## 2022 Vol. 46, No. 7

Display Method: |

2022, 46(7): 071001. doi: 10.1088/1674-1137/ac5fa2

**Abstract:**

By analyzing existing data on pseudoscalar charmonium decays, we obtain the ratio of the branching fractions of

2022, 46(7): 073101. doi: 10.1088/1674-1137/ac5c2d

**Abstract:**

According to gauge/gravity duality, we use an Einstein-Maxwell-dilaton (EMD) model to study the running coupling constant at finite chemical potential and magnetic field. First, we calculate the effect of temperature on the running coupling constant and find the results are qualitatively consistent with lattice guage theory. Subsequently, we calculate the effect of chemical potential and magnetic field on running coupling. It is found that the chemical potential and magnetic field both suppress the running coupling constant. However, the effect of the magnetic field is slightly larger than that of chemical potential for a fixed temperature. Compared with the confinement phase, the magnetic field has a large influence on the running coupling in the deconfinement phase.

2022, 46(7): 073102. doi: 10.1088/1674-1137/ac5db9

**Abstract:**

Using gauge/gravity duality, we investigate the string breaking and dissolution of two heavy quarks coupled to a light quark at finite temperature. It is found that three configurations of

*QQq*exist with the increase in separation distance for heavy quarks in the confined phase. Furthermore, string breaking occurs at the distance

*QQq*melts at a certain distance and then becomes free quarks. Finally, we compare the potential of

*QQq*with that of

*QQq*at high temperatures.

2022, 46(7): 073104. doi: 10.1088/1674-1137/ac5f9c

**Abstract:**

Based on the recent precise measurements by the BESIII collaboration for electron–positron annihilation into a neutron and antineutron pair, the effective form factors of the neutron were determined in the time-like region, and it was found that the effective form factors of the neutron are smaller than those of the proton. The effective form factors of the neutron show a periodic behaviour, similar to those of the proton. Here, a comparative analysis for Λ,

2022, 46(7): 073105. doi: 10.1088/1674-1137/ac600b

**Abstract:**

The two-body weak decays

*N*

_{c}=3, we determine nonfactorizable isospin amplitudes from the experimental data for these modes. Our results support the universality of the ratio of nonfactorizable isospin reduced amplitudes for these decays within experimental errors. To demonstrate that these systematics are not coincidental, we also plot our results w. r. t. this ratio.

2022, 46(7): 073106. doi: 10.1088/1674-1137/ac600c

**Abstract:**

In this study, we perform systematic estimations of the radiative decays of the charmed mesons in a modified relativistic quark model. Our estimations indicate that the branching ratios of the processes of

2022, 46(7): 073107. doi: 10.1088/1674-1137/ac62ca

**Abstract:**

The stellar energy loss rates due to the production of neutrino pairs

2022, 46(7): 074001. doi: 10.1088/1674-1137/ac5c2e

**Abstract:**

Using inclusive decays of

2022, 46(7): 073103. doi: 10.1088/1674-1137/ac5f9d

**Abstract:**

The entropy per rapidity

*π*,

*k*,

*p*, Λ, Ω, and

*π*,

*k*,

*p*, Λ, and

2022, 46(7): 074002. doi: 10.1088/1674-1137/ac5e93

**Abstract:**

Polarization transfer measurement plays an important role in the search for new physics processes in charmed baryon decays. The measurement of the

2022, 46(7): 074101. doi: 10.1088/1674-1137/ac5cb0

**Abstract:**

The interacting boson model with

*γ*-soft rotation. In this paper,

*γ*-softness are observed, in which the corresponding energy levels in the ground and quasi-

*γ*bands can be exactly degenerate and have a partial

*γ*-softness is not related to the classical

*γ*-softness can be used to explain the low-lying spectra and

^{110}Cd normal states.

2022, 46(7): 074102. doi: 10.1088/1674-1137/ac5d29

**Abstract:**

Excited states in low-energy spectra of

2022, 46(7): 074103. doi: 10.1088/1674-1137/ac5db8

**Abstract:**

Understanding the gluonic structure in nuclei is one of the most important goals in modern nuclear physics, for which

*J*/

*ψ*photoproduction is suggested as a powerful tool to probe the gluon density distribution. The experimental investigation of the photoproduction process is conventionally studied in ultra-peripheral heavy-ion collisions, and has recently been extended to hadronic collisions. However, theoretical efforts in hadronic heavy-ion collisions are still lacking in the literature. In this paper, we build up a phenomenological framework to calculate the differential momentum transfer spectra for

*J*/

*ψ*photoproduction in hadronic heavy-ion collisions based on a vector meson dominance model. For the first time, we include the effect of internal photon radiation in the calculations, and we find that the results with internal photon radiation could describe the experimental measurements from STAR very well.

2022, 46(7): 074104. doi: 10.1088/1674-1137/ac5efb

**Abstract:**

Machine learning models are constructed to predict fragment production cross sections in projectile fragmentation (PF) reactions using Bayesian neural network (BNN) techniques. The massive learning for BNN models is based on 6393 fragments from 53 measured projectile fragmentation reactions. A direct BNN model and physical guiding BNN via FRACS parametrization (BNN + FRACS) model have been constructed to predict the fragment cross section in projectile fragmentation reactions. It is verified that the BNN and BNN + FRACS models can reproduce a wide range of fragment productions in PF reactions with incident energies from 40 MeV/u to 1 GeV/u, reaction systems with projectile nuclei from

^{40}Ar to

^{208}Pb, and various target nuclei. The high precision of the BNN and BNN + FRACS models makes them applicable for the low production rate of extremely rare isotopes in future PF reactions with large projectile nucleus asymmetry in the new generation of radioactive nuclear beam factories.

2022, 46(7): 074105. doi: 10.1088/1674-1137/ac6154

**Abstract:**

The kernel ridge regression (KRR) method with a Gaussian kernel is used to improve the description of the nuclear charge radius by several phenomenological formulae. The widely used

2022, 46(7): 074106. doi: 10.1088/1674-1137/ac6153

**Abstract:**

In this study, shape evolution and possible shape coexistence are explored in odd-

*A*Ne isotopes in the framework of the multidimensionally constrained relativistic-mean-field (MDC-RMF) model. By introducing

^{31}Ne are found. In terms of the impurity effects of Λ hyperons, as noted for even-even Ne hypernuclear isotopes, the

2022, 46(7): 074107. doi: 10.1088/1674-1137/ac6248

**Abstract:**

The chirality in thallium isotopes is investigated using the adiabatic and configuration-fixed constrained triaxial relativistic mean field theory. Several minima with prominent triaxial deformation and proper configuration, where the chiral doublet bands may appear, are obtained in odd-odd nuclei

*χ*D) is demonstrated in

*χ*D in

^{195}Tl have been observed experimentally, further experimental exploration for the chirality in

*χ*D in thallium isotopes is expected to verify the predictions.

2022, 46(7): 074108. doi: 10.1088/1674-1137/ac6249

**Abstract:**

The spallation of

^{238}U is an important way to produce rare isotopes. This work aims at studying the cross sections of isotopes produced in

^{238}U +

*p*,

*d*and

^{9}Be reactions at 1

*A*GeV and their target dependence. (1) A physical model dependent (Bayesian neural network) BNN, which includes the details of IQMD-GEMINI++ model and BNN, was developed for a more accurate evaluation of production cross sections. The isospin-dependent quantum molecular dynamics (IQMD) model is used to study the non-equilibrium thermalization of the

^{238}U nuclei and fragmentation of the hot system. The subsequent decay of the pre-fragments is simulated by the GEMINI++ model. The BNN algorithm is used to improve the prediction accuracy after learning the residual error between experimental data and calculations by the IQMD-GEMINI++ model. It is shown that the IQMD-GEMINI++ model can reproduce the available experimental data (3282 points) within 1.5 orders of magnitude. After being fine tuned by the BNN algorithm, the deviation between calculations and experimental data were reduced to within 0.4 order of magnitude. (2) Based on the predictions by the IQMD-GEMINI++-BNN framework, the target dependence of isotopic cross sections was studied. The cross sections to produce the rare isotopes by the

^{238}U +

*p*,

*d*and

^{9}Be reactions at 1

*A*GeV are compared. For the generation of neutron-rich fission products, the cross sections for the

^{238}U +

^{9}Be are the largest. For the generation of neutron-deficient nuclei in the region of

*A*= 200–220, the cross sections for

^{238}U +

*p*reaction are the largest. Considering the largest cross sections and the atomic density, the beryllium target is recommended to produce the neutron-rich fission products by the

^{238}U beam at 1

*A*GeV, while the liquid-hydrogen target is suggested to produce the neutron-deficient nuclei in the region of

*A*

2022, 46(7): 074109. doi: 10.1088/1674-1137/ac6357

**Abstract:**

We present the hypernuclear states of

*s*-,

*p*-, or

*sd*-shell orbitals are discussed. For the

*s*-shell

*s*

*s*

*p*-shell

*sd*-shell

2022, 46(7): 074110. doi: 10.1088/1674-1137/ac6490

**Abstract:**

In this study, Au+Au collisions with an impact parameter of

2022, 46(7): 075101. doi: 10.1088/1674-1137/ac5d2a

**Abstract:**

We investigate the gravitational wave spectrum originating from the cosmological first-order phase transition. We compare two models: one is a scalar field model without gravitation, while the other is a scalar field model with gravitation. Based on the sensitivity curves of the LISA space-based interferometer on the stochastic gravitational-wave background, we compare the difference between the gravitational wave spectra of the former and the latter cases obtained from the bubble collision process. In particular, we numerically calculate the speed of the bubble wall before collision for the two models. We demonstrate that the difference between the amplitudes of these spectra can clearly distinguish between the two models. We expect that the LISA with Signal to Noise Ratio = 10 could observe the spectrum as the fast first-order phase transition.

2022, 46(7): 075102. doi: 10.1088/1674-1137/ac5e92

**Abstract:**

The application of fast radio bursts (FRBs) as probes for investigating astrophysics and cosmology requires proper modelling of the dispersion measures of the Milky Way (

2022, 46(7): 075103. doi: 10.1088/1674-1137/ac624a

**Abstract:**

The shadow and observation intensity of a black hole surrounded by a thin spherical accretion in the Randall–Sundrum brane world model are investigated. The bulk metric depends on the tidal charge parameter,

*q*, and deformation parameter,

*C*. It reduces to the metric that possesses similar form with the Reissner–Nordström metric if

*q*. The observation intensity is mainly influenced by the tidal charge parameter,

*q*, and the deformation parameter,

*C*, is of secondary importance. In the optical observation, the black holes appear brighter with higher

*q*or lower

*C*.

2022, 46(7): 079001. doi: 10.1088/1674-1137/ac5e26

**Abstract:**

Experimentally measured neutron activation cross sections are presented for the

*n*,

*α*)

*n*,

*α*)

*n,2n*)

*t*(

*d*,

*n*)

*α*fusion reaction. The

*n*,

*α*)

*γ*-ray spectra. The data from the measured cross sections are compared to the previously measured cross sections from the EXFOR database, theoretically calculated cross sections using the TALYS and EMPIRE codes, and evaluated nuclear data.

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

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

- Particle physics
- Nuclear physics
- Particle and nuclear astrophysics
- Cosmology

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