Chinese Physics C

Pseudopotential of Hybrid Mesons in a Holographic Anisotropic Plasma

Jing Zhou, Saiwen Zhang

Published: , doi: 10.1088/1674-1137/ae5a88

Abstract:
We investigate the pseudopotential of hybrid mesons in a holographic anisotropic background within the AdS/CFT correspondence. Hybrid states are modeled by introducing a defect, and we analyze the associated force-balance condition in the string configuration. From this setup, we derive the balance equation and compute key physical quantities, including the separation distance, pseudopotential, and binding energy of the hybrid mesons. We find that increasing the anisotropy parameter a decreases the separation distance for both ground and excited states. However, while the ground-state potential decreases, the pseudopotential of the hybrid state increases. Additionally, the pseudopotential of hybrid mesons exhibits significant sensitivity to variations in the angular parameter α.

ModMax charged black holes in PFDM: Electric Penrose and particle collisions

Nuriddin Kurbonov, Mukhabbat Kurbanova, Javlon Rayimbaev, Yunus Turaev, Sulton Usanov, Saidmuhammad Ahmedov

Published: , doi: 10.1088/1674-1137/ae5b56

Abstract:
In this study, we investigate the influence of the parameters of ModMax nonlinear electrodynamics and perfect-fluid dark matter (PFDM) on the geometry and physical properties of charged black holes. A static, spherically symmetric solution to the Einstein field equations describing a charged ModMax black hole immersed in a PFDM background is obtained. The motion of charged test particles in this spacetime is analyzed in detail, including the effective potential, the conditions for stable and unstable circular orbits, and the radius of the innermost stable circular orbit (ISCO). It is shown that the ModMax parameter γ shifts the orbits outward for repulsive Coulomb interactions and inward for attractive forces, while increasing PFDM enhances gravitational attraction, shifting the ISCO inward. Furthermore, the interactions and collisions of charged particles near the event horizon are examined. The center-of-mass energy

\begin{document}${\cal{E}}_{cm}$\end{document}

exhibits the characteristic behavior in charged-particle collisions, rapidly increasing as the particles approach the horizon. The parameter γ amplifies the BSW acceleration mechanism, while α suppresses it. The electric Penrose process for charged particles is also examined, revealing that the efficiency of energy extraction increases with the black hole charge and is strongly influenced by the interaction parameter γ, which plays a dominant role in enhancing the efficiency, whereas the effect of α remains comparatively negligible.

S, T, U Parameters in The B-LSSM

Sheng-Kai Cui, Ke-Sheng Sun, Yu-Li Yan, Jin-Lei Yang, Tai-Fu Feng

Published: , doi: 10.1088/1674-1137/ae5590

Abstract:
Using the pinch technique, we compute the one-loop vertices of weak interactions in the B-LSSM and incorporate their pinch contributions into the gauge boson self-energies. Compared to the definitions of the S, T, and U parameters in the Standard Model based on the

\begin{document}$SU(2)_L \otimes U(1)_Y$\end{document}

group, the corresponding parameters in the local B-L gauge symmetry (B-LSSM) are modified. We provide these redefined S, T, and U parameters and demonstrate the convergence of the results. In the framework of the low-energy effective Lagrangian for weak interactions, the S, T, and U parameters can be expressed as functions of certain parameters in the B-LSSM. The updated experimental and fitting results constrain the parameter space of the B-LSSM strongly.

Exploring muonphilic dark matter with the Z₂-even mediator at muon colliders

Wanyun Chen, Haoqi Li, Chih-Ting Lu, Qiulei Wang

Published: , doi: 10.1088/1674-1137/ae5044

Abstract:
The Galactic Center GeV Excess (GCE) remains a compelling but enigmatic signal from the inner region of our galaxy. Muonphilic dark matter (DM), which couples exclusively to muons via a new mediator, provides a viable explanation for the GCE and relic density while naturally evading constraints from direct detection, collider searches and other multi-messenger observations. Based on the viable non-resonant parameter space identified in previous global fits, we perform a comprehensive study exploring the prospects for discovering such muonphilic DM in the context of a future 3 TeV muon collider, focusing on simplified models with a

\begin{document}$Z_2$\end{document}

-even mediator. Four distinct search strategies are investigated: visible on-shell mediator decays (

\begin{document}$\mu^{+}\mu^{-}\gamma$\end{document}

final state), invisible on-shell mediator decays (mono-photon plus missing energy), mono-photon production via off-shell mediators, and vector boson fusion production.Through a detailed signal-background analysis using cut-and-count methods, we project the exclusion limits at

\begin{document}$ 95 $\end{document}

% confidence level for seven representative models across a wide range of mediator masses. Our results demonstrate that the projected limits cover a significant portion of the viable parameter space that explains the GCE, establishing a muon collider as a decisive machine for testing the muonphilic DM hypothesis.

Structure of the β-Decay Strength Function

I.N. Izosimov

Published:

Abstract:
An analysis of experimental data on measurements of the resonant and fine structure of the β-decay strength function

\begin{document}$S_{\beta}(E)$\end{document}

in spherical, transitional, deformed, and halo nuclei has been conducted. Modern nuclear spectroscopy methods have revealed peak splitting in

\begin{document}$S_{\beta}(E)$\end{document}

for Gamow–Teller (GT) type β-transitions, caused by nuclear deformation. The resonant structure of

\begin{document}$S_{\beta}(E)$\end{document}

for first-forbidden (FF) β-transitions has been experimentally confirmed in both spherical and deformed nuclei. It is shown that at certain nuclear excitation energies, FF β-transitions can reach intensities comparable to those of GT β-transitions. An analysis of the evolution of the energy difference (

\begin{document}$E_{\text {GTR}}{-}E_{\text {IAR}})$\end{document}

between the Gamow–Teller resonance (GTR) and the isobaric analogue resonance (IAR) with increasing neutron excess in nuclei has been performed. A region exhibiting Wigner spin–isospin

\begin{document}$SU(4)$\end{document}

symmetry has been predicted.

Cosmological Perturbation in New General Relativity: Propagating mode from the violation of local Lorentz invariance

Kyosuke Tomonari, Taishi Katsuragawa, Shin'ichi Nojiri

Published: , doi: 10.1088/1674-1137/ae4dd8

Abstract:
We investigate the propagating modes of New General Relativity (NGR) in second-order linear perturbations in the Lagrangian density (first-order in field equations). The Dirac-Bergmann analysis has revealed a violation of local Lorentz invariance in NGR. We review the recent status of NGR, considering the results of its Dirac-Bergmann analysis. We then reconsider the vierbein perturbation framework and identify the origin of each perturbation field in the vierbein field components. This identification is mandatory for adequately fixing gauges while guaranteeing consistency with the invariance ensured by the Dirac-Bergmann analysis. We find that the spatially flat gauge is adequate for analyzing a theory with the violation of local Lorentz invariance. Based on the established vierbein perturbative framework, introducing a real scalar field as matter, we perform a second-order perturbative analysis of NGR with respect to tensor, scalar, pseudo-scalar, and vector and pseudo-vector modes. We reveal the possible propagating modes of each type of NGR. In particular, we find that Type 3 has stable five propagating modes, i.e., tensor, scalar, and vector modes, compared to five non-linear degrees of freedom, which results in its Dirac-Bergmann analysis; The linear perturbation theory of Type 3 is preferable for applications to cosmology. Finally, we discuss our results in comparison to previous related work and conclude this study.

Update analysis of $ \psi(3686)\to p\bar{p}$

Zhi Gao, Rong-Gang Ping, Minggang Zhao

Published: , doi: 10.1088/1674-1137/ae4a0c

Abstract:
We present an updated analysis of the angular distribution for

\begin{document}$ \psi(3686) \to p\bar{p} $\end{document}

decay, taking into account transverse beam polarization, to investigate potential sources of forward-backward asymmetry and azimuthal modulation beyond the simple

\begin{document}$ 1+\alpha\cos^2\theta $\end{document}

form. We focus on the interference between the

\begin{document}$ \psi(3686) $\end{document}

resonance and the two-photon exchange continuum process, as well as the background from initial-state–final-state radiation interference. A maximum-likelihood fit to the

\begin{document}$ \cos\theta $\end{document}

distribution of

\begin{document}$ \psi(3686)\to p\bar{p} $\end{document}

yields

\begin{document}$ \alpha = 1.00 \pm 0.03 $\end{document}

, consistent with previous results. The fitted contributions from the two-photon interference are small but non-negligible, while the ISR–FSR background is negligible. Our model predicts a significant

\begin{document}$ \sin(2\phi) $\end{document}

modulation in the azimuthal angle, indicating the influence of transverse beam polarization. These findings motivate future two-dimensional angular analyses to fully disentangle the polarization and interference dynamics in charmonium decays to baryon pairs.

Next-to-Leading-Order QCD Predictions for the Σ Dirac Form Factors

Bo-Xuan Shi, Hui-Xin Yu, Xue-Chen Zhao

Published:

Abstract:
In this work, we compute the next-to-leading-order QCD corrections to the Dirac electromagnetic form factors of the Σ hyperons within the hard-collinear factorization framework at leading power. The corresponding short-distance coefficient functions are extracted from the relevant seven-point partonic correlation functions. We find that the one-loop radiative corrections to the leading-twist hard-scattering contributions are numerically significant over a broad range of momentum transfer. Combining the perturbatively calculated hard kernels with nonperturbative Σ distribution amplitudes determined from lattice QCD, we present state-of-the-art theoretical predictions for the Σ hyperon electromagnetic form factors.

NLO QCD sum rules analysis of 1⁻⁺ tetraquark states

Wei-Yang Lai, Hong-Ying Jin

Published:

Abstract:
We performed a next-to-leading-order (NLO) QCD sum rules analysis of the

\begin{document}$1^{-+}$\end{document}

light tetraquark states. By investigating various compact and molecular tetraquark currents, we extracted the mass spectra of the corresponding states, all of which lie above

\begin{document}$1.7\,\text{GeV}$\end{document}

. We find multiple

\begin{document}$1^{-+}$\end{document}

states around

\begin{document}$2.0\,\text{GeV}$\end{document}

that match well with

\begin{document}$\pi_{1}(2015)$\end{document}

, which makes us confident that

\begin{document}$\pi_{1}(2015)$\end{document}

is an excellent tetraquark candidate. In contrast, our calculations exclude the possibility that the

\begin{document}$\pi_{1}(1400)$\end{document}

is a tetraquark or hybrid-tetraquark mixture. This suggests that it may not exist, which is consistent with recent experimental results.

Quantum Gravitational Corrections to Reissner-Nordström Black Hole Thermodynamics and Their Implications for the Weak Gravity Conjecture

Yong Xiao, Qiang Wang, Aonan Zhang

Published: , doi: 10.1088/1674-1137/ae457a

Abstract:
In this paper, we investigate the quantum gravitational corrections to the thermodynamical quantities of Reissner-Nordstr?m black holes within the framework of effective field theory. The effective action originates from integrating out massless particles, including gravitons, at the one-loop level. We perform a complete thermodynamic analysis for both non-extremal and extremal black holes and are mainly concerned with the shift in the charge-to-mass ratio

\begin{document}$ q/M$\end{document}

, which plays an important role in analyzing the weak gravity conjecture. For non-extremal black holes, we identify a relationship between the shift in the charge-to-mass ratio and the thermodynamic stability of the black holes. For extremal black holes, we show that quantum gravity effects naturally lead to the super-extremality

\begin{document}$ q/M>1$\end{document}

of charged black holes.

Higgs Decays to Zγ and γγ in the Flavor-Gauged Two Higgs Doublet Model

Feng-Zhi Chen, Qiaoyi Wen, Fanrong Xu

Published:

Abstract:
This work examines the

\begin{document}$ h\to Z\gamma $\end{document}

and

\begin{document}$ h\to\gamma\gamma $\end{document}

decays in the flavor-gauged two Higgs doublet model (FG2HDM), which augments the Standard Model (SM) with an additional scalar doublet, a singlet, and a

\begin{document}$ U(1)' $\end{document}

flavor gauge symmetry. Beyond the SM spectrum, the FG2HDM predicts five additional physical scalars and a new neutral gauge boson,

\begin{document}$ Z' $\end{document}

. We demonstrate that while both decay channels are sensitive to charged Higgs loops,

\begin{document}$ h \to Z\gamma $\end{document}

is uniquely modified by fermion-antifermion-Z (

\begin{document}$ f\bar{f}Z $\end{document}

) vertex corrections. These vertex corrections further impact top-quark observables and the flavor-changing neutral current (FCNC) process

\begin{document}$ b\to s\ell^+\ell^- $\end{document}

. Our analysis identifies a viable parameter space (

\begin{document}$ m_{H^\pm}>200 $\end{document}

GeV and

\begin{document}$ \lambda_{hH^+H^-}<0 $\end{document}

) consistent with current

\begin{document}$ 1\sigma $\end{document}

experimental limits, where the signal strength

\begin{document}$ \mu_{\gamma\gamma} $\end{document}

remains the primary constraint on scalar sector parameters. Regarding the

\begin{document}$ f\bar{f}Z $\end{document}

couplings, we delineate the allowed regions in the

\begin{document}$ \mathcal{Q}_{tL} $\end{document}

-

\begin{document}$ \mathcal{Q}_{tR} $\end{document}

plane by evaluating the leading top-quark contributions, revealing that

\begin{document}$ b\to s\ell^+\ell^- $\end{document}

imposes the most stringent bounds. Finally, we highlight that the

\begin{document}$ 14\% $\end{document}

projected precision for

\begin{document}$ \mu_{Z\gamma} $\end{document}

at the High-Luminosity LHC (HL-LHC) will significantly enhance the sensitivity to the FG2HDM.

Assessing the impact of the electron ion collider in China on Deeply Virtual Compton Scattering

Yuan-Yuan Huang, Xu Cao, Taifu Feng, Krešimir Kumerički, Yu Lu

Published:

Abstract:
We assess the impact of future measurements of deeply virtual Compton scattering (DVCS) off protons using the planned detector at the Electron-Ion Collider in China (EicC), proposed as an upgrade to the High Intensity heavy-ion Accelerator Facility (HIAF). We develop a neural-network architecture to flexibly parameterize the Compton Form Factors (CFFs), extrapolate reliably into unmeasured kinematic regions, and provide robust uncertainty estimates through the replica method. The framework is fitted to the available worldwide DVCS data using the

\begin{document}$ {\mathrm{Gepard}}$\end{document}

software. We find a significant reduction in the uncertainties of all CFFs after incorporating pseudo-data from single and double polarization asymmetries at the EicC, with particularly strong improvements in the sea-quark region.

Negative potential-induced scalarization in the Einstein-Euler-Heisenberg black hole

Hong Guo, Miok Park, Yun Soo Myung

Published:

Abstract:
We investigate a negative potential-induced scalarization of the Einstein-Euler-Heisenberg (EEH) black hole in the EEH-scalar theory, characterized by mass M, Euler-Heisenberg parameter μ and magnetic charge q. In the regime

\begin{document}$ \mu>\mu_{{\rm{max}}} = 0.019 $\end{document}

(with

\begin{document}$ M=1/2 $\end{document}

), the black hole admits a single horizon and allows for overcharged configurations with

\begin{document}$ q/M \gt 1 $\end{document}

. We obtain a single branch of scalarized EEH (sEEH) black holes for

\begin{document}$ q>0 $\end{document}

which is considered as the simplest model for scalarization of EEH black holes. We find that this class of hairy black holes is not thermodynamically favored, and their quasinormal modes indicate they are dynamically unstable. An notable feature is that the scalar charge depends weakly on q for

\begin{document}$ q<1/2 $\end{document}

, but grows more rapidly for

\begin{document}$ q>1/2 $\end{document}

, suggesting a transition from primary- to secondary-type scalar charge. This finding reveals characteristic properties of hairy black holes in EEH theory, specifically in the overcharging regime.

Analytical Study of Fundamental Oscillation Frequencies Around Black Holes in Non-Local Gravity

Rana Muhammad Zulqarnain, Phongpichit Channuie, Abdelmalek Bouzenada, Asifa Ashraf, Farruh Atamurotov, Ikhtiyor Saidov

Published:

Abstract:
In this study, we investigate the dynamics of test particles in the spacetime of a static, spherically symmetric black hole (BH), illustrated within the non-local gravity models. In this case, after presenting the BH geometries and horizon structures, we examine the motion of particles by analyzing the effective potential, the innermost stable circular orbits (ISCOs), and the corresponding effective force. Also, we then extend the study to small perturbations of circular orbits, exploring harmonic oscillations characterized by the frequencies measured both by local observers and by distant ones, as well as the periastron precession effects. Particular attention is devoted to the interplay between the non-local gravity corrections and the stability properties of geodesics. In this case, we analyze the center-of-mass energy (CME) of colliding particles near the event horizon and show the influence of BH parameters on energy extraction processes. In this context, the results show how non-local modifications of gravity affect the standard predictions of BH structure, orbital stability, and high-energy particle dynamics, with possible implications for astrophysical observations and theoretical models of strong gravity. This study examines the differences between the inverse electrodynamics BH and the Schwarzschild BH configuration, showing how additional parameters influence the dynamics and stability of the test particles.

Exploring toroidal α-cluster configurations in ²⁸Si within the 7α cluster model

Su-Yu Zhou, Bo Zhou

Published: , doi: 10.1088/1674-1137/ae4578

Abstract:
Two

\begin{document}$ 7\alpha $\end{document}

cluster configurations in

\begin{document}$ ^{28}\mathrm{Si} $\end{document}

—a uniform toroidal configuration and a disk-like configuration—are investigated within the framework of the generator coordinate method (GCM) with Brink-Bloch 7α wave functions by taking the edge length as the generator coordinate. Within the framework of the 7α cluster model with imposed geometric symmetry, we observe that a uniform toroidal configuration may emerge at approximately 40 MeV above the 7α threshold. This provides a cluster-model perspective that complements some mean-field descriptions of toroidal structure in

\begin{document}$ ^{28}\mathrm{Si} $\end{document}

.

Observational Constraints on Dissipative Chaplygin Gas Cosmology in the Framework of Coincident f(Q) Gravity

Sayantan Ghosh, Raja Solanki, P.K. Sahoo

Published: , doi: 10.1088/1674-1137/ae50e5

Abstract:
In this current work, we shed light on the unified approach to both dark energy and dark matter via the generalized Chaplygin gas model in symmetric teleparallel gravity (STGR). We have employed the equation of state provided by the generalized Chaplygin gas, which naturally arises in string theory, tachyonic field theory, and Randall-Sundrum type brane world solutions. We show that such a generalized Chaplygin gas can not only provide a lucrative candidate for dark energy but also a viable candidate for dark matter via Bose-Einstein Condensation (BEC). We have also taken into account the interaction between dark matter and dark energy to provide a more realistic perspective. We performed MCMC analysis with combined Hubble and Pantheon data sets. We have also performed the Om diagnostics and the

\begin{document}$ r-s $\end{document}

plot to comment on the late behavior of our model. We have also found that through Om diagnostics, the values are in Phantom regions, and we have given physical reasons why this is expected. Finally, we outline some future directions for our work to be carried out.

Multinucleon transfer products in ⁴⁸Ca, ⁵⁴Cr +²⁴³ Am and ⁵⁴Cr +²³⁸ U reactions

G. Xie, Z. Y. Zhang, J. G. Wang, L. Ma, M. H. Huang, C. L. Yang, X. L. Wu, Z. G. Gan, H. B. Yang, M. M. Zhang, Y. L. Tian, Y. S. Wang, J. Y. Wang, Y. H. Qiang, L. Zhu, X. Y. Huang, S. Y. Xu, Z. Zhao, Z. C. Li, X. Zhang, H. Zhou, J. H. Zheng, L. C. Sun, F. Guan, W. X. Huang, Z. Qin, Y. Wang, X. J. Yin, Y. F. Cui, Y. He, L. T. Sun, Z. Z. Ren, S. G. Zhou, V. K. Utyonkov, A. A. Voinov, Yu. S. Tsyganov, A. N. Polyakov, D. I. Solovyev, D. Ibadullayev, M. V. Shumeiko

Published:

Abstract:
Experiments with the ⁴⁸Ca and ⁵⁴Cr induced reactions were performed at the gas-filled recoil separator SHANS2 (Spectrometer for Heavy Atoms and Nuclear Structure-2) of the China Accelerator Facility for superheavy Elements (CAFE2). The isotopic distributions of nuclei produced in the reactions ⁴⁸Ca +²⁴³ Am, ⁵⁴Cr +²⁴³ Am, and ⁵⁴Cr +²³⁸ U were investigated. Bombardments were conducted at the energies near the respective Coulomb barriers, with the SHANS2 magnetic rigidities set to collect fusion-evaporation residues. α-decay spectroscopy was employed to identify products, revealing 58 different isotopes in these experiments. The analysis indicates that the distribution of nuclides produced in different reactions exhibits clear systematic trends. Based on their mass distributions, these nuclei were attributed to the products from the quasi-fission (QF) process. In addition, several short-lived fission events were identified and attributed to the fission isomers near the target.

Bayesian Extraction of HQET Parameters from Inclusive Semi-Leptonic Decay of the Λ_c⁺ Baryon

Dong Xiao, Kangkang Shao

Published:

Abstract:
We extract the non-perturbative Heavy Quark Effective Theory (HQET) parameters from the inclusive semi-leptonic decay

\begin{document}$ \Lambda_c^+ \to X e^+ \nu_e $\end{document}

. Unlike charmed mesons produced near threshold,

\begin{document}$ \Lambda_c^+ $\end{document}

baryons produced in

\begin{document}$ e^+e^- $\end{document}

annihilation exhibit a complex momentum distribution, making the transformation of the electron energy spectrum from the laboratory frame to the

\begin{document}$ \Lambda_c^+ $\end{document}

rest-frame non-trivial. To address this, we develop a novel Bayesian inference method to reconstruct the electron energy moments in the

\begin{document}$ \Lambda_c^+ $\end{document}

rest-frame. By performing a global fit of theoretical predictions in the 1S mass scheme to these extracted moments, we determine the HQET parameters

\begin{document}$ \mu_\pi^2(\Lambda_c^+) $\end{document}

and

\begin{document}$ \rho_D^3(\Lambda_c^+) $\end{document}

for the first time using a purely data-driven approach.

Lepton flavor of four-fermion operator and fermion portal dark matter

Yuxuan He, Gang Li, Jia Liu, Xiao-Ping Wang, Xiang Zhao

Published: , doi: 10.1088/1674-1137/ae4a08

Abstract:
This study investigates the ultraviolet realization of semileptonic four-fermion operator

\begin{document}$ O_{ledq}^{\alpha \beta 11} $\end{document}

that incorporates Majorana dark matter (DM) in both lepton-flavor-conserving (LFC) and lepton-flavor-violating (LFV) scenarios at the one-loop level via box diagram, thereby effectively alleviating the lower bounds on the new physics scale. In addition, we investigate the interplay between model-independent constraints on the Wilson coefficients and DM direct detection, relic density, and collider searches in the context of fermion portal DM model with two mediators. We found that both the projected future constraint on the LFC Wilson coefficient

\begin{document}$ C_{ledq}^{2211}/\Lambda^2< $\end{document}

\begin{document}$ (12.3\; \text{TeV})^{-2} $\end{document}

from the measurements of neutrino non-standard interaction in the next-generation neutrino oscillation experiments, and the LFV constraint

\begin{document}$ C_{ledq}^{1211}/\Lambda^2< \left(2.2\times 10^3\; \text{TeV} \right)^{-2} $\end{document}

from ongoing charged-lepton-flavor-violation searches, provide a complementary exploration of the parameter space encompassing the DM and scalar masses. With a colored mediator mass of approximately

\begin{document}$ 2\; \text{TeV} $\end{document}

, the sensitivity of the indirect constraints on the four-fermion operator can surpass those of collider searches and DM direct detection, in scenarios where the masses of the DM and scalar are close. By ensuring the correct DM relic density, however, we find that the collider searches and DM direct detection are more sensitive to the electroweak-scale DM and scalar than indirect constraints.

Minimal lepton models with non-holomorphic modular A₄ symmetry

Xiang-Yan Gao, Cai-Chang Li

Published:

Abstract:
We present a comprehensive bottom-up analysis of lepton mass and mixing based on the non-holomorphic

\begin{document}$A_{4}$\end{document}

modular symmetry. Neutrinos are assumed to be Majorana particles and the light neutrino masses are generated through the Weinberg operator. In this framework, we construct all phenomenologically viable models with minimal number of free parameters, where the Yukawa couplings are expressed in terms of polyharmonic Maa? forms of weights

\begin{document}$\pm4$\end{document}

,

\begin{document}$\pm2$\end{document}

and 0 at level

\begin{document}$N=3$\end{document}

. Without imposing generalized CP (gCP) symmetry, we identify 147 (6) viable models with eight real free parameters that successfully reproduce the current experimental data of lepton sector for the normal (inverted) mass ordering. When gCP symmetry consistent with

\begin{document}$A_{4}$\end{document}

modular symmetry is included, the number of free parameters is reduced by one, yielding 47 (5) phenomenologically viable models in the normal (inverted) mass ordering. Finally, we present detailed numerical analyses of a representative model for both mass orderings to illustrate these results.

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: , doi: 10.1088/1674-1137/ad8ec2

Abstract:
The direct CP asymmetry in the weak decay process of hadrons is commonly attributed to the weak phase of the CKM matrix and the indeterminate strong phase. We propose a method to generate a significant phase difference through the interference between ρ and ω mesons, taking into account the G-parity allowed decay process of

\begin{document}$\omega \rightarrow \pi^{+}\pi^{-}\pi^{0}$\end{document}

and the G-parity-suppressed decay process of

\begin{document}$\rho^{0} \rightarrow \pi^{+}\pi^{-}\pi^{0}$\end{document}

in B meson decays. This interference can lead to notable changes in the CP asymmetry within the interference region. Additionally, we calculate the integral results for different phase space regions of the four-body decay process. We hope that our work provides valuable theoretical guidance for future experimental investigations on CP asymmetry in these decays.

Systematic study of microscopic nuclear level densities of Sn isotopes within a relativistic framework

Guanbin He, Nuocheng Tang, Yuan Tian, Ying Cui, Jian Li, Yi Xu, Ruirui Xu

Published: , doi: 10.1088/1674-1137/ae4329

Abstract:
Nuclear level density (NLD) plays a crucial role in describing the statistical properties of excited nuclei and is a key input for models of compound nuclear reactions, such as those used in nuclear astrophysics and reactor physics. In this work, we construct microscopic nuclear level densities for Sn isotopes by combining single-particle spectra, pairing correlations, and deformation parameters from relativistic Hartree–Bogoliubov (RHB) calculations with the combinatorial method. We examine the energy dependence and isotopic systematics of the calculated level densities. In particular, we analyze their variation with excitation energy and neutron number, and compare them to available experimental data, including cumulative low-lying levels and s-wave neutron resonance spacings (

\begin{document}$ D_0 $\end{document}

). The resulting level densities are further employed as input to Hauser–Feshbach calculations of radiative neutron capture

\begin{document}$ (n,\gamma) $\end{document}

cross sections [55]. Our results demonstrate that RHB-based nuclear level densities provide a reliable microscopic framework for describing Sn isotopic level densities and accurately predicting

\begin{document}$ (n,\gamma) $\end{document}

cross sections.

The perturbation solutions to the Blandford-Znajek mechanism in the Kerr-Sen black hole

Haiyuan Feng, Ziqiang Cai, Rong-Jia Yang, Jinjun Zhang

Published:

Abstract:
We investigate the steady, axisymmetric, force-free magnetosphere of Kerr–Sen black hole (BH) within the framework of the Einstein–Maxwell–dilaton–axion (EMDA) theory. By perturbatively solving the nonlinear Grad–Shafranov (GS) equation, we determine the magnetic field configuration and quantify the influence of the dilaton parameter r₂ on the energy extraction rate and radiative efficiency. Our results show that both the energy extraction power and the radiative efficiency increase with r₂, exceeding those of the standard Kerr BH, whereas the extraction efficiency remain consistent with the Kerr case. In addition, we perform χ² statistical analysis using observational data from six binary BH systems, which indicates that the Kerr BH currently provides a better fit for bulk Lorentz factors Γ = 2 and 5.

Just Accepted