Chinese Physics C

Highlights

CP violations and branching ratios for B_c⁺→ D_(s)⁺π⁺π⁻(K⁺K⁻) from interference of the vector mesons in Perturbative QCD
Kun Shuai Ye, Gang Lü, Na Wang, Jian Chai, Xin-Heng Guo

2025, 49(9): 093108. doi: 10.1088/1674-1137/add523

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Within the framework of the perturbative QCD approach utilizing $k_T$ factorization, we investigated the CP violation and branching ratios in the decay processes of $B_{c}^{+}\to D_{(s)} ^{+}V(V\rightarrow\pi^{+}\pi^{-})$ and $B_{c}^{+}\to D_{(s)}^{+}V(V\rightarrow K^{+}K^{-})$, where V denotes the three vector mesons $\rho^0$, ω, and ϕ. During the $V\to \pi^+\pi^-$ and $V\to K^+K^-$ decay processes, we incorporated the $\rho^{0}-\omega-\phi$ mixing mechanism to describe the amplitudes of these quasi-two-body decays. Within the interference region of the three vector particles, we observed distinct changes in both CP violations and branching ratios. Furthermore, our study presents evidence for local CP violations and branching ratios that warrants further experimental investigation.
Predictions of unknown masses using a feedforward neural network
Cheng-wei Dai, Hui Jiang, Yang Lei

2025, 49(9): 094111. doi: 10.1088/1674-1137/add10a

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In this study, a feedforward neural network (FNN) approach is employed to optimize three local mass models (GK, GKs, and GK+J). We find that adding physical quantities related to the pairing effect in the input layer can effectively improve the prediction accuracy of local models. For the known masses in AME2012, the FNN reduces the root-mean-square deviation between theory and experiment for the three mass models by 11 keV, 32 keV, and 623 keV. Among them, the improvement effect of the light mass region with mass number between 16 and 60 is better than that of medium and heavy mass regions. The approach also has good optimization results when extrapolating AME2012 to AME2020 and the latest measured masses after AME2020. Based on the improved mass data, the separation energies for single- and two-proton (neutron) emissions and α-decay energies are obtained, which agree well with the experiment.
A three-body form factor at sub-leading power in the high-energy limit: planar contributions
Yishuai Guo, Zhi-Feng Liu, Mingming Lu, Tianya Xia, Li-Lin Yang

2025, 49(9): 093102. doi: 10.1088/1674-1137/addcc7

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We analyzed two-loop planar contributions to a three-body form factor at next-to-leading power in the high-energy limit, where the masses of the external particles are much smaller than their energies. Calculations were performed by exploiting differential equations for the expansion coefficients, both to facilitate linear relations among them and to derive their analytic expressions. The results are expressed in terms of generalized polylogarithms involving a few simple symbol letters. Our method can readily be applied to calculations of non-planar contributions as well. Our results provide crucial information for establishing sub-leading factorization theorems for massive scattering amplitudes in the high-energy limit.

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Anisotropic quark propagation and Zeeman effect in an external magnetic field
Minghui Ding, Fei Gao, Sebastian M. Schmidt

Published: 2025-09-29

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Published: 2025-09-29

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³H and ³He nuclei production in a combined thermal and coalescence framework for heavy-ion collisions in the few-GeV energy regime
Zbigniew Drogosz, Wojciech Florkowski, Nikodem Witkowski, Radoslaw Ryblewski

Published: 2025-09-29

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Published: 2025-09-29

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Extracting the kinetic freeze-out properties of high energy pp collisions at the LHC with event shape classifiers
Jialin He, Xinye Peng, Zhongbao Yin, Liang Zheng

Published: 2025-09-28

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Published: 2025-09-28

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Investigation of cluster states around ²⁰Ne including spin-orbit coupling and its extension to heavier nuclei
Tao Wan, Shu-Lin Tang, Yi-Bin Qian

2025, 49(12): 124103-124103-10. doi: 10.1088/1674-1137/adf317

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Clustering, as a fundamental dynamical feature existing widely in many-body systems, has aroused tremendous interest in nuclear physics over the last few decades. The α-cluster concept has been used successfully to describe the energy spectra and electromagnetic transitions for a series of nuclei above the doubly magic core. In the present study, we have systematically investigated the spectroscopic properties of three-nucleon and α-cluster states in ¹⁹F and ²¹Ne within the binary cluster-core model (BCM) plus the extra spin-orbit potential. The calculated energy levels and electromagnetic transition strengths, with few exceptions, are in good agreement with experimental data, confirming the reliability and integrity of BCM. Furthermore, such a BCM is extended to the case of cluster states approaching shell closures in heavier nuclei, such as ⁴³Sc, ⁵⁹Cu, and ⁹³Mo, leading to satisfactory reproductions and predictions on energy levels and reduced transition rates. It is expected that the present study can provide further insight into the cluster degrees of freedom in odd-A nuclei.

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Theoretical study of Strong gravitational lensing around Dyonic ModMax black hole: constraints from EHT observations
Lola Meliyeva, Obid Xoldorov, Olmos Tursunboyev, Shavkat Karshiboev, Sardor Murodov, Isomiddin Nishonov, Bekzod Rahmatov

2025, 49(12): 125102-125102-10. doi: 10.1088/1674-1137/adf4a0

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In this study, we investigate the properties of the Dyonic ModMax black hole solution using strong gravitational lensing. Additionally, we calculate the time delay between two relativistic images of a background object. First, we analyze expressions for the photon orbits in the spacetime of the Dyonic ModMax black hole. To obtain observational consequences, we provide expressions for the observable quantities, such as angular radius and magnifications. The numerous observations suggest that many nearby galaxies contain supermassive central black holes. In our model, such a supermassive black hole can be characterized by two additional parameters: γ and Q. Notably, the bending angle $ \alpha_D(b) $ and the angular position $ \theta_\infty $ decrease with increasing charge of the black hole Q, while the parameter γ displays opposite behavior to that of Q. By using observational data of supermassive black holes $ \mathrm{SgrA}^* $ and $ \mathrm{M}87^* $, we obtain constraints for these parameters.

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Refinement of an analytical capture cross section formula
Ning Wang

2025, 49(12): 124106-124106-8. doi: 10.1088/1674-1137/adfe53

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An analytical formula with high accuracy is proposed for a systematic description of the capture cross sections at near-barrier energies from light to superheavy reaction systems. Based on the empirical barrier distribution method, three key input quantities are refined by introducing nuclear surface correction to the Coulomb parameter z for calculating the barrier height, incorporating the reaction Q-value and shell correction into the barrier distribution width calculations, and considering the deep inelastic scattering effects of superheavy systems on the barrier radius. With these refinements, the accuracy of not only the calculated barrier height but also the predicted capture cross sections is substantially improved. The average deviation (in logarithmic scale) between the predicted cross sections and the experimental data for 426 reaction systems with $ 35 < Z_1 Z_2 < 2600 $ is sharply reduced from 3.485 to 0.113.

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Current Issued

2025 Vol. 49, No. 10
Published: 25 September 2025

Particles And Fields
Nuclear Physics
Particle And Nuclear Astrophysics And Cosmology