## 2023 Vol. 47, No. 8

Display Method: |

2023, 47(8): 083101. doi: 10.1088/1674-1137/acd364

**Abstract:**

In this study, we compute the correlation functions of Wilson(-'t Hooft) loops with chiral primary operators in the

2023, 47(8): 084001. doi: 10.1088/1674-1137/acd366

**Abstract:**

Charge-changing cross section (

2023, 47(8): 084002. doi: 10.1088/1674-1137/acd83d

**Abstract:**

The neutron deficient Xe nuclei with

*A*

*γ*-ray spectroscopy. High spin states in

*p*2

*n*)

*γ*-transitions have been found and placed appropriately in the level scheme. A theoretical study using the triaxial projected shell model (TPSM) approach suggests that the first bandcrossing is due to the alignment of two neutrons, and a parallel band tracking the yrast configuration is the

*γ*-band built on the two-quasiparticle state. Enhanced

*E*1 transition rates measured between opposite parity bands involving

*νh*

*ν*

*d*

*j*= Δ

*l*= 3 indicate the presence of octupole correlation in this nucleus.

2023, 47(8): 084101. doi: 10.1088/1674-1137/acd680

**Abstract:**

The tensor force and pairing correlation effects on the two-proton radioactivity of

2023, 47(8): 084102. doi: 10.1088/1674-1137/acd9be

**Abstract:**

In the first Born approximation, we study the reactions

2023, 47(8): 084103. doi: 10.1088/1674-1137/acd682

**Abstract:**

Theoretical modeling of nucleus-nucleus collisions is often based on the nucleus-nucleus potential. One of the advanced methods for constructing this potential is the semi-microscopical double-folding model with M3Y-Paris NN-forces. Proton and neutron densities are significant components of this model. The correct nucleon density (ND) must reproduce the experimental nuclear charge density (NCD). However, those who deal with modeling the fusion process typically disregard this circumstance. We aim to achieve a good description of both the nuclear charge density and above-barrier fusion cross sections of even-even light nuclei with

^{12}C,

^{16}O, and

^{40}Ca, abbreviated as FE-density (Fermi+exponential). We carefully compare the NCDs resulting from different versions of NDs with the experimental NCDs. After finding the nucleus-nucleus potential using the double-folding model with the density dependent M3Y-Paris NN-forces and FE densities, we evaluate the above-barrier fusion cross sections for five reactions,

^{12}C+

^{12}C,

^{12}C+

^{16}O,

^{16}O+

^{16}O,

^{16}O+

^{40}Ca, and

^{40}Ca+

^{40}Ca, for which experimental data are available. The cross sections are calculated using two approaches: a) the barrier penetration model and b) the trajectory model with surface friction (TM). To find the transmission coefficients for the TM, the Langevin equations are employed. For all considered reactions, our TM typically reproduces the above-barrier experimental cross sections within 10−15%. The only adjustable parameter of the model, the optimal friction strength

^{12}C+

^{12}C,

^{12}C+

^{16}O, and

^{16}O+

^{16}O and approximately 15

^{16}O+

^{40}Ca and

^{40}Ca+

^{40}Ca. The latter findings are in reasonable agreement with the systematics found previously. Thus, the FE-recipe allows highly accurate and simultaneous reproduction of both the nuclear charge density and above-barrier fusion cross sections of five reactions involving

^{12}C,

^{16}O, and

^{40}Ca nuclei.

2023, 47(8): 084104. doi: 10.1088/1674-1137/acdb54

**Abstract:**

In this study, we improve the relations of the charge-radius difference of two isotopes by considering a term that relates to the proton number and the parity of the neutron number. The correction reduces the root-mean-squared deviation to 0.0041 fm for 651 nuclei with a neutron number larger than 20, in comparison with experimental data compiled in the CR2013 database. The improved relations are combined with local relations consisting of the charge radii of four neighboring nuclei. These combinations also prove to be efficient in describing and predicting nuclear charge radii and can reflect the structure evolutions of nuclei. Our predictions of 2467 unknown nuclear charge radii at competitive accuracy, which are calculated using these two types of relations, are tabulated in the Supplemental Material.

2023, 47(8): 084105. doi: 10.1088/1674-1137/acdb55

**Abstract:**

Within the framework of the modified potential cluster model with forbidden states, the total cross-sections of radiative

*n*

^{9}Be capture to the ground and five low-lying excited states are calculated at energies from 10

^{−2}eV up to 5 MeV. The thermal cross-section

*E*

_{x}from 7.371 MeV up to 10.570 MeV corresponding to the following states with

*E*

_{x}, MeV):

^{9}Be(

*n*,

*γ*

_{0+1+2+3+4+5})

^{10}Be reaction rates are calculated at temperatures from 0.001 to 10

*T*

_{9}. Contrary to the available data, we propose that the rise in the reaction rate near factor five at

*T*

_{9}>1 is mainly due to the first

*E*

_{R}= 0.559 MeV) resonance. We foresee this contrast as arising from different model approaches.

2023, 47(8): 084106. doi: 10.1088/1674-1137/acdc8b

**Abstract:**

Based on the magnetic monopole (MM) catalytic nuclear decay (Rubakov-Callan (RC) effect), we propose five new models to discuss the limit of the MM flux and the heating energy resources of white dwarfs (WDs) based on observations of 13 red giant branch (RGB) stars. We find that the number of MMs captured can reach a maximum value of

2023, 47(8): 084107. doi: 10.1088/1674-1137/acddd7

**Abstract:**

Data from the Large Hadron Collider on the charge balance function in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted within the framework of the HYDJET++ model. This model allows us to qualitatively reproduce the experimentally observed centrality dependence of the balance function widths at relatively low transverse momentum intervals due to the different charge creation mechanisms in soft and hard processes. However, a fully adequate description of the balance function in these intervals implies an essential modification of the model by including exact charge conservation via the canonical rather than the grand canonical ensemble. A procedure is proposed for introducing charge correlations into the thermal model without changing other model parameters. With increasing transverse momenta, the default model results describe the experimental data much better because the contribution of the soft component of the model is significantly reduced in these transverse momentum intervals. In practical terms, there is a transition to a single source of charge correlations, namely, charge correlations in jets in which exact charge conservation holds at each stage.

2023, 47(8): 085101. doi: 10.1088/1674-1137/acd681

**Abstract:**

This study investigates the echoes in axial gravitational perturbations in compact objects. Accordingly, we propose an alternative scheme of the finite difference method implemented in two coordinate systems, where the initial conditions are placed on the axis of the tortoise coordinate with appropriate boundary conditions that fully respect the causality. The scheme is then employed to study the temporal profiles of the quasinormal oscillations in the Schwarzschild black hole and uniform-density stars. When presented as a two-dimensional evolution profile, the resulting ringdown waveforms in the black hole metric are split into reflected and transmitted waves as the initial perturbations evolve and collide with the peak of the effective potential. Meanwhile, for compact stars, quasinormal oscillations might be characterized by echoes. Consistent with the causality arguments, the phenomenon is produced by the gravitational waves bouncing between the divergent potential at the star's center and the peak of the effective potential. The implications of the present study are also discussed herein.

2023, 47(8): 085102. doi: 10.1088/1674-1137/acd83e

**Abstract:**

In the electromagnetic channel, chaotic gravitational lensing is a peculiar phenomenon in strong gravitational lensing. In this study, we analyze the properties and emergence of chaotic gravitational lensing in the Manko-Novikov black hole spacetime. Aiming to better understand the underlying physics, we elaborate on the boundaries of the accessible region through analyses of the contours of the effective potentials. The latter is associated with the two roots of a quadratic equation. In particular, we explore its interplay with an ergoregion, which leads to specific features of the effective potentials, such as the emergence of a cuspy edge and the formation of a pocket, which serve as static constraints on the geodesics. Additionally, we investigate the properties of the radial and angular accelerations at the turning points in photon trajectories. The accelerations are further examined and may provide kinematic constraints on the geodesics, as argued herein. It is concluded that the onset of the chaotic lensing is significantly related to both constraints; as a result, an arbitrary slight deviation in the incident photon is significantly amplified during evolution through an extensive period, demonstrating the complexity in the highly nonlinear deterministic gravitational system.

2023, 47(8): 085103. doi: 10.1088/1674-1137/acd530

**Abstract:**

We investigate the photon sphere and marginally stable circular orbit of massive particles over the recently proposed regular black holes with sub-Planckian curvature and a Minkowskian core. We derive the effective potential for geodesic orbits and determine the radius of circular photon orbits, with an analysis of the stability of these orbits. We extend our analysis to the background of a compact massive object (CMO) without a horizon, whose mass is below the lowest bound for the formation of a black hole. For massive particles, marginally stable circular orbits become double-valued in the CMO phase. Through a comparison with Bardeen and Hayward black holes, we also find that the locations of the photon sphere and marginally stable circular orbit in the CMO phase with a Minkowskian core are evidently different from those in the CMO phase with a dS core, which potentially provides a way to distinguish between these two types of black holes by astronomical observation. Finally, we present the observational constraint on the deviation parameter for such regular black holes using observed data from the black hole M87*.

2023, 47(8): 085104. doi: 10.1088/1674-1137/acd9bf

**Abstract:**

We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden

2023, 47(8): 085105. doi: 10.1088/1674-1137/acda1c

**Abstract:**

We reconstruct the extragalactic dispersion measure – redshift (

2023, 47(8): 085106. doi: 10.1088/1674-1137/acdd60

**Abstract:**

In this paper we analyze and discuss 2D Jackiw-Teitelboim (JT) gravity coupled to primary fermion fields in asymptotically anti-de Sitter (AdS) spacetimes. We obtain a particular solution of the massless Dirac field outside the extremal black hole horizon and find the solution for the dilaton in JT gravity. As two dimensional JT gravity spacetime is conformally flat, we calculate the two point correlators of primary fermion fields under the Weyl transformations. The primary goal of this work is to present a standard technique, called

*resolvent*, rather than using CFT methods. We redefine the fields in terms of the conformal factor as fermion fields and use the resolvent technique to derive the renormalized entanglement entropy for massless Dirac fields in JT gravity.

2023, 47(8): 085107. doi: 10.1088/1674-1137/acdc8a

**Abstract:**

Recent developments in the exploration of the universe suggest that it is in an accelerated phase of expansion. Accordingly, our study aims to probe the current scenario of the universe with the aid of the reconstruction technique. The primary factor that describes cosmic evolution is the deceleration parameter. Here, we provide a physically plausible, newly defined model-independent parametric form of the deceleration parameter. Further, we constrain the free parameters through statistical MCMC analysis for different datasets, including the most recent Pantheon+. With the statistically obtained results, we analyze the dynamics of the model through the phase transition, EoS parameter, and energy conditions. Also, we make use of the tool Om diagnostic to test our model.

**ISSN** 1674-1137 **CN** 11-5641/O4

Original research articles, Ietters and reviews Covering theory and experiments in the fieids of

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- Particle and nuclear astrophysics
- Cosmology

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