Chinese Physics C

Mixed large field inflation emerging from a quantum bounce in loop quantum cosmology

Yerlan Myrzakulov

Published: , doi: 10.1088/1674-1137/ae5c84

Abstract:
We study the pre-inflationary evolution of the universe within the framework of loop quantum cosmology for a scalar field with potential

\begin{document}$ V(\phi)=M^{4}\frac{\phi^{2}}{M_{Pl}^{2}}\left(1+\alpha\frac{\phi^{2}}{M_{Pl}^{2}}\right) $\end{document}

, where α is a positive constant. In this framework, the classical initial singularity is resolved and replaced by a non-singular quantum bounce occurring at a critical energy density. Starting from the bounce, we analyze the background dynamics for both kinetic-energy-dominated and potential-energy-dominated initial conditions. Our results show that slow-roll inflation with a sufficient number of e-folds emerges generically over a wide range of initial inflaton values. We further examine the associated phase portrait and demonstrate the attractor behavior of the slow-roll inflationary solutions. Additionally, we study the spectral index

\begin{document}$ n_s $\end{document}

and the tensor-to-scalar ratio r for three limiting cases of α, finding that the model is observationally viable in the intermediate regime.

Measurement of differential and angle-integrated cross sections for the ¹⁰B(n, α)⁷Li reaction from 0.3 eV to 3.0 MeV at CSNS Back-n

Wenkai Ren, Han Yi, Haofan Bai, Jie Liu, Kang Sun, Wei Jiang, Zepeng Wu, Cong Xia, Guohui Zhang, Yonghao Chen, Ruirui Fan, Qiwen Fan, Shixiang Peng, Wentian Cao, Tieshuan Fan

Published: , doi: 10.1088/1674-1137/ae5dae

Abstract:
In the present work, new measurements of differential and angle-integrated cross sections for the ¹⁰B(n, α₁)⁷Li^*, ¹⁰B(n, α₀)⁷Li and ¹⁰B(n, α)⁷Li reactions were performed at CSNS Back-n white neutron source. The Light-charged Particle Detector Array (LPDA) system was used to detect the charged particles. The ⁶Li-Si monitor was employed to measure the neutron flux. The differential cross sections for the ¹⁰B(n, α)⁷Li reaction were obtained from 20.2^o to 158.7^o (13 angles) in the neutron energy region from 0.3 eV to 3.0 MeV (70 energy points). The differential cross sections for the ¹⁰B(n, α₀)⁷Li and ¹⁰B(n, α₁)⁷Li^* reactions were also obtained at the same angular positions in the neutron energy region from 0.3 eV to 1.0 MeV (65 energy points). Fitting with the Legendre polynomial series, the angle-integrated cross sections of these three reactions were obtained through integration. The experimental data for these three reactions across such a wide neutron energy range are valuable references for future nuclear data evaluations.

Prospects for discovering strongly decaying doubly heavy T_bc tetraquark states at LHCb

Mingjie Feng, Yiming Li, Hua-Sheng Shao

Published: , doi: 10.1088/1674-1137/ae5a87

Abstract:
We investigate the discovery potential of the

\begin{document}$T_{bc}$\end{document}

state with

\begin{document}$J^P = 0^+$\end{document}

in proton-proton (

\begin{document}$pp$\end{document}

) collisions at LHCb at a center-of-mass energy of

\begin{document}$\sqrt{s} = 13~{\rm{TeV}}$\end{document}

. The study focuses on the decay channel

\begin{document}$T_{bc} \to B^- D^+$\end{document}

. A phenomenological approach is employed to construct the background model based on the associated production of B and D mesons, incorporating previously published LHCb results. Background processes are simulated using

\begin{document}${\mathtt{MadGraph5\_aMC@NLO}}$\end{document}

and

\begin{document}${\mathtt{Pythia8.3}}$\end{document}

. We explore the parameter space of the

\begin{document}$T_{bc}$\end{document}

mass, width, production cross section, and the effective double-parton scattering cross section (

\begin{document}$\sigma_{{\rm{eff}}}$\end{document}

) relevant for the

\begin{document}$B D$\end{document}

meson background. The integrated luminosity required for a

\begin{document}$5\sigma$\end{document}

discovery at LHCb is evaluated under various assumptions. In particular, we consider three representative

\begin{document}$T_{bc}$\end{document}

production cross section scenarios: an optimistic estimate of

\begin{document}$103~{\rm{nb}}$\end{document}

, an intermediate value of

\begin{document}$18~{\rm{nb}}$\end{document}

obtained by scaling from the

\begin{document}$T_{cc}^+$\end{document}

production cross section, and a conservative lower bound of

\begin{document}$0.3~{\rm{nb}}$\end{document}

. We find that a

\begin{document}$5\sigma$\end{document}

observation is achievable for a production cross section of

\begin{document}$103~{\rm{nb}}$\end{document}

, which is expected to be within reach during Run~4. In contrast, the more realistic cross section estimate of

\begin{document}$18~{\rm{nb}}$\end{document}

requires the full Run~5 dataset (

\begin{document}$300~{\rm{fb}}^{-1}$\end{document}

) under the most favorable parameter choices. For the conservative scenario, no significant signal would be observable even with

\begin{document}$300~{\rm{fb}}^{-1}$\end{document}

. In addition, we estimate the minimum observable

\begin{document}$\sigma(T_{bc}) \times {\cal{B}}(T_{bc} \to B^- D^+)$\end{document}

for a

\begin{document}$5\sigma$\end{document}

discovery under different luminosity scenarios, providing guidance for future experimental searches at LHCb.

Systematic study of odd-even staggering in elemental fragmentation cross sections for N=Z nuclei from ³⁶Ar to ²⁸Si at ~ 300 MeV/nucleon

Yu-Nan Song, Yong Zheng, Guang-Shuai Li, Bao-Hua Sun, Jun Su, Ge Guo, Kai-Long Wang, Jun-Yao Xu, Xiao-Dong Xu, Ji-Chao Zhang, Meng Wang, Xiu-Lin Wei, Yong Cao, Bing-Shui Gao, Yun Qin, Lu-Ping Wan, Chang-Jian Wang, Xin-Xu Wang, Wen-Wen Zhang, Xiao-Bin Zhang, Zi-Cheng Zhou

Published: , doi: 10.1088/1674-1137/ae5d27

Abstract:
Elemental fragmentation cross sections (EFCSs) of the

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

nuclei

\begin{document}$^{36}$\end{document}

Ar,

\begin{document}$^{34}$\end{document}

Cl,

\begin{document}$^{32}$\end{document}

S,

\begin{document}$^{30}$\end{document}

P, and

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

Si on a carbon target were measured at approximately 300 MeV/nucleon using the RIBLL2 fragment separator at HIRFL. Among these, the cross sections for

\begin{document}$^{34}$\end{document}

Cl and

\begin{document}$^{30}$\end{document}

P are reported here for the first time, providing new data and extending EFCS measurements along the

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

chain. The measured cross sections exhibit significant odd-even staggering as a function of the charge change

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

. The experimental results are compared with several empirical parametrizations, including Cummings, EPAX3, and FRACS, as well as with the isospin-dependent quantum molecular dynamics model (IQMD) coupled to the statistical decay code GEMINI. The IQMD+GEMINI calculations reproduce the experimental cross sections with an accuracy of approximately 7% and reasonably reproduce the observed odd-even staggering. Consistent with previous studies, comparisons between model predictions at different reaction stages demonstrate that the odd-even staggering in EFCSs predominantly originates from the de-excitation of excited primary fragments. These results further establish the robustness of this interpretation by extending its validation to the

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

region.

Sensitivity study of $\bar{K}_1(1270)$ decay dynamics using four $D\to \bar{K}_1(1270)(\to \bar K\pi\pi)e^+\nu$ decay channels

Ying'ao Tang, Liang Sun, Panting Ge, Menghao Wang

Published: , doi: 10.1088/1674-1137/ae5c70

Abstract:
A sensitivity study of

\begin{document}$ \bar{K}_1(1270) $\end{document}

decay-mode measurements is performed using semileptonic D-meson decays. The BESIII experiment is used as a case study, in which a simultaneous analysis of

\begin{document}$ \bar{K}_1(1270) $\end{document}

decays to the four three-body final states

\begin{document}$ K^-\pi^+\pi^- $\end{document}

,

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

,

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

, and

\begin{document}$ K_S^0\pi^-\pi^0 $\end{document}

is presented, and a model-independent determination of

\begin{document}$ {\cal{B}}(\bar{K}_1(1270)\to \bar K\pi\pi) $\end{document}

that does not require detailed knowledge of intermediate resonant contributions is proposed.

Revisiting critical orbits of test particles traveling in a black hole background

Ping Li, Jun Cheng, Jiang-he Yang

Published: , doi: 10.1088/1674-1137/ae5d29

Abstract:
This paper systematically revisits the critical orbits of test particles in various black hole backgrounds, including Schwarzschild, Reissner–Nordströom, Kerr, and Kerr–Newman spacetimes. We identify the critical orbits directly from the root structure of the radial equation, and we provide explicit expressions that relate the relevant parameters—energy, angular momentum, and charge-to-mass ratio—to the critical radius, as well as explicit formulas for the critical orbits in each case. Special attention is given to the relationships among the photon spheres, black hole shadows, and critical null geodesics. We also present extensive numerical results.

Relativistic corrections to hadron-hadron scattering phase shift and correlation function

Zeyu Zeng, Baoyi Chen, Jiaxing Zhao

Published: , doi: 10.1088/1674-1137/ae5884

Abstract:
Femtoscopy offers a sensitive probe of hadron emission sources and hadronic interactions. In this study, we examine relativistic corrections to scattering phase shifts and correlation functions using the two-body Dirac equation framework. We analyze the impact of the Darwin term and spin-dependent potentials, showing that these relativistic effects, especially spin-related interactions, significantly enhance the proton-proton correlation function. Our findings emphasize the necessity of including relativistic corrections for precise femtoscopic analyses.

Nonlinear diffusive shock acceleration with upstream escape reproduces DAMPE observations

Han-Xiang Hu, Xing-Jian Lv, Xiao-Jun Bi, Tian-Lu Chen, Kun Fang, Peng-Fei Yin

Published: , doi: 10.1088/1674-1137/ae5c7d

Abstract:
We develop a self-consistent nonlinear extension of diffusive shock acceleration that incorporates cosmic-ray (CR) backreaction on the shock precursor together with a physically motivated upstream escape mechanism that yields an exponential high-energy cutoff. The CR pressure gradient decelerates the upstream flow ahead of the shock, generating an extended precursor in which higher-rigidity particles sample a larger cumulative velocity gradient and thereby acquire a progressively harder spectrum. Finite-size and escape effects are modeled by a momentum-dependent loss term, which naturally terminates acceleration and steepens the spectrum near the cutoff. The precursor compression ratio is not imposed as a closure condition; instead, it is determined dynamically by enforcing consistency between the injection rate inferred from thermal leakage at the subshock and the injection strength required by the nonlinear shock modification, with CR-driven wave heating providing stabilizing negative feedback. Applying the model to young supernova-remnant–like parameters and standard one-zone Galactic diffusion, we reproduce the main features of the latest DAMPE proton spectrum: gradual hardening from hundreds of GeV to multi-TeV energies, followed by an exponential cutoff at tens of TeV. The resulting spectral evolution follows directly from the competition between precursor-mediated nonlinear feedback and upstream escape.

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.

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.

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}

.

Design of LACT Detector Layout and Expectation for Gamma-ray Sources Observation

Wei Liu, Jiali Liu, Shoushan Zhang, Yun Zhang, Zhipeng Zhang, Ruizhi Yang, Yudong Wang, Zhen Min, Shaohui Feng, Lisi Geng, Zhen Cao

Published: , doi: 10.1088/1674-1137/ae5c6f

Abstract:
The Large Array of imaging atmospheric Cherenkov Telescopes (LACT) is a next-generation Cherenkov telescope array designed to study the morphology and energy spectra of ultra-high-energy gamma-ray sources in hybrid operation with the Large High Altitude Air Shower Observatory (LHAASO). With its excellent angular resolution, large effective area, and powerful gamma/hadron discrimination capabilities, LACT achieves outstanding sensitivity for observations of gamma-ray sources In this paper, we present an optimized configuration for the LACT array, developed through comprehensive Monte Carlo simulations. Based on these simulations, we conducted on-site surveys at the LHAASO site and selected the most effective array layout. Detailed performance studies show that this optimized configuration delivers excellent sensitivity across various observational modes. Furthermore, we present a detailed outlook on LACT's potential observations of gamma-ray sources in the LHAASO catalog. By incorporating the measured energy spectra from LHAASO and accounting for LACT's detector response function at different zenith angles, we estimate the number of detectable events over a one-year observation period. This analysis provides a foundation for developing a preliminary observation strategy for LACT in the coming years.

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.

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.

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.

Just Accepted