Chinese Physics C

Highlights

Spontaneous scalarization of regular Hayward black holes in Einstein-nonlinear electromagnetic-scalar gravity
Lan-Lan Cai, Meng-Yun Lai, De-Cheng Zou, Lina Zhang, Hyat Huang

2026, 50(9): 095104. doi: 10.1088/1674-1137/ae836d

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Regular Hayward black holes provide a useful setting for investigating scalarization in theories with nonminimally coupled matter sectors. Within the framework of Einstein-nonlinear electromagnetic-scalar gravity, we identify the tachyonic threshold that signals the bifurcation from the bald Hayward background and then obtain scalarized charged black holes for both quadratic $ (1-\alpha\phi^2) $ and exponential $ ({\rm e}^{-\alpha \phi^2}) $ couplings. These configurations form a discrete set of branches classified by the number of nodes in the scalar field. The branch with $ n=0 $ is the fundamental branch, whereas solutions with $ n\geq 1 $ are excited branches. By studying radial perturbations, we find that the fundamental branch is stable for both coupling choices, which makes it the most relevant branch for future phenomenological and observational studies.
LHC shines on positivity
Zhen Liu, Kun-Feng Lyu, Tong Arthur Wu

2026, 50(9): 091003. doi: 10.1088/1674-1137/ae74be

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We show that hadron colliders have an excellent reach for positivity tests on a class of diphoton operators. Due to the helicity selection rules, the relevant dimension-6 operators either do not contribute or are highly constrained by other experimental observables. We demonstrate, for the first time, that the LHC can probe the positivity of the dimension-8 operators involving colored particles. The kinematic differential distributions of the diphoton final states are utilized to perform the $ \chi^2$ analysis. Through a global fit, the effective scale for these operators can be inclusively probed up to around 2 TeV at HL-LHC and over 5 TeV at future 100 TeV FCC-hh at 95% C.L., providing a powerful test of the positivity bounds up to the multi-TeV scale.
Covariant canonical-spinor amplitudes for partial wave analysis
Hong Huang, Yi-Ning Wang, Jiang-Hao Yu

2026, 50(9): 093110. doi: 10.1088/1674-1137/ae6a86

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We propose a covariant orbital-spin (LS) decomposed amplitude for the partial wave analysis using the massive spinor-helicity formalism. First, we review the traditional-LS method in the little group space and the Zemach tensor method in the double cover of the $ S O(3) $ space. To recover the $S O(3,1)$ Lorentz covariance, several Lorentz covariant $LS$ tensors have been constructed through different methods: covariant tensor, covariant projection tensor in pure-spin and general-spin schemes. However, performing an intrinsic separation between $LS$ coupling while maintaining covariance is not straightforward. We utilize the massive canonical-spinor variables to determine general three-point amplitudes, where the $LS$ decomposition is realized in a single little group space by projecting little group indices of each particle into one, while ensuring Lorentz covariance by the spinor form naturally. This covariant spinor method allows direct evaluation in any frame and offers a streamlined treatment of cascade decays within a single frame without additional alignment rotations needed in non-covariant approaches. As a benchmark, we implement the method in TF-PWA and analyze $\Lambda_c^+\to\Lambda\pi^+\pi^0$, finding consistent fit results across the helicity, traditional-$LS$, and canonical-spinor amplitudes. This validates the canonical-spinor amplitude as a practical tool for modern partial wave analyses of complex decay chains.

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Constraints on the canonical single-field slow-roll inflation model from observations
Jun Li, Guanghai Guo, Pengfei Yan, Xiong Yang

Published: 2026-08-19, doi: 10.1088/1674-1137/ae8cf2

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Published: 2026-08-19, doi: 10.1088/1674-1137/ae8cf2

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The resonance effect for the CP asymmetry associated with the process ${\boldsymbol\omega{\bf\to}{\boldsymbol\pi}^+{\boldsymbol\pi}^-{\boldsymbol\pi}^{\bf 0} }$
Xi-Liang Yuan, Gang Lü, Na Wang, Chao Wang

Published: 2025-05-26, doi: 10.1088/1674-1137/ad8ec2

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Published: 2025-05-26, doi: 10.1088/1674-1137/ad8ec2

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Study of radiative proton capture by the ⁷Be nucleus with the use of ab initio approaches
D. M. Rodkin, Yu. M. Tchuvil'sky

2026, 50(11): 114102-114102-11. doi: 10.1088/1674-1137/ae836e

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A theoretical study of the ⁷Be(p, γ)⁸B reaction in the "astrophysical" energy range with the use of ab initio methods is presented. The used approaches are No-Core Shell Model and Cluster Channels Orthogonal Functions Method. The scheme also contains elements of R-matrix theory and procedures for extrapolating various data obtained in ab initio computations. The developed approach as a whole allows one not only to calculate the astrophysical S-factor and all nuclear characteristics that determine its value, but also to evaluate the reliability of the obtained results and to identify the dominant reaction mechanisms against a background of insignificant ones. The high accuracy of the obtained results and has been demonstrated.

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Observational constraints on fractional holographic dark energy in the light of DESI DR2
Qihong Huang, Yuchen Zhang, Bing Xu, Kaituo Zhang

2026, 50(11): 115104-115104-12. doi: 10.1088/1674-1137/ae9926

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Based on the fractional entropy from fractional quantum mechanics, fractional holographic dark energy (FHDE) has been proposed with the Hubble horizon as the IR cutoff (FHDEH). We extend this framework by adopting the future event horizon and the particle horizon as the IR cutoff and proposing the FHDEF and FHDEP models. Using the SN+OHD+DESI DR2 dataset to constrain these models, we find that all three models provide a marginally lower $\chi^{2}_{\min}$ compared to ΛCDM but without significant preference according to AIC and BIC. When CMB distance priors are included, the FHDEH and FHDEP models are strongly ruled out. We further analyze the cosmological evolution for these models, and find that only the FHDEF model predicts nearly identical evolutions of $ \Omega_{m} $ and $ \Omega_{\rm de} $ to those of the ΛCDM model across cosmic history, but its deceleration parameter q deviates from the ΛCDM model in the future, indicating richer late time dynamics beyond the standard ΛCDM cosmology.

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Charge-exchange reactions accompanied by a single π⁺ production in medium-energy heavy-ion collisions
Xiaolei Chen, Jinyu Yang, Shikang Dong, Baowei Ding, Bitao Hu, Xiyu Qiu

2026, 50(11): 114101-114101-12. doi: 10.1088/1674-1137/ae9050

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Heavy-ion charge-exchange (CE) reactions provide a sensitive probe of isospin dynamics in nuclear collisions. We investigate the reaction $^{12}\mathrm{C}(^{12}\mathrm{C},\,^{12}{\rm N}\,{\pi}^{+})\,^{12}\mathrm{Be}$ at 400−600 A MeV using the ultra-relativistic quantum molecular dynamics model coupled with a phase-space coalescence approach. This reaction constitutes a nontrivial CE channel accompanied by single ${\pi}^+$ production in heavy-ion collisions, thereby extending previous studies from lepton-induced to hadronic systems. The $^{12}{\rm N}$ fragment is formed via nucleon and meson exchange, while ${\pi}^+$ production is primarily governed by ∆ resonance excitation and decay; this dual mechanism enables the simultaneous investigation of CE processes and ∆-induced pion production within the same reaction system. We calculate the reaction cross section and analyze the four-momentum distributions of $^{12}{\rm N}$ and ${\pi}^+$. Characteristic phase-space features reflect these distinct production mechanisms and offer guidance for future experimental design. Furthermore, this reaction could serve as a pathway for rare-isotope production.

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Current Issued

2026 Vol. 50, No. 9
Published: 31 August 2026

Particles And Fields
Nuclear Physics
Particle And Nuclear Astrophysics And Cosmology