Chinese Physics C

Highlights

Stable circular orbits and greybody factor of Hayward-Letelier-AdS black holes
Allah Ditta, Sulaman Shaukat, Faisal Javed, Abdelmalek Bouzenada, G. Mustafa, Bander Almutairi

2025, 49(11): 115104. doi: 10.1088/1674-1137/ade4a7

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This paper explores the dynamical feature of Hayward-Letelier black holes in AdS spacetime, emphasizing the effects of the Hayward parameter g, mass M, cosmological constant L, and modification parameter α on their geometry, thermodynamics, and observational features. By utilizing an effective potential method, we investigate the paths of particles, innermost stable circular orbit, and behavior of photon spheres, which connects them to the appearance of black hole shadows. Thermodynamic features such as Hawking temperature and entropy are studied for investigating the effect of L and thermal fluctuations on the stability of black holes. These discoveries connect theoretical ideas with observational astrophysics, which enhances our comprehension of ordinary black holes in AdS models. In this study, we analytically compute the greybody factor for a massless scalar field propagating in the vicinity of a black hole under the assumption of weak coupling to gravity. We investigate the behavior of the effective potential concerning the black hole's mass and charge, revealing that it reaches its maximum at lower values of the cloud of strings parameter. Our results indicate that the radial absorption rate of the scalar field exhibits significant fluctuations, which is influenced by the charge of the black hole and clouds of string, with implications for the dynamics of scalar fields in strong gravitational fields.
Sensitivity study of the tau lepton electric dipole moment at the Super Tau-Charm Facility
Xulei Sun, Yongcheng Wu, Xiaorong Zhou

2025, 49(11): 113001. doi: 10.1088/1674-1137/adf6e0

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This study investigates the intrinsic electric dipole moment (EDM) of the τ lepton, which is an important quantity in the search for physics beyond the Standard Model (BSM). In preparation for future measurements at the Super Tau-Charm Facility (STCF), we employ Monte Carlo simulations of the $ e^+e^- \rightarrow \tau^+\tau^- $ process and optimize the analysis methodology for EDM extraction. Machine learning techniques are implemented to efficiently identify signal events ($ \tau^\pm\rightarrow \pi^\pm\pi^0\nu_\tau $), which result in a significant improvement in signal-to-noise ratio. Our optimized event selection algorithm achieves 80.0% signal purity with 6.3% efficiency. We develop an analytical approach for τ lepton momentum reconstruction and derive the squared spin density matrix along with optimal observables, which maximize the sensitivity to $ d_\tau $. The relationship between these observables and the EDM is established with the estimated sensitivity of $ |d_\tau| < 3.89\times 10^{-18}\,e\cdot\mathrm{cm} $ at a 68% confidence level. These results provide a foundation for future experimental measurements of the τ lepton EDM in STCF experiments.
Measurement of separate electron and positron spectra from 10 to 20 GeV with the geomagnetic field on DAMPE
F. Alemanno, Q. An, P. Azzarello, F. C. T. Barbato, P. Bernardini, X. J. Bi, H. V. Boutin, I. Cagnoli, M. S. Cai, E. Casilli, E. Catanzani, J. Chang, D. Y. Chen, J. L. Chen, Z. F. Chen, Z. X. Chen, P. Coppin, M. Y. Cui, T. S. Cui, Y. X. Cui, I. De Mitri, F. de Palma, A. Di Giovanni, T. K. Dong, Z. X. Dong, G. Donvito, J. L. Duan, K. K. Duan, R. R. Fan, Y. Z. Fan, F. Fang, K. Fang, C. Q. Feng, L. Feng, J. M. Frieden, P. Fusco, M. Gao, F. Gargano, E. Ghose, K. Gong, Y. Z. Gong, D. Y. Guo, J. H. Guo, S. X. Han, Y. M. Hu, G. S. Huang, X. Y. Huang, Y. Y. Huang, M. Ionica, L. Y. Jiang, Y. Z. Jiang, W. Jiang, J. Kong, A. Kotenko, D. Kyratzis, S. J. Lei, M. B. Li, W. H. Li, W. L. Li, X. Li, X. Q. Li, Y. M. Liang, C. M. Liu, H. Liu, J. Liu, S. B. Liu, Y. Liu, F. Loparco, C. N. Luo, M. Ma, P. X. Ma, T. Ma, X. Y. Ma, G. Marsella, M. N. Mazziotta, D. Mo, Y. Nie, X. Y. Niu, A. Parenti, W. X. Peng, X. Y. Peng, C. Perrina, E. Putti-Garcia, R. Qiao, J. N. Rao, Y. Rong, R. Sarkar, P. Savina, A. Serpolla, Z. Shangguan, W. H. S

2025, 49(11): 115001. doi: 10.1088/1674-1137/adfa04

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The cosmic-ray (CR) electrons and positrons in space are of considerable significance for studying the origin and propagation of CRs. The satellite-borne detector Dark Matter Particle Explorer (DAMPE) has been used to measure the separate electron and positron spectra, as well as the positron fraction. In this study, the Earth's magnetic field is used to distinguish CR electrons and positrons, as the DAMPE detector does not carry an onboard magnet. The energy for the measurements ranges from 10 to 20 GeV, which is currently limited at high energy by the zenith-pointing orientation of DAMPE. The results are consistent with previous measurements based on the magnetic spectrometer by AMS-02 and PAMELA, whereas the results of Fermi-LAT appear to be systematically shifted to larger values.

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The properties of the S-wave D_sD_s bound state
Jing-Juan Qi, Zhen-Yang Wang, Zhu-Feng Zhang, Xin-Heng Guo

Published: 2025-11-02, doi: 10.1088/1674-1137/ae1195

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Published: 2025-11-02, doi: 10.1088/1674-1137/ae1195

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0νββ decay nuclear matrix elements under Left-Right symmetric model from the spherical quasi-particle random phase approximation method with realistic force
Ri-Guang Huang, You-Cai Chen, Dong-Liang Fang

Published: 2025-11-02

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Published: 2025-11-02

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Neutron stars and Pulsar timing arrays as Axion giant gyroscopes
Jinneng Luo, Yiming Liu, Sichun Sun

Published: 2025-11-02, doi: 10.1088/1674-1137/ae1189

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Published: 2025-11-02, doi: 10.1088/1674-1137/ae1189

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Hawking tunneling radiation with thermodynamic pressure
Cheng Hu, Xiao-Xiong Zeng

2026, 50(1): 015103-015103-8. doi: 10.1088/1674-1137/ae07b4

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Hawking radiation elucidates black holes as quantum thermodynamic systems, thereby establishing a conceptual bridge between general relativity and quantum mechanics through particle emission phenomena. While conventional theoretical frameworks predominantly focus on classical spacetime configurations, recent advancements in extended phase space thermodynamics have redefined cosmological parameters (such as the Λ-term) as dynamic variables. Notably, the thermodynamics of anti-de Sitter (AdS) black holes has been successfully extended to incorporate thermodynamic pressure P. Within this extended phase space framework, although numerous intriguing physical phenomena have been identified, the tunneling mechanism of particles incorporating pressure and volume remains unexplored. This study investigates Hawking radiation through particle tunneling in Schwarzschild AdS black holes within the extended phase space, where the thermodynamic pressure P is introduced via a dynamic cosmological constant Λ. By employing semi-classical tunneling calculations with self-gravitation corrections, we demonstrate that emission probabilities exhibit a direct correlation with variations in Bekenstein-Hawking entropy. Significantly, the radiation spectrum deviates from pure thermality, aligning with unitary quantum evolution while maintaining consistency with standard phase space results. Moreover, through thermodynamic analysis, we verified that the emission rate of particles is related to the difference in Bekenstein-Hawking entropy of the emitted particles before and after they tunnel through the potential barrier. These findings establish particle tunneling as a unified probe of quantum gravitational effects in black hole thermodynamics.

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Valence quark distributions of pions: insights from Tsallis entropy
Jingxuan Chen, Xiaopeng Wang, Yanbing Cai, Xurong Chen, Qian Wang

2026, 50(1): 013103-013103-6. doi: 10.1088/1674-1137/ae0998

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We investigate the valence quark distributions of pions at a low initial scale ($Q^2_0$) using Tsallis entropy, a non-extensive measure that effectively captures long-range correlations among internal constituents. Utilizing the maximum entropy approach, we adopt two distinct functional forms and fit experimental data using the elegant GLR-MQ-ZRS evolution equation to derive the model parameters. Our findings indicate that the resulting valence quark distributions provide an optimal fit to the experimental data, with q values deviating from unity. This deviation indicates that correlations among valence quarks play a significant role in shaping understanding of the internal structures of pions. Additionally, our computations of the first three moments of the pion quark distributions at $ Q^2 = 4$ GeV² display consistency with other theoretical models, thereby reinforcing the importance of incorporating valence quark correlations within this analytical framework.

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Development of cesium laser resonance ionization schemes for PLASEN experiment
Yangfan Guo, Zhou Yan, Xiaofei Yang, Shaojie Chen, Wencong Mei, Hanrui Hu, Yinshen Liu, Dongyang Chen, Chen Zhang, Tianxu Gao, Yipin Jing, Yanlin Ye

2025, 49(12): 124002-124002-6. doi: 10.1088/1674-1137/adf49e

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To study the nuclear properties and deformation of neutron-rich cesium isotopes in their ground and isomeric states at the Beijing Rare Isotope Beam Facility (BRIF), optimal resonance ionization schemes and experimental conditions must be predetermined. In this study, we evaluated several three-step laser resonance ionization schemes for cesium atoms by accessing their ionization efficiency and spectral resolution under varying measurement conditions using high-resolution and high-sensitivity collinear resonance ionization spectroscopy system. Hence, we identified the currently most efficient resonance ionization scheme and optimal experimental conditions, achieving an overall measurement efficiency of 1: 400 with a spectral resolution of about 100 MHz. Under this condition, the extracted hyperfine structure parameters of ¹³³Cs showed excellent agreement with previously reported values. This study establishes a solid foundation for the forthcoming online measurement of neutron-rich cesium isotopes at BRIF.

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Current Issued

2025 Vol. 49, No. 11
Published: 01 October 2025

Particles And Fields
Nuclear Physics
Particle And Nuclear Astrophysics And Cosmology