\end{document}

, the extreme value of the

\begin{document}$ \theta $\end{document}

coordinate of the trajectory. A set of exact gravitational lensing equations is used to solve for

\begin{document}$ r_0 $\end{document}

and

\begin{document}$ \theta_ \mathrm{e} $\end{document}

for given deviation angles

\begin{document}$ \delta\theta $\end{document}

and

\begin{document}$ \delta\phi $\end{document}

of the source, and two lensed images are always obtained. The apparent angles and their magnifications of these images, and the time delays between them are solved and their dependence on various parameters, especially spacetime spin

\begin{document}$ \hat{a} $\end{document}

are analyzed in great detail. It is found that there generally exist two critical spacetime spin values that separate the case of test particles reaching the detector from different sides of the

\begin{document}$ z $\end{document}

axis from the cases in which the images appear from the same side in the celestial plane. Three potential applications of these results are discussed.

Revisiting the alpha-decay reduced width of the lightest uranium isotope ²¹⁴U

Shuangshuang Zhang, Yongjia Wang, Xiaotao He

Published:

Abstract:
Background: The lightest uranium isotope

\begin{document}$ {\rm^{214}U} $\end{document}

has been produced using the Heavy Ion Research Facility in Lanzhou, China. It is found that the α-decay reduced width (