Highlights
• Spectroscopic investigation of light strange S = −1 Λ and Σ and S = −2 Ξ baryons
2021, 45(6): 063108. doi: 10.1088/1674-1137/abf4f4
The present study is dedicated to light-strange $\Lambda$ with strangeness S = −1 and isospin I = 0, $\Sigma$ with S = −1 and I = 1, and $\Xi$ baryon with S = −2 and $I=\dfrac{1}{2}$. In this study, the hypercentral constituent quark model with linear confining potential has been employed along with a first order correction term to obtain the resonance masses up to approximately 4 GeV. The calculated states include 1S-5S, 1P-4P, 1D-3D, 1F-2F, and 1G (in a few cases) along with all possible spin-parity assignments. Regge trajectories have been explored for the linearity of the calculated masses for $(n,M^{2})$ and $(J,M^{2})$. Magnetic moments have been intensively studied for ground state spin $\dfrac{1}{2}$ and $\dfrac{3}{2}$, in addition to the configuration mixing of the first negative parity state for $\Xi$. Lastly, the transition magnetic moments and radiative decay widths have been presented.
• Pair production in Reissner-Nordström-Anti de Sitter black holes
2021, 45(6): 065105. doi: 10.1088/1674-1137/abf4f6
We studied the pair production of charged scalar particles of a five-dimensional near extremal Reissner-Nordström-Anti de Sitter (RN-AdS5) black hole. The pair production rate and the absorption cross section ratio in full spacetime are obtained and are shown to have a concise relation with their counterparts in the near horizon region. In addition, the holographic descriptions of the pair production, both in the IR CFT in the near horizon region and the UV CFT at the asymptotic spatial boundary of the RN-AdS5 black hole, are analyzed in the AdS2/CFT1 and AdS5/CFT4 correspondences, respectively. This work gives a complete description of scalar pair production in a near extremal RN-AdS5 black hole.
• Initial years’ neutron-induced cross-section measurements at the CSNS Back-n white neutron source
2021, 45(6): 062001. doi: 10.1088/1674-1137/abf138
The Back-n white neutron source (known as Back-n) is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source (CSNS). With its excellent beam properties, e.g., a neutron flux of approximately 1.8×107 n/cm2/s at 55 m from the spallation target, energy range spanning from 0.5 eV to 200 MeV, and time-of-flight resolution of a few per thousand, along with the equipped physical spectrometers, Back-n is considered to be among the best facilities in the world for carrying out nuclear data measurements. Since its completion and commencement of operation in May 2018, five types of cross-section measurements concerning neutron capture cross-sections, fission cross-sections, total cross-sections, light charged particle emissions, in-beam gamma spectra, and more than forty nuclides have been measured. This article presents an overview of the experimental setup and result analysis on the neutron-induced cross-section measurements and gamma spectroscopy at Back-n in the initial years.
In Press
More >
• Effects of an odd particle on shape phase transitions in odd-even systems
Published: 2021-06-22, doi: 10.1088/1674-1137/ac05a0
Show Abstract
A scheme to solve the Hamiltonian in the interacting boson-fermion model in terms of the SU(3) coupling basis is introduced, through which the effects of an odd particle on shape phase transitions (SPTs) in odd-A nuclei are examined by comparing the critical behaviors of some selected quantities in odd-even and even-even systems. The results indicate that the spherical to prolate (U(5)-SU(3)) SPT and spherical to $\gamma$-soft (U(5)-O(6)) SPT may clearly occur in the odd-even system with the SPT signatures revealed by various quantities including the excitation energies, energy ratio, $B(E2)$ ratio, quadrupole moments, and one-particle-transfer spectroscopic intensities. In particular, the results indicate that the spherical to prolate SPT in the odd-even system can even be strengthened by the effects of the odd particle with the large fluctuations of the quadrupole deformations appearing near the critical point.
• Hawking radiation received at infinity in higher dimensional Reissner-Nordström black hole spacetimes
Published: 2021-06-22, doi: 10.1088/1674-1137/ac0419
Show Abstract
In this study, we investigate the Hawking radiation in higher dimensional Reissner-Nordström black holes as received by an observer located at infinity. The frequency-dependent transmission rates, which deform the thermal radiation emitted in the vicinity of the black hole horizon, are evaluated numerically. In addition to those in four-dimensional spacetime, the calculations are extended to higher dimensional Reissner-Nordström metrics, and the results are observed to be sensitive to the spacetime dimension to an extent. Generally, we observe that the transmission coefficient practically vanishes when the frequency of the emitted particle approaches zero. It increases with frequency and eventually saturates to a certain value. For four-dimensional spacetime, the above result is demonstrated to be mostly independent of the metric's parameter and the orbital quantum number of the particle, when the location of the event horizon, $r_h$, and the product of the charges of the black hole and the particle qQ are known. However, for higher-dimensional scenarios, the convergence becomes more gradual. Moreover, the difference between states with different orbital quantum numbers is observed to be more significant. As the magnitude of the product of charges qQ becomes more significant, the transmission coefficient exceeds 1. In other words, the resultant spectral flux is amplified, which results in an accelerated process of black hole evaporation. The relationship of the calculated outgoing transmission coefficient with existing results on the greybody factor is discussed.
• Chiral phase transition and equation of state in chiral imbalance
Published: 2021-06-18, doi: 10.1088/1674-1137/ac0329
Show Abstract
The chiral phase transition and equation of state are studied within a novel self-consistent mean-field approximation of the two-flavor Nambu-Jona-Lasinio model. In this newly developed model, modifications to the chemical μ and chiral chemical $\mu_5$ potentials are naturally included by introducing vector and axial-vector channels from Fierz-transformed Lagrangian to the standard Lagrangian. In the proper-time scheme, the chiral phase transition is a crossover in the $T-\mu$ plane. However, when $\mu_5$ is incorporated, our study demonstrates that a first order phase transition may emerge. Furthermore, the chiral imbalance will soften the equation of state of quark matter. The mass-radius relationship and tidal deformability of quark stars are calculated. The maximum mass and radius decrease as $\mu_5$ increases. Our study also indicates that the vector and axial-vector channels exhibit an opposite influence on the equation of state.
Current Issued
2021 Vol. 45, No. 7
Published:
Archive