Chinese Physics C

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Scissors vibration and its collective rotation in a microscopic investigation
Fang-Qi Chen

2024, 48(12): 124101. doi: 10.1088/1674-1137/ad6e61

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The intrinsic vibrational motion and the rotational behavior of the scissors mode in well deformed nuclei are investigated with an angular-momentum-projected approach, which is interpreted as a generator-coordinate-method with the generator coordinates corresponding to the degrees of freedom of interest. The picture of the intrinsic and rotational motion of the scissors mode is illustrated from the collective wave function within the framework of the generator-coordinate-method. The harmonicity of the scissors vibration is found to arise naturally from the present model but can be disturbed by the Coriolis effect as spin increases. The odd and even spin members of the rotational band based on the scissors mode rotate about different axes perpendicular to each other, leading to the flipping moment of inertia and the consequent splitting behavior that has been suggested previously.
Operators of quantum theory of Dirac's free field
Ion I. Cotăescu

2024, 48(12): 123106. doi: 10.1088/1674-1137/ad745c

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The Pryce (e) spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations [Eur. Phys. J. C 82, 1073 (2022)]. This approach is generalized here, associating a pair of integral operators acting directly on particle and antiparticle wave spinors in momentum representation to any integral operator in configuration representation, acting on mode spinors. This framework allows an effective quantization procedure, giving a large set of one-particle operators with physical meaning as the spin and orbital parts of the isometry generators, the Pauli-Lubanski and position operators, or other spin-type operators proposed to date. Special attention is paid to the operators that mix the particle and antiparticle sectors whose off-diagonal associated operators have oscillating terms producing Zitterbevegung. The principal operators of this type, including the usual coordinate operator, are derived here for the first time. As an application, it is shown that an apparatus measuring these new observables may prepare and detect one-particle wave packets moving uniformly without Zitterbewegung or spin dynamics, spreading in time normally as any other relativistic or even non-relativistic wave packet.
Beauty-charm meson family with coupled channel effects and their strong decays
Wei Hao, Ruilin Zhu

2024, 48(12): 123101. doi: 10.1088/1674-1137/ad75f5

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We systematically examined the mass spectra and their two-body hadronic decays of the beauty-charm meson family considering coupled channel effects. Our results can effectively explain the observed $B_c$ meson spectrum, and the prediction of the mass spectrum for unobserved beauty-charm mesons can be tested in future experiments. Compared with previous studies, we systematically examine the beauty-charm meson family within the coupled channel components. The $1S$ state in beauty-charm meson family has few percent of coupled channel component, while the $2S$, $1P$, and $1D$ states have more than ten percent of coupled channel component. The two-body hadronic decay widths of the $2^3P_2$ state is as narrow as 3 MeV. The two-body hadronic decay widths of $3^1S_0$, $3^3S_1$, $2^3D_1$, $2D$, $2D^\prime$, and $2^3D_3$ are approximately 109, 67, 60, 57, 201, and 76 MeV, respectively. Furthermore, the mixing effects between $B_c(n{}^3L_L)$ and $B_c(n{}^1L_L)$ states are discussed.

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Improved constraints on Higgs boson self-couplings with quartic and cubic power dependencies in the cross section
Hai Tao Li, Zong-Guo Si, Jian Wang, Xiao Zhang, Dan Zhao

Published: 2024-12-21

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Published: 2024-12-21

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Quantifying the memory and dynamical stability of magnetar bursts
Yu Sang, Hai-Nan Lin

Published: 2024-12-21

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Published: 2024-12-21

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Simulation of dark scalar particle sensitivity in η rare decay channels at HIAF
Yang Liu, Rong Wang, Zaiba Mushtaq, Ye Tian, Xionghong He, Hao Qiu, Xurong Chen

Published: 2024-12-21

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Published: 2024-12-21

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Fixing three dimensional geometries from entanglement entropies of CFT₂
Peng Wang, Houwen Wu, Haitang Yang

2025, 49(2): 025106-025106-11. doi: 10.1088/1674-1137/ad93b8

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In this paper, we propose a method of fixing the leading behaviors of three dimensional geometries from the dual CFT₂ entanglement entropies. We employ only the holographic principle and do not use any assumption about the AdS/CFT correspondence and bulk geometry. Our strategy involves using both UV and IR-like CFT₂ entanglement entropies to fix the bulk geodesics. With a simple trick, the metric can be extracted from the geodesics. As examples, we fix the leading behaviors of the pure AdS₃ metric from the entanglement entropies of free CFT₂ and, more importantly, the BTZ black hole from the entanglement entropies of finite temperature CFT₂. Consequently, CFT₂ with finite size or topological defects can be determined through simple transformations. Following the same steps, in principle, the leading behaviors of all three dimensional (topologically distinct) holographic classical geometries from the dual CFT₂ entanglement entropies can be fixed.

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Spectroscopy of excited quarkonium states in the light-front quark model
Ritwik Acharyya, Satyajit Puhan, Harleen Dahiya, Narinder Kumar

2025, 49(2): 023104-023104-14. doi: 10.1088/1674-1137/ad8ec3

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We investigated the ground state (1S), radially excited states (2S) and (3S), and orbitally excited state (1P) for the heavy charmonia ($ c \bar c $) and bottomonia ($ b \bar b $) mesons in the light-front quark model (LFQM). The light-front wave functions have been successful in explaining various physical properties of meson states in the past, especially for the 1S and 2S states. However, the radially excited state 3S and orbitally excited state 1P have rarely been investigated. In this study, we considered these two excited states and investigated the electromagnetic form factors (EMFFs), charge radii, decay constants, parton distribution functions (PDFs), and the distribution amplitudes (DAs) for the quarkonia system. For the sake of completeness, we also studied the ground and the first excited states of quarkonia mesons. We also illustrated the 3D wave functions for the radially excited states to study their nodal structures.

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Primordial black holes and scalar induced density perturbations: the effects of probability density functions
Jing-Zhi Zhou, Yu-Ting Kuang, Zhe Chang, Xukun Zhang, Qing-Hua Zhu

2025, 49(2): 025105-025105-7. doi: 10.1088/1674-1137/ad972c

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We investigate the second order energy density perturbation $ \delta^{(2)} $ induced by small-scale Gaussian and local-type non-Gaussian primordial curvature perturbations. The relative abundance of primordial black holes (PBHs) is calculated in terms of the probability density functions (PDFs) of the total energy density perturbation $ \delta_r=\delta^{(1)}+\frac{1}{2}\delta^{(2)} $. The effects of the second order density perturbation greatly reduce the upper bounds of small-scale power spectra of primordial curvature perturbations by one to two orders of magnitude. For a log-normal primordial power spectrum, its amplitude $ A_{\zeta} $ is constrained to be approximately $ A_{\zeta}\sim 3\times10^{-3} $, and for the local-type non-Gaussianity with $ f_{\mathrm{NL}}=10 $, the upper bound of $ A_{\zeta} $ is approximately $ 2.5\times10^{-4} $.

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Current Issued

2024 Vol. 48, No. 12
Published: 02 December 2024

Particles And Fields
Nuclear Physics
Particle And Nuclear Astrophysics And Cosmology