Chinese Physics C

Highlights

Moments from momentum derivatives in lattice QCD
Zhuoyi Pang, Jian-Hui Zhang, Dian-Jun Zhao

2025, 49(10): 101001. doi: 10.1088/1674-1137/aded04

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We show that the traditional moments approach in lattice quantum chromodynamics based on operator product expansion can be realized such that it utilizes derivatives in momentum rather than in distance. This avoids power divergent mixings, and thus allows to extract moments order by order to all orders in principle. Further, by exploiting the symmetry of lattice matrix elements, we can determine the even and odd moments separately. As a demonstrative example, we determine the first three moments beyond the tensor charge $ g_T$ of the isovector quark transversity distribution in the nucleon.
Improvements of time-of-flight detector utilizing a thin foil and crossed static electric and magnetic fields
Tetsuaki Moriguchi, Momo Mukai, Naoto Kaname, Akira Ozawa, Shinji Suzuki, Yasushi Abe, Hiroki Arakawa, Tomoya Fujii, Daiki Hamakawa, Sakumi Harayama, Shun Hosoi, Yasuto Inada, Kumi Inomata, Reo Kagesawa, Daisuke Kajiki, Daiki Kamioka, Masanori Kanda, Atsushi Kitagawa, Takaaki Kobayashi, Daisuke Nagae, Sarah Naimi, Kunimitsu Nishimuro, Shunichiro Omika, Misaki Otsu, Mamoru Sakaue, Shinji Sato, Hibiki Seki, Naru Shinozaki, Takeshi Suzuki, Keisuke Tomita, Takayuki Yamaguchi, Yoshitaka Yamaguchi, Asahi Yano, Kenjiro Yokota

2025, 49(10): 104001. doi: 10.1088/1674-1137/ade95b

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We developed a time-of-flight (TOF) detector with a thin foil for mass measurements of unstable nuclei using the Rare-RI Ring at the RIKEN RI beam factory. Compared to the previous design, the developed TOF detector employed modified electrodes, and its static electric and magnetic fields were reduced. We improved the detection efficiency and stability of operation. Its specification and design were finally fixed for mass measurements. We also developed a position-sensitive detector based on the principles of the TOF detector. This study utilized larger microchannel plate (MCP) detectors than those of the prototype. By improving acceptance, we demonstrated the performance of the position-sensitive detector with very low material thickness.
Unveiling the electromagnetic structure and intrinsic dynamics of spin-3/2 hidden-charm pentaquarks: A comprehensive QCD analysis
Ulaş Özdem

2025, 49(10): 103106. doi: 10.1088/1674-1137/ade95a

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In this study, we investigate the electromagnetic properties $ - $ specifically, the magnetic dipole, electric quadrupole, and magnetic octupole moments $ - $ of six hidden-charm pentaquark states: $ [u u][d c] \bar c $, $ [dd][u c] \bar c $, $ [u u][s c] \bar c $, $ [dd] [s c] \bar c $, $ [s s][u c] \bar c $, and $ [s s][d c] \bar c $. Employing the framework of QCD light-cone sum rules and utilizing two distinct diquark-diquark-antiquark interpolating currents, we focus on pentaquark configurations with spin-parity quantum numbers $ \rm{\mathit{J}}^{\rm{\mathit{P}}}=3/2^- $. The numerical results demonstrate significant deviations between the magnetic dipole moments predicted using different diquark-diquark-antidiquark structures. These results suggest that multiple pentaquark states with identical quantum numbers and quark constituents may exhibit distinct magnetic dipole moments, depending on their internal quark configurations. The obtained electromagnetic moments, particularly the variations in magnetic dipole moments, may provide insights into the internal structure of hidden-charm pentaquark states.

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Interplay of 95 GeV Diphoton Excess and Dark Matter in Supersymmetric Triplet Model
Zetian Li, Ning Liu, Bin Zhu

Published: 2025-10-30

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Published: 2025-10-30

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Searching Quantum Entanglement in pp → ZZ process
Alim Ruzi, Youpeng Wu, Ran Ding, Qiang Li

Published: 2025-10-28

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Published: 2025-10-28

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Predictions for the isospin-violating decays of ${{\boldsymbol B}_{\boldsymbol c}({\boldsymbol{1P}})^{\bf +}\bf\to{\boldsymbol B}_{\boldsymbol c}^{({\bf *})+}\boldsymbol\pi^{\bf 0}}$
Jun Wang, Qiang Zhao

Published: 2025-10-28

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Published: 2025-10-28

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Improvement of nuclear semi-empirical mass formula by including shell effect
Qing Wu, Wei-Feng Li, Zhong-Ming Niu, Hao-Zhao Liang, Min Shi

2025, 49(11): 114103-114103-9. doi: 10.1088/1674-1137/ade954

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Shell effect plays an important role in nuclear mass predictions, especially for the nuclei around the magic numbers. In this study, a new semi-empirical shell correction term is constructed to improve the mass description of the Bethe-Weizsäcker (BW) formula. For nuclei with $ Z,~N \geqslant 8$, the root mean square (rms) deviation of the newly proposed formula with respect to the latest nuclear mass evaluation dataset AME2020 is 0.887 MeV, inducing a 72.23% reduction compared to the rms deviation of 3.194 MeV for the BW formula. The deviations between the theoretical predictions and experimental data are within 1.5 MeV for 91.90% of the nuclei. In addition, the new mass formula significantly improves the predictions of the binding energies for magic nuclei. The rms deviation of our formula for the binding energy of magic nuclei is only 1.065 MeV, which is a 80.08% reduction compared with that of the BW formula.

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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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Current Issued

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

Particles And Fields
Nuclear Physics
Particle And Nuclear Astrophysics And Cosmology