Chinese Physics C

Comprehensive investigation on baryon number violating nucleon decays involving an axion-like particle

Wei-Qi Fan, Yi Liao, Xiao-Dong Ma, Hao-Lin Wang

Published: , doi: 10.1088/1674-1137/ae25c9

Abstract:
In this work, we systematically investigate baryon number violating (BNV) nucleon decays into an axion-like particle (ALP), within a low energy effective field theory extended with an ALP, named as aLEFT. Unlike previous studies in the literature, we consider contributions to nucleon decays from a complete set of dimension-eight BNV aLEFT operators involving light u, d, s quarks. We perform the chiral irreducible representation (irrep) decomposition of all those interactions under the QCD chiral group

\begin{document}${\rm{SU}}(3)_{\mathtt{L}}\times {\rm{SU}}(3)_{\mathtt{R}}$\end{document}

, and match them onto the recently developed chiral framework to obtain nucleon-level effective interactions among the ALP, octet baryons, and octet pseudoscalar mesons. Within this framework, we derive general expressions for the decay widths of nucleon two- and three-body decays involving an ALP. We then analyze the momentum distributions for the three-body modes and find that the operators belonging to the newly identified chiral irreps

\begin{document}${\bf{6}}_{{\mathtt{L}}({\mathtt{R}})}\times {\bf{3}}_{{\mathtt{R}}({\mathtt{L}})}$\end{document}

exhibit markedly different behavior compared to that in the usual irreps

\begin{document}${\bf{8}}_{{\mathtt{L}}({\mathtt{R}})}\times \pmb{1}_{{\mathtt{R}}({\mathtt{L}})}$\end{document}

and

\begin{document}${\bf{3}}_{{\mathtt{L}}({\mathtt{R}})}\times \bar{{\bf{3}}}_{{\mathtt{R}}({\mathtt{L}})}$\end{document}

. Furthermore, due to the lack of direct constraints on those exotic decay modes, we reanalyze the experimental data collected by Super-Kamiokande and establish bounds on the inverse decay widths of these new modes by properly accounting for experimental efficiencies and Cherenkov threshold effects. Our recasting constraints are several orders of magnitude more stringent than the inclusive bounds used in the literature. Based on these improved bounds, we set conservative limits on the associated effective scales across a broad range of ALP mass and predict stringent bounds on certain neutron and hyperon decays involving an ALP.

A Study on the Triggering of Nucleonic Direct Urca Processes in Neutron Stars of Specific Masses and Their Hyperon Dependence

Y. Xu, Y. F. Shen, Q. Yuan, X. L. Huang, Y. B. Wang

Published:

Abstract:
This work aims to analyze how hyperons affect neutrino radiation properties in nucleonic direct URCA processes, with the goal of providing useful references for identifying evidence of hyperons in astronomical observations. This analysis is conducted using the GM1 and NL3 parameter sets under the SU(6) and SU(3) flavor symmetries within the relativistic mean field theory framework. In conjunction with the inferred mass and radius values of PSRs J1231-1411, J0030+0451, and J0740+6620, our results indicate that nucleonic direct URCA processes are absent in PSR J1231-1411 due to momentum conservation violation. In the hyperon-containing PSR J0030+0451 (NL3 parameter set), the nucleonic direct URCA processes involving

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

/

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

would occur. A large inferred mass span induces hyperon fraction variations, which affect neutrino emissivity. If the inferred mass of PSR J0030+0451 exceeds approximately 1.8

\begin{document}$M_{\odot}$\end{document}

, the neutrino luminosity of the nucleonic direct URCA processes under the SU(3) flavor symmetry remains nearly the same as that in npeµ matter, independent of hyperons. However, it shows an obvious hyperon dependence under the SU(6) spin-flavor symmetry. For hyperon-containing J0740+6620, the nucleonic direct URCA processes under the SU(3) flavor symmetry in the GM1 parameter set predict a faster decline in neutrino luminosity with the hyperonic fraction than in npeµ matter, and under the SU(6) spin-flavor symmetry in the NL3 parameter set, it shows a monotonic decreasing trend. The research indicates that the hyperonic fraction significantly affects the neutrino radiation properties of nucleonic direct URCA processes in neutron stars. Different-mass pulsars (e.g., PSRs J1231-1411, J0030+0451, J0740+6620) exhibit distinct behaviors of nucleonic direct URCA processes, depending on inferred masses/radii, parameter sets, and theoretical models.

B(E2;2₁⁺→0₁⁺) anomaly in ¹⁶⁶Os

Chen-guang Zhang, Suo-chang Jin, Tie Wang, Tao Wang

Published: , doi: 10.1088/1674-1137/ae1f7a

Abstract:
Recently, the very small

\begin{document}$B(E2;2_{1}^{+}\rightarrow0_{1}^{+})$\end{document}

value of 7(4) W.u. in

\begin{document}$^{166}{\rm{Os}}$\end{document}

was found experimentally. This result is much smaller than the values of 74(13) W.u. and 97(9) W.u. in the adjacent nuclei

\begin{document}$^{168,170}{\rm{Os}}$\end{document}

. Using the newly proposed technique called "SU(3) analysis" and the new explanatory framework for the B(E2) anomaly, the

\begin{document}$B(E2;2_{1}^{+}\rightarrow0_{1}^{+})$\end{document}

anomaly in

\begin{document}$^{166}{\rm{Os}}$\end{document}

is studied for the first time. Four results are used to fit the experimental data in

\begin{document}$^{166,168,170}{\rm{Os}}$\end{document}

successfully. This implies that the level-crossing or level-anticrossing explanation is applicable.

Towards New Elements: Production of Superheavy Elements with ⁵⁰Ti and ⁵⁴Cr

Jia-Xing Li, Fang-Yu Chen, Hong-Fei Zhang

Published: , doi: 10.1088/1674-1137/ae039d

Abstract:
The theoretical study aims to synthesize superheavy elements with

\begin{document}$ Z \geq 114 $\end{document}

by irradiating an actinide target with a beam heavier than

\begin{document}$^{48}\text{Ca}$\end{document}

. The results of the

\begin{document}$ \mathrm{^{244}Pu}(\mathrm{^{50}Ti}, \, \mathit{x} n)\, \mathrm{^{294-\mathit{x}}Lv} $\end{document}

reaction are in good agreement with the experimental results first published by Lawrence Berkeley National Laboratory. The research indicates that reactions using

\begin{document}$ \mathrm{^{50}Ti} $\end{document}

have higher cross sections for the production of superheavy elements compared to reactions using

\begin{document}$ \mathrm{^{54}Cr} $\end{document}

. The production cross section for the

\begin{document}$ \mathrm{^{249}Bk}(\mathrm{^{50}Ti}, \, \mathit{x} n)\, \mathrm{^{299-\mathit{x}}119} $\end{document}

reaction is predicted to be

\begin{document}$ \sigma_{\mathrm{prod}} = 21.72 $\end{document}

fb at a center-of-target center-of-mass energy of 226(2) MeV, while for the

\begin{document}$ \mathrm{^{249}Cf}(\mathrm{^{50}Ti}, \, \mathit{x} n)\, \mathrm{^{299-\mathit{x}}120} $\end{document}

reaction, it is predicted to be

\begin{document}$ \sigma_{\mathrm{prod}} = 1.80 $\end{document}

fb at a higher center-of-target center-of-mass energy of 233(2) MeV. This suggests that with a

\begin{document}$ \mathrm{^{50}Ti} $\end{document}

beam, there is potential for synthesizing superheavy elements near the island of stability, as well as new elements beyond

\begin{document}$ Z = 118 $\end{document}

.

Fragmentation of neutron-rich carbon isotopes on light targets at 27.5 MeV/nucleon

Zi-Yao Hu, Yan-Lin Ye, Jian-Ling Lou, Zai-Hong Yang, Xiao-Fei Yang, Li-Sheng Yang, Wei-Liang Pu, Kang Wei, Ying Chen, Hong-Yu Zhu, Bo-Long Xia, Jia-Xing Han, Jia-Hao Chen, Kai Ma, Dong-Xi Wang, Hao-Yu Ge, Wen-Wu Wan, Jia-Wei Bian, Ze-Yu Du, Zhe-Yang Lin, Qi-Te Li, Zhi-Huan Li, Ong-Hooi Jin, Yan-Yun Yang, Shi-Wei Xu, Jun-Bing Ma, Zhen Bai, Kang Wang, Fang-Fang Duan, He-Run Yang, Peng Ma, Xiang-Lun Wei, Tian-Li Qiu

Published:

Abstract:
Experimental and theoretical investigation of the fragmentation reaction in Fermi-energy domain is currently of particular importance for not only the nuclear physics but also some interdisciplinary fields. In the present work, neutron-rich ¹⁴C and ¹⁶C ion beams at 27.5 MeV/nucleon were used to bombard carbon and polyethylene (CD₂)_n targets. Energy and angular distributions of the produced fragments were measured. Background events originating from the carbon content in (CD₂)_n target were efficiently excluded using an extended E-P plot method. Experimental results are systematically analyzed by using HIPSE-SIMON dynamic model. The comparison reveals that, for the carbon target, the HIPSE-SIMON calculation overestimates the yields of the beam-velocity component for fragments near the projectile and also the energy phase space for fragments far away from the projectile, suggesting fine tuning of the overall interaction profile adopted in the model. In contrast, for reactions with the deuteron target, the model calculation can reasonably reproduce the experimental data. The implication of the fragmentation mechanism to the validity of the invariant mass method, as frequently used to reconstruct the clustering resonant structures in light nuclei, is also discussed.

Deep Learning to Improve the Sensitivity of Higgs Pair Searches in the 4b Channel at the LHC

Yongcheng Wu, Liang Xiao, Yan Zhang

Published:

Abstract:
The Higgs self-coupling is crucial for understanding the structure of the scalar potential and the mechanism of electroweak symmetry breaking. In this work, utilizing deep neural network based on Particle Transformer that relies on attention mechanism, we present a comprehensive analysis of the measurement of the trilinear Higgs self-coupling through the Higgs pair production with subsequent decay into four b-quarks (

\begin{document}$ HH\to b\bar{b}b\bar{b} $\end{document}

) at the LHC. The model processes full event-level information as input, bypassing explicit jet pairing and can serves as an event classifier. At HL-LHC, our approach constrains the

\begin{document}$ \kappa_\lambda $\end{document}

to

\begin{document}$ (-0.25,5.41) $\end{document}

at 68% CL achieving around 44% improvement in precision over conventional cut-based analyses. Comparison against alternative machine learning architectures also shows the outstanding performance of the Transformer-based model, which is mainly due to its ability to capture the correlations in the high-dimensional collision data with the help of attention mechanism. The result highlights the potential of attention-based networks and the end-to-end event classifier in collider phenomenology.

New determination of astrophysical ²⁶Mg(p, γ)²⁷Al reaction rate through the ²⁶Mg(⁷Li, ⁶He)²⁷Al transfer reaction

Yu-Wen Chen, Yun-Ju Li, Bing Guo, Sheng-Quan Yan, Chao Dong, Dan-Yang Pang, Guo Yang, Yang Zhang, Yu-Qiang Zhang, Jun-Wen Tian, Jia-Ying-Hao Li, Fu-Qiang Cao, Wei Nan, Jiang-Lin Hou, Ming-Hao Zhu, Zhi-Cheng Zhang, Chang-Xin Guo, Chen Chen, Yu-Chen Jiang, Yang-Ping Shen, Zhi-Hong Li, You-Bao Wang, Sheng Zeng, Wei-Ping Liu

Published: , doi: 10.1088/1674-1137/ae1f06

Abstract:
The ²⁶Mg

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

²⁷Al reaction, as part of the Mg-Al cycle, is closely related to the abundance ratio of ²⁶Al to ²⁷Al in stars. It also has a direct connection to the Mg-Al anti-correlation observed in globular clusters (GCs). Its reaction rate is determined by multiple known and unknown low-energy resonances. In this work, we measured the angular distributions of the proton transfer reaction ²⁶Mg(⁷Li, ⁶He)²⁷Al populating three levels at excitation energies from 8.324 MeV to 8.597 MeV using the HI-13 tandem accelerator and a high-precision magnetic spectrograph. Proton spectroscopic factors were extracted from the angular distributions corresponding to these three states, and the resonance strengths contributing to the reaction rate were updated. At the same time, the latest calculated reaction rate shows that the result for the 52.8 keV resonance significantly increases the total reaction rate at

\begin{document}$T_{9}<0.03$\end{document}

.

Neutron Leakage Spectra Benchmark of Spherical Polyethylene Sample with a ²⁵²Cf fission Source

Chang-Lin Lan, Kuo-Zhi Xu, Yu-Ting Wei, Yang-Bo Nie, Xiao-Dong Pan, Yan-Yan Ding, Shi-Yu Zhang, Hao-Nan Li, Bo Gao, Bo Xie, Xi-Chao Ruan, Shi-Long Liu

Published:

Abstract:
This study presents the development and validation of China’s first benchmark measurement system for neutron leakage time-of-flight (TOF) spectra using a ²⁵²Cf spontaneous fission source and a spherical polyethylene sample. EJ-309 and CLYC scintillation detectors were used for neutron detection, and a shadow cone was employed for background suppression. Notably, the SiC detector was, for the first time on this platform, applied as the start-time signal generator in TOF spectrum measurement. The TOF spectrum covering the energy range of 0.15-8.00 MeV was measured, and the results were systematically compared with evaluated data from four major nuclear libraries: ENDF/B-VIII.1, JEFF-3.3, JENDL-5, and CENDL-3.2. The comparison revealed strong agreement across the full spectrum, with calculated to experimental(C/E) deviations remaining within 5% in the high-energy region and within 13% at low energies. These results verify the system’s stability and suitability for integral experiments. The established benchmark platform provides a strong technical foundation for future neutron nuclear data validation, particularly in shielding applications and the improvement of fission-spectrum nuclear databases.

Interplay of Lyapunov exponents, phase transitions and chaos bound in nonlinear electrodynamics black hole

Chuanhong Gao, Chuang Yang, Tetvui Chong, Deyou Chen

Published: , doi: 10.1088/1674-1137/ae210d

Abstract:
In this paper, we investigate Lyapunov exponents of chaos for both massless and charged particles around a non-linear electrodynamics black hole, and explore their relationships with a phase transition and a chaos bound of this black hole. Our results indicate that these exponents can effectively reveal the phase transition. Specifically, during the phase transition, the violation of the chaos bound occurs solely within a stable branch of a small black hole. Moreover, regardless of whether the phase transition takes place, the violations are observed.

95 GeV Higgs boson and nano-Hertz gravitational waves from domain walls in the N2HDM

Haotian Xu, Yufei Wang, Xiao-Fang Han, Lei Wang

Published: , doi: 10.1088/1674-1137/ae2082

Abstract:
We explore the diphoton and

\begin{document}$b\bar{b}$\end{document}

excesses at 95.4 GeV, as well as nano-Hertz gravitational waves originating from domain walls, within the framework of the next-to-two-Higgs-doublet model (N2HDM), which extends the two-Higgs-doublet model by introducing a real singlet scalar subject to a discrete

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

symmetry. The

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

symmetry is spontaneously broken by the non-zero vacuum expectation value of the singlet scalar,

\begin{document}$v_s$\end{document}

, which leads to the formation of domain walls. We discuss two different scenarios: in scenario A, the 95.4 GeV Higgs boson predominantly originates from the singlet field, while in scenario B, it arises mainly from the CP-even components of the Higgs doublets. Taking into account relevant theoretical and experimental constraints, we find that scenario A can fully account for both the diphoton and

\begin{document}$b\bar{b}$\end{document}

excesses at 95.4 GeV within the

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

range. In the parameter space accommodating both excesses, scenario A fails to provide a valid explanation for the NANOGrav data up to

\begin{document}$v_s=$\end{document}

1000 TeV, and the predicted gravitational wave spectrum can exceed the SKA sensitivity curve in the low frequency region. Scenario B only marginally accounts for the diphoton and

\begin{document}$b\bar{b}$\end{document}

excesses at the

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

level, but it can simultaneously explain the NANOGrav data well.

Microscopic modeling of proton radioactivity through Hartree-Fock-Bogolyubov calculations with Gogny interaction

M. Ismail, A. Adel, A. Y. Ellithi, M. A. Abbas

Published: , doi: 10.1088/1674-1137/ae1f07

Abstract:
In this work, we perform a microscopic study of proton decay half-lives in neutron-deficient nuclei using the Hartree-Fock-Bogolyubov (HFB) approach with the Gogny D1S effective interaction. Proton emission half-lives from both ground and isomeric states are computed employing a single-folding potential constructed from the realistic M3Y-Paris nucleon-nucleon interaction. The deformed density distributions of the daughter nuclei are calculated self-consistently within the same HFB framework. The resulting decay half-lives are systematically compared with recent experimental measurements and other theoretical models to evaluate the accuracy and predictive capacity of this fully microscopic methodology in describing proton radioactivity near the proton dripline.

Discovery Prospects for a Leptophilic Gauge Boson Z_ℓ at CEPC and ILC

S.O. Kara

Published:

Abstract:
We investigate the discovery prospects of a leptophilic gauge boson

\begin{document}$ Z_\ell $\end{document}

at future

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

colliders, focusing on a comparative study of the Circular Electron–Positron Collider (CEPC) and the International Linear Collider (ILC). Such a state naturally arises from an additional

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

gauge symmetry, under which quarks remain neutral while all leptons carry a universal charge, motivated by neutrino oscillations and scenarios of physics beyond the Standard Model (SM). As a clean benchmark, we study the process

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

, including realistic effects of initial-state radiation (ISR) and beamstrahlung (BS). Our results indicate that CEPC, with its very high luminosity at

\begin{document}$ \sqrt{s}=240 $\end{document}

GeV, can probe couplings down to

\begin{document}$ g_\ell \approx 10^{-3} $\end{document}

for

\begin{document}$ Z_\ell $\end{document}

masses up to about 220 GeV, while the ILC extends the sensitivity to heavier states in the multi-hundred GeV range through its higher

\begin{document}$ \sqrt{s} $\end{document}

stages. These findings demonstrate the strong complementarity of circular and linear colliders in exploring purely leptophilic interactions.

Hyperons in neutron-star cores: confronting maximum mass observational constraint of 2M_⊙

Anuj Sharma, Mukul Kumar, Raj K. Jagota, Shashi K. Dhiman

Published:

Abstract:
We employ a comprehensive set of relativistic mean-field (RMF) models to investigate the role of hyperons (Λ,

\begin{document}$ \Sigma^{\pm,0} $\end{document}

, and

\begin{document}$ \Xi^{-,0} $\end{document}

) in dense nuclear matter. We consider various RMF models that span a wide range of high-density behaviors of equations of state, symmetry energy coefficients, and hyperon-meson coupling schemes. Our aim is to assess how the inclusion of hyperons in the nucleonic matter influences the key neutron star properties, including the maximum mass (M

\begin{document}$ _{max} $\end{document}

), stellar radius (R

\begin{document}$ _{max} $\end{document}

), and tidal deformability (

\begin{document}$ \Lambda_{max} $\end{document}

). By varying the vector meson-hyperon coupling strength (

\begin{document}$ X_{\omega Y} $\end{document}

) over a wide range, and considering the SU(6) symmetry, we find that a decrease in

\begin{document}$ X_{\omega Y} $\end{document}

results in an increased hyperon population. This leads to a significant softening of the equation of state (EoS) and a reduction in the maximum mass of a neutron star. The models with strong vector repulsion (larger value of

\begin{document}$ X_{\omega Y} $\end{document}

) show a dominance of Λ and

\begin{document}$ \Xi^- $\end{document}

hyperons, with

\begin{document}$ \Xi^0 $\end{document}

appearing only at higher densities. The neutron star properties such as M

\begin{document}$ _{max} $\end{document}

, R

\begin{document}$ _{max} $\end{document}

, and

\begin{document}$ \Lambda_{max} $\end{document}

are strongly affected by the hyperonization for all RMF models. It is observed the canonical star properties like R

\begin{document}$ _{1.4} $\end{document}

and

\begin{document}$ \Lambda_{1.4} $\end{document}

remain largely unaffected to the presence of hyperons in nucleonic EoSs under fixed vector coupling strengths, except when couplings are based on SU(6) symmetry. This behavior can be attributed to the fact that, although hyperons appear in the very centre of a 1.4 M

\begin{document}$ _{\odot} $\end{document}

star, their population fraction is extremely small and therefore has a negligible effect on global stellar properties like R

\begin{document}$ _{1.4} $\end{document}

and

\begin{document}$ \Lambda_{1.4} $\end{document}

. Furthermore, to support a star with observational constraint of M

\begin{document}$ _{max} $\end{document}

\begin{document}$ \ge $\end{document}

2 M

\begin{document}$ _{\odot} $\end{document}

, the vector coupling strength, X

\begin{document}$ _{\omega Y} $\end{document}

must lie in the range 0.8 - 0.9. Our results highlights the critical role of vector coupling strength in governing hyperonization and its impact on neutron star observables. It is found that increasing X

\begin{document}$ _{\omega Y} $\end{document}

improves compliance with the 2 M

\begin{document}$ _{\odot} $\end{document}

mass constraint by suppressing early hyperonization. The critical role of the slope of symmetry energy (L) in regulating the impact of hyperonization on neutron star observables is also studied.

Measurement of the differential and total cross-sections of γ-ray emission induced by 14.1 MeV neutrons for C, Al, Si, Ca, Ti, Cr, and Fe using the tagged neutron method

P.S. Prusachenko, D.N. Grozdanov, N.A. Fedorov, Yu.N. Kopatch, G.V. Pampushik, P.I. Kharlamov, V.R. Skoy, I.N. Ruskov, T.Yu. Tretyakova, A.V. Andreev, C. Hramco, P.G. Filonchik, TANGRA collaboration

Published:

Abstract:
In this work, differential cross sections of

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

-ray emission produced in nuclear reactions induced by 14.1 MeV neutrons are measured for the 4.439 MeV line from carbon, as well as for 10 individual

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

-ray lines from aluminum, 6 from silicon, 8 from calcium, 16 from titanium, 6 from chromium, and 14 from iron. The measurements were conducted using the tagged neutron method with four LaBr₃(Ce) scintillation detectors positioned at angles of 25°, 45°, 60°, and 70° relative to the generator target – sample center axis. A neutron generator capable of producing 16 separate beams of tagged neutrons was employed, which, combined with the detector system, enabled the determination of differential cross-sections for 64 distinct angle values in the range of 17° to 89°. To simplify data visualization, the angular distributions were divided into 5° intervals, with weighted mean values of the angle and differential cross-section calculated for each interval. Corrections for multiple neutron scattering and attenuation,

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

-ray attenuation, and total detection efficiency, computed using GEANT4, were accounted for in the cross-section calculations. Additional measurements were performed to validate the correction calculations. The total

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

-ray emission cross-sections were obtained by approximating the angular distributions with even-order Legendre polynomial expansions up to the 6th degree, followed by integration over the full solid angle. The total systematic error for the obtained data was estimated as 9.1%.

Influence of hexadecapole and hexacontatetrapole deformations and associated orientations on the synthesis of superheavy nuclei

Diksha, Harshit Sharma, Manoj K. Sharma

Published:

Abstract:
The study examines the impact of higher-order deformations up to hexacontatetrapole (

\begin{document}$ \beta_6 $\end{document}

) deformation on the synthesis of superheavy elements (SHN) through heavy-ion induced fusion reactions. The main objective of the study is to examine the impact of modified nuclear shapes, resulting from the collective influence of deformations (up to

\begin{document}$ \beta_6 $\end{document}

), on the barrier characteristics

\begin{document}$ V_B $\end{document}

and

\begin{document}$ R_B $\end{document}

and overall dynamics of nuclear reactions leading to the synthesis of SHN. The analysis takes into account both spherical+deformed and deformed+deformed projectile-target (P-T) combinations, leading to the synthesis of SHN. Furthermore, the analysis also delves into the influence of the sign (

\begin{document}$ \pm $\end{document}

) and magnitude of

\begin{document}$ \beta_6 $\end{document}

on the barrier characteristics and overall reaction dynamics. This analysis examines these effects by utilizing ⁴⁸Ca, ³⁶S and ⁴⁸Ti induced reactions with

\begin{document}$ \beta_6 $\end{document}

-deformed actinide targets. The compact and elongated orientations, influenced by the sign and magnitude of

\begin{document}$ \beta_2 $\end{document}

,

\begin{document}$ \beta_4 $\end{document}

, and

\begin{document}$ \beta_6 $\end{document}

deformations, respectively, introduce further modifications in the reaction dynamics.The capture cross-sections (

\begin{document}$ \sigma_{cap} $\end{document}

), incorporating

\begin{document}$ \beta_6 $\end{document}

along with

\begin{document}$ \beta_2 $\end{document}

and

\begin{document}$ \beta_4 $\end{document}

deformation, result in a better alignment of the calculated cross-sections with the experimental data than the

\begin{document}$ \beta_2\beta_4 $\end{document}

deformations, due to modified barrier characteristics, particularly at near-barrier energies. The findings underscore the importance and impact of incorporating deformations (up to

\begin{document}$ \beta_6 $\end{document}

) and their corresponding orientations to achieve a thorough understanding of the dynamics of heavy-ion induced reactions pertaining to the superheavy mass region.

Probing the Scotogenic Dirac Model with FIMP Dark Matter and ΔN_eff

Shu-Yuan Guo, Man-Yu Zhao

Published:

Abstract:
We study a feebly interacting massive particle realization of the Scotogenic Dirac Model in which the lightest neutral fermion

\begin{document}$ N_1 $\end{document}

serves as a dark matter candidate, produced via the freeze-in or super-WIMP mechanism. The model generates Dirac neutrino masses at one loop, resulting in a rank-2 mass matrix that predicts one nearly massless neutrino. We analyze the DM relic density for various next-to-lightest odd particles (NLOPs), finding that coannihilation effects and enhanced annihilation channels are crucial for achieving the correct thermal freeze-out abundance of the NLOP. We provide a detailed analysis of the model's implications for the effective number of relativistic species,

\begin{document}$ \Delta N_{{\rm{eff}}} $\end{document}

, which receives contributions from both a thermal bath of right-handed neutrinos and non-thermal energy injection due to late NLOP decays. Through an extensive parameter scan, we identify viable parameter space for all NLOP candidates that satisfies constraints from DM relic density, lepton flavor violation, Big Bang Nucleosynthesis, Cosmic Microwave Background, and

\begin{document}$ \Delta N_{{\rm{eff}}} $\end{document}

.

Shadow images of a rotating black hole in Kalb-Ramond gravity surrounded by the thin accretion disk

Ke-Jian He, Chen-Yu Yang, Xiao-Xiong Zeng, Zheng-Xue Chang

Published:

Abstract:
By employing backward ray-tracing techniques, we investigate the shadow image of rotating black holes in Kalb-Ramond gravity. We consider two primary emission models: a spherical source and a thin accretion disk, with the latter assumed to be optically and geometrically thin. The results reveal that enhanced black hole rotation parameter a amplifies the shadow's departure from circular symmetry, whereas spontaneous Lorentz symmetry-breaking parameters

\begin{document}${\cal{G}}$\end{document}

and λ suppress the shadow radius. For accretion disk models, observer inclination angle

\begin{document}$\theta_o$\end{document}

predominantly governs the inner shadow morphology and photon ring brightness asymmetry, while a,

\begin{document}${\cal{G}}$\end{document}

, and λ primarily modulate the inner shadow scale. An increase in

\begin{document}$\theta_o$\end{document}

induces a morphological transition of the inner shadow from a circular to a D-shaped geometry, accompanied by enhanced brightness in a crescent-shaped region on the left side. Meanwhile, increasing the values of a,

\begin{document}${\cal{G}}$\end{document}

, or λ consistently reduces the shadow dimensions. Furthermore, higher inclination angles

\begin{document}$\theta_o$\end{document}

further enhance spectral differentiation, that is, low inclination angles exhibit exclusively redshifted emission, whereas those at high inclination angles produce blueshifted components in both direct and lensed images. These characteristic signatures provide observational discriminators between rotating Kalb-Ramond black holes and alternative spacetime.

Gravitational waves from equatorially eccentric extreme mass ratio inspirals around swirling-Kerr black holes

Yuhang Gu, Songbai Chen, Jiliang Jing

Published:

Abstract:
The swirling-Kerr black hole is a novel solution of vacuum general relativity and has an extra swirling parameter characterizing the rotation of spacetime background. We have studied the gravitational waves generated by extreme mass ratio inspirals (EMRIs) along eccentric orbits on equatorial plane in this novel swirling spacetime. Our findings indicate that this swirling parameter leads to a delayed phase shift in the gravitational waveforms. Furthermore, we have investigated effects of the swirling parameter on the potential issue of waveform confusion caused by the orbital eccentricity and semi-latus rectum parameters. As the swirling parameter increases, the relative variations in the eccentricity increase, while the variations in the semi-latus rectum decrease rapidly. These trends of the changes related to the orbital eccentricity and the semi-latus rectum with the swirling parameter resemble those observed with the MOG parameter in the Scalar-Tensor-Vector-Gravity (STVG) theory, but with different rates of change. Furthermore, our results also reveal that effects of the background swirling parameter on the relative variations in the eccentricity and the semi-latus rectum are distinctly different from those of the black hole spin parameter. These results provide deeper insights into the properties of EMRI gravitational waves and the background's swirling.

Bayesian-optimized CatBoost for Ground-State Nuclear Charge-Radius Prediction

Mudassar Ahmed, Abdul Kabir, Jameel-Un Nabi, Laiba Hamid, Manzoor Ahmad

Published:

Abstract:
Understanding nuclear shape, behavior, and stability, as well as improving nuclear models, depends on the precise determination of ground-state nuclear charge radii. Existing experimental techniques are limited to very narrow regions of the nuclear chart; however, theoretical models, including relativistic Hartree-Bogoliubov (RHB) and Hartree-Fock-Bogoliubov (HFB), predict broad trends of nuclear properties but miss fine isotopic features such as odd-even staggering effects and shell-closure kinks. High computational time and cost are another obstacle to theoretical approaches. Although machine-learning algorithms have made significant progress in predicting charge radii, they are still hindered by a lack of balanced data and characteristics, primarily centered around

\begin{document}$ A\ge40 $\end{document}

and

\begin{document}$ Z\ge20 $\end{document}

. In the present study, we present the first application of CatBoost regression to compute nuclear charge radii. We integrate two experimental datasets with RHB-calculated point-coupling interaction (PC-X) theoretical features and extend our study range to

\begin{document}$ A\ge17 $\end{document}

,

\begin{document}$ Z\ge8 $\end{document}

. We find the best hyperparameters using Optuna’s Tree-structured Parzen Estimator (TPE) sampler with 10-fold cross-validation (CV), achieving a CV root-mean-square error (RMSE) of 0.0106 fm and hold-out RMSE of 0.0102 fm, with only three features i.e. neutron number (N), proton number (Z), and RHB theoretical binding energy (BE), outperforming nine other ML models, including random forest (RF), quantile RF (QRF), Cubist, Gaussian process regression with polynomial kernel (GPPK), multivariate adaptive regression splines (MARS), SVR, ANN, and convolutional neural network (CNN) and the Brussels-Skyrme-on-a-grid 3 (BSkG3) model. SHapley Additive exPlanations (SHAP) analysis confirms the highest global influence of BE in the model's predictions, followed by proton number and neutron number, and the model can accurately reproduce the

\begin{document}$ N=50 $\end{document}

kink and odd-even staggering effects in krypton and strontium chains. These results establish CatBoost as a robust and very promising model for charge-radius prediction and beyond, with the potential to impact r-process modeling and future theoretical development.

Investigation of Resonances in the Σ(1/2^-) System Based on the Chiral Quark Model

Yu Yao, Xuejie Liu, Xiaoyun Chen, Yuheng Wu, Jialun Ping, Yue Tan, Qi Huang

Published:

Abstract:
In this work, we investigate the resonance structures in the

\begin{document}$ \Sigma(1/2^-) $\end{document}

system from both three-quark and five-quark perspectives within the framework of the chiral quark model. An accurate few-body computational approach, the Gaussian Expansion Method, is employed to construct the orbital wave functions of multiquark states. To reduce the model dependence on parameters, we fit two sets of parameters to check the stability of the results. The calculations show that our results remain stable despite changes in the parameters. In the three-quark calculations, two

\begin{document}$ \Sigma(1/2^-) $\end{document}

states are obtained with energies around 1.8 GeV, which are good candidates for the experimentally observed

\begin{document}$ \Sigma(1750) $\end{document}

and

\begin{document}$ \Sigma(1900) $\end{document}

. In the five-quark configuration, several stable resonance states are identified, including

\begin{document}$ \Sigma \pi $\end{document}

,

\begin{document}$ N \bar{K} $\end{document}

, and

\begin{document}$ N \bar{K}^{*} $\end{document}

. These resonance states survive the channel-coupling calculations under the complex-scaling framework and manifest as stable structures. Our results support the existence of a two-pole structure for the

\begin{document}$ \Sigma(1/2^-) $\end{document}

system, predominantly composed of

\begin{document}$ \Sigma \pi $\end{document}

and

\begin{document}$ N \bar{K} $\end{document}

configurations, analogous to the well-known

\begin{document}$ \Lambda(1380) $\end{document}

-

\begin{document}$ \Lambda(1405) $\end{document}

(

\begin{document}$ \Sigma \pi $\end{document}

-

\begin{document}$ N \bar{K} $\end{document}

) system. On the other hand, although the energy of the

\begin{document}$ N \bar{K}^{*} $\end{document}

configuration is close to that of

\begin{document}$ \Sigma(1750) $\end{document}

and

\begin{document}$ \Sigma(1900) $\end{document}

, the obtained width is not consistent with the experimental values. This suggests that the

\begin{document}$ N \bar{K}^{*} $\end{document}

state needs to mix with three-quark components to better explain the experimental

\begin{document}$ \Sigma(1750) $\end{document}

and

\begin{document}$ \Sigma(1900) $\end{document}

states. According to our decay width calculations, the predicted two resonance states are primarily composed of

\begin{document}$ \Sigma \pi $\end{document}

and

\begin{document}$ N \bar{K} $\end{document}

, with their main decay channel being

\begin{document}$ \Lambda \pi $\end{document}

. Therefore, we encourage experimental groups to search for the predicted two-pole structure of the

\begin{document}$ \Sigma(1/2^-) $\end{document}

system in the invariant mass spectrum of

\begin{document}$ \Lambda \pi $\end{document}

.

Nuclear matter properties from chiral-scale effective theory including a dilatonic scalar meson

Lu-Qi Zhang, Yao Ma, Yong-Liang Ma

Published:

Abstract:
Chiral effective theory has become a powerful tool for studying the low-energy properties of QCD. In this work, we apply an extended chiral effective theory—chiral-scale effective theory—including a dilatonic scalar meson to study nuclear matter and find that the properties around saturation density can be well reproduced. Compared to Walecka-type models in nuclear matter studies, our approach improves the behavior of symmetry energy in describing empirical data without introducing additional isovector scalar meson δ to make it soft at intermediate densities. Moreover, the predicted neutron star mass-radius relations fall within the constraints of GW170817, PSR J0740+6620, and PSR J0030+0451, while the maximum mass of neutron star mass can reach

\begin{document}$\gtrsim 2.5M_{\odot}$\end{document}

with a pure hadronic phase. Additionally, we find that symmetry patterns of the effective theory significantly impact neutron star structures. We believe that introducing this type of theory into nuclear matter studies can contribute to a more comprehensive understanding of QCD, nuclear matter, and compact astrophysical objects.

Uncertainty analysis of the nuclear liquid drop model

Xiao-Yu Xu, X. Q. Qi, L. Deng, A. X. Chen, H. K. Wang, Y. B. Qian

Published: , doi: 10.1088/1674-1137/ae1444

Abstract:
This study made a statistical analysis on the correlation and uncertainty of parameters in the classical liquid drop mass formula (namely BW3 type) via the regression way, along with the theoretical impact of error propagation. Within the improved BW3 formula, the total deviation between evaluation and experiment can be reduced to 1.66 MeV, involving the reduction from 2.89 (2.42) MeV to 1.92 (1.89) MeV in the proton(neutron)-dripline region. The ridge regression validation verified this total deviation as the optimal point in the present mass model. Through trend coefficients and Pearson linear-correlation analysis, obvious collinearity was identified between volume, surface, Coulomb and curvature terms, with notable correlation among high-order symmetry energy and surface symmetry terms. The theoretical derivation of the distribution in the binding energy error was then achieved through error propagation analysis. Across the nuclide chart, the error uncertainty of mass predictions varies from 1.996 keV to 124.469 keV, demonstrating a convex trend of the initial decrease of evaluation error following by the increasing versus the neutron number.

Nuclear Medium Effects for Modifying Tensor Interaction

Tao-Feng Wang, Zi-Ming Li, Xiao-Ting Yang, Min-Liang Liu, Jian-Song Wang, Yan-Yun Yang, Zhi-Yu Sun, Cheng-Jian Lin, Qing-Hua He, Zhen Bai, Fang-Fang Duan, Zhi-Hao Gao, Song Guo, Yue Hu, Wei Jiang, F. Kobayashi, Chen-Gui Lu, Jun-Bing Ma, Peng Ma, Jian-Guo Wang, Xiang-Lun Wei, He-Run Yang, Yong-Jin Yao, Jun-Wei Zhang

Published: , doi: 10.1088/1674-1137/ae167d

Abstract:
The cross section for the

\begin{document}$ J^{\pi}(T)=3^{+}(0) $\end{document}

state was measured to be enhanced in an isolated

\begin{document}$ ^{6} $\end{document}

Li nucleus compared to the same reduced state in a

\begin{document}$ ^{6} $\end{document}

Li cluster. This difference demonstrates a nuclear medium modification of the tensor force, which is sensitively probed by the

\begin{document}$ T=0 $\end{document}

channel. In contrast, the

\begin{document}$ J^{\pi}(T)=0^{+}(1) $\end{document}

state (

\begin{document}$ T=1 $\end{document}

) was found to have approximately equal excitation strength in both

\begin{document}$ ^{6} $\end{document}

Li systems. We interpret this tensor force modification as a consequence of density saturation within a many-body interaction framework.

Contributions of ρ(770,1450)→ωπ for the Cabibbo-favored D→hωπ decays

Wen-Fei Wang, Jiao-Yuan Xu, Si-Hong Zhou, Pan-Pan Shi

Published: , doi: 10.1088/1674-1137/ae120b

Abstract:
Recently, the BESIII Collaboration has observed the three-body decays

\begin{document}$ D_s^+\to \eta \omega\pi^+ $\end{document}

,

\begin{document}$ D^+\to K^0_S\pi^+\omega $\end{document}

and

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

. In this work, we investigate the contributions of the subprocesses

\begin{document}$ \rho^+\to \omega\pi^+ $\end{document}

in these Cabibbo-favored decays

\begin{document}$ D \to h\omega\pi $\end{document}

, with

\begin{document}$ \rho^+= \{\rho(770)^+, \rho(1450)^+, \rho(770)^+\&\rho(1450)^+\} $\end{document}

and

\begin{document}$ h=\{ \eta, K^0_S, K^-\} $\end{document}

, by introducing these subprocesses into the decay amplitudes of relevant decay processes via the vector form factor

\begin{document}$ F_{\omega\pi} $\end{document}

which has measured in the related τ and

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

processes; we provide the first theoretical predictions for the branching fractions of the quasi-two-body decays

\begin{document}$ D_s^+\to\eta[\rho^+\to]\omega\pi^+ $\end{document}

,

\begin{document}$ D^+\to K^0_S[\rho^+\to]\omega\pi^+ $\end{document}

and

\begin{document}$ D^0\to K^-[\rho^+\to]\omega\pi^+ $\end{document}

. Our findings reveal that the contributions from the subprocess

\begin{document}$ \rho(770)^+\to\omega\pi^+ $\end{document}

are significant in these observed three-body decays

\begin{document}$ D_s^+\to\eta \omega\pi^+ $\end{document}

,

\begin{document}$ D^+\to K^0_S \omega\pi^+ $\end{document}

and

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

, notwithstanding the contributions originating from the Breit-Wigner tail effect of

\begin{document}$ \rho(770)^+ $\end{document}

. The numerical results of this study suggest that the dominant resonance contributions for the three-body decays

\begin{document}$ D_s^+\to\eta \omega\pi^+ $\end{document}

and

\begin{document}$ D^+\to K^0_S \omega\pi^+ $\end{document}

are originated from the P-wave intermediate states

\begin{document}$ \rho(770)^+ $\end{document}

,

\begin{document}$ \rho(1450)^+ $\end{document}

and their interference effects.

Study of P and CP symmetries in ${ \boldsymbol\Xi^{\bf +}_{\boldsymbol c}\rightarrow \boldsymbol\Xi^-\boldsymbol\pi^+\boldsymbol\pi^+ }$ at electron-positron collider

Yunlu Wang, Yunlong Xiao, Pengcheng Hong, Ronggang Ping

Published:

Abstract:
Symmetry studies represent one of the most promising frontiers in particle physics research. This investigation focuses on exploring P and

\begin{document}$ CP $\end{document}

symmetries in the charm system through the measurement of asymmetry decay parameters in the three-body decay of

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

. Incorporating electron and positron beam polarization effects and utilizing the helicity formalism, we characterize the decay of

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

and its secondary hyperons through asymmetry decay parameters. The complete angular distribution formula for these decays has been systematically derived. Our study evaluates the sensitivity of the asymmetry parameters for the

\begin{document}$ \Xi_c^{+} \to \Xi^{-}\pi^{+}\pi^{+} $\end{document}

decay channel under various data sample sizes and beam polarization scenarios. These findings establish a robust theoretical framework for future experimental studies at the STCF, providing valuable insights for symmetry investigations in the charm sector.

Study of color-flavor locked quark stars in ${\boldsymbol f(R,L_{m},T)}$ gravity using observational data

Jie Li, Yi Zhu, Bo Yang, Wenbin Li

Published:

Abstract:
We investigate the physical properties of quark stars within the framework of

\begin{document}$f(R,L_{m},T)$\end{document}

gravity. The quark matter inside these stars is modeled as de-confined quarks and described by a color-flavor-locked equation of state. Using this equation of state, we numerically solve the modified Tolman-Oppenheimer-Volkoff (TOV) equation to obtain the mass and radius of quark stars. We analyze key properties of the quark star such as the dynamical stability, compactness, and gravitational redshift. The results show that the modified gravitational theory has a significant impact on the properties of quark stars and consistently explains the observational data of massive pulsars.

Studying the proton rms radii of Li and B isotope through elastic scattering

Ling-Hao Wang, Fang-Fang Duan, Kang Wang, Guo Yang, Xing-quan Liu, Yan-Yun Yang

Published: , doi: 10.1088/1674-1137/ae1183

Abstract:
The root mean square (rms) nuclear proton radii of ^6,7,8Li and ^10,11B projectiles are systematically investigated through the analyses of elastic scattering data from target nuclei with mass numbers ranging from 40 to 209 at incident energies above the Coulomb barriers. The analyses employs a consistent single-folding model potential based on the Bruyères Jeukenne-Lejeune-Mahaux (JLMB) nucleon-nucleus interaction model, incorporating 112 sets of elastic scattering data to derive the projectile nuclear radii. This approach yields individual radii for each set, from which the mean rms proton radius is extracted as a characteristic parameter for the projectile nuclei. The rms proton radii of ^6,7Li and ^10,11B nuclei obtained from optical model fits demonstrate good agreement with both experimental measurements and existing theoretical predictions. Notably, a significantly smaller nuclear radius of ⁸Li is observed compared to values derived from intermediate-energy proton elastic scattering cross-section measurements, which may be attributed to additional dynamical effects specific to the ⁸Li projectile.

The properties of the S-wave D_sD_s bound state

Jing-Juan Qi, Zhen-Yang Wang, Zhu-Feng Zhang, Xin-Heng Guo

Published: , doi: 10.1088/1674-1137/ae1195

Abstract:
In this work, we investigate possible bound states in the

\begin{document}$ D_s\bar{D}_s $\end{document}

system using the Bethe-Salpeter formalism within both the ladder and instantaneous approximations. By numerically solving the Bethe-Salpeter equation with a kernel that incorporates contributions from ϕ and

\begin{document}$ J/\psi $\end{document}

meson exchanges, we confirm the existence of a loosely bound state. Furthermore, we explore the partial decay widths of the

\begin{document}$ D_s\bar{D}_s $\end{document}

bound state into the

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

,

\begin{document}$ \eta_c\eta $\end{document}

, and

\begin{document}$ J/\psi\omega $\end{document}

channels, and observe that these widths are sensitive to the model parameter α. Notably, we find the dominant decay channel for the

\begin{document}$ D_s\bar{D}_s $\end{document}

bound state to be

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

.

Neutron stars and Pulsar timing arrays as Axion giant gyroscopes

Jinneng Luo, Yiming Liu, Sichun Sun

Published: , doi: 10.1088/1674-1137/ae1189

Abstract:
We consider the three-dimensional rotating motions of neutron stars blown by the “axion wind”. Neutron star precession and spin can change from the magnetic moment coupling to the oscillating axion background field, in analogy to the gyroscope motions with a driving force and the laboratory Nuclear Magnetic Resonance (NMR) detections of the axion. This effect modulates the pulse arrival time of pulsar timing arrays through changes in the pulsars' periods. It appears as a signal in the timing residual and two-point correlation function of recent Nanograv and PPTA data. The current measurement of PTAs can thus cast constraints on the axion-nucleon coupling as

\begin{document}$ g_\text{ann} \sim 10^{-12}\text{GeV}^{-1} $\end{document}

with axion mass around

\begin{document}$ 10^{-23} $\end{document}

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

.

Proton separation energy predictions for proton-rich nuclei with the radial basis function approach and mirror symmetry

Tao Li, Min Liu, Ning Wang

Published:

Abstract:
Mirror symmetry is combined with the radial basis function (RBF) approach to improve the prediction accuracy of proton separation energy. Compared with the traditional RBF approach, the RBF approach combine with mirror symmetry (RBFms) mainly involves training the residual of the one/two-proton separation energy deviation of the nucleus and the one/two-neutron separation energy deviation of its mirror nucleus. The KTUY model combined with the RBFms approach yields an root-mean-square (rms) deviation of 0.113 MeV for one-proton separation energies of 143 nuclei, while the DZ31 model combined with the RBFms approach achieves rms deviation of 0.089 MeV for two-proton separation energies of 115 nuclei. In the region where the proton number

\begin{document}$ Z=14-38 $\end{document}

, the proton drip line and two-proton decay candidate nucleus are predicted by DZ31, FRDM12, KTUY, and WS4 models combine with the RBFms approach.

Tensor formalism for the partial wave analysis of reactions with resonances decaying into four pseudoscalar mesons

M.A. Matveev, A.T. Sitnikov, A.V. Sarantsev

Published:

Abstract:
We construct a formalism which describes the resonances decaying into four pseudoscalar meson final states. This method is fully covariant and can be directly applied for the partial-wave analysis of high statistical data. Two topologies of the process are considered: two intermediate resonances each decaying into two final mesons and cascade decay via three meson intermediate states. In particular, we consider the production of such states in the central collision reactions and in radiative

\begin{document}$J/\Psi$\end{document}

decay.

Energy Dependence of Elliptic Flow Ratio v₂^PP/v₂^RP in Heavy-ion Collisions Using the AMPT Model

Shaowei Lan, Qiuhua Liu, Yong Li, Shusu Shi

Published:

Abstract:
We present a systematic study of the elliptic flow

\begin{document}$ v_2 $\end{document}

relative to the participant plane (PP) and reaction plane (RP) in Au+Au collisions at

\begin{document}$ \sqrt{s_{NN}} = 7.7 $\end{document}

–200 GeV using the AMPT model with the string melting version. The ratio

\begin{document}$ v_{2}^{\text{PP}} $\end{document}

/

\begin{document}$ v_{2}^{\text{RP}} $\end{document}

is investigated under different hadronic cascade times (0.6 fm/c, 10 fm/c, and the maximum evolution time) and across various collision centralities. The results show that, at a fixed collision energy, the ratio exhibits negligible sensitivity to the duration of the hadronic rescattering stage, indicating that hadronic interactions have little effect on the relative difference generated by initial-state fluctuations. However, a strong energy dependence is observed, the ratio increases with beam energy and saturates above

\begin{document}$ \sqrt{s_{NN}} \approx 62.4 $\end{document}

GeV, a trend that persists across all centralities. These findings highlight the dominant role of the partonic phase in converting initial-state geometry fluctuations into final-state momentum anisotropy. Conversely, at lower energies, the reduced partonic interaction strength limits this conversion efficiency, weakening the system’s ability to preserve the initial geometric information. Our results suggest that the conversion of initial geometric fluctuations into final momentum anisotropy requires sufficient partonic interactions.

Searching Quantum Entanglement in pp → ZZ process

Alim Ruzi, Youpeng Wu, Ran Ding, Qiang Li

Published:

Abstract:
Recent studies have shown that observing entangled particle states at a particle collider like Large Hadron Collider (LHC) and testing violation of Bell inequality in them can open up new research area for high energy physics study. We examine the presence of quantum entanglement in the

\begin{document}$ pp\to ZZ\to 4\ell $\end{document}

process at leading order. We apply generally recognized method, quantum state tomography, to reconstruct spin density matrix of the joint ZZ system, through which all the relevant observables can be obtained. The angular distribution of the final leptons are obtained from simulated events using Monte-Carlo program, which is used to reconstruct spin density matrix. Non-zero value of the lower bound of the concurrence is measured with simulated data. The numerical analysis shows that with the luminosity corresponding to LHC Run 2+3, entanglement can be probed at 2

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

level and up to 3.75

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

level for High-Luminosity LHC data (3ab^-1), revealing the possibility of finding quantum entanglement in real collider experiment.

Predictions for the isospin-violating decays of ${{\boldsymbol B}_{\boldsymbol c}({\boldsymbol{1P}})^{\bf +}\bf\to{\boldsymbol B}_{\boldsymbol c}^{({\bf *})+}\boldsymbol\pi^{\bf 0}}$

Jun Wang, Qiang Zhao

Published:

Abstract:
In this work we study the isospin-violating decays of

\begin{document}$ B_{c}(1P)^{+}\to B_{c}^{(*)+}\pi^{0} $\end{document}

, which may provide additional information for the determination of the properties of the first orbital excitation states of

\begin{document}$ B_{c}(1P)^{+} $\end{document}

. By assuming a dual relation between the U(1) anomaly soft-gluon coupling for

\begin{document}$ B_{c}(1P)^{+}\to B_{c}^{(*)+}\pi^{0} $\end{document}

and the intermediate meson loop transitions, we can quantify the isospin-violating decay effects for these four P-wave states. We find that the partial decay width of

\begin{document}$ B_{c0}^{*+}\to B_{c}^{+}\pi^{0} $\end{document}

is about three orders of magnitude larger than that for

\begin{document}$ B_{c2}^{*+}\to B_{c}^{+}\pi^{0} $\end{document}

. It implies that

\begin{document}$ B_{c0}^{*+} $\end{document}

can be established in the

\begin{document}$ B_{c}^{+}\pi^{0} $\end{document}

decay channel as a single state. Meanwhile, the two axial-vector states

\begin{document}$ B_{c1}^{+}/B_{c1}'^{+} $\end{document}

can be possibly identified in

\begin{document}$ B_{c1}^{+}/B_{c1}'^{+}\to B_{c}^{*+}\pi^{0} $\end{document}

with comparable strengths. Although these isospin-violating decays turn out to be small, the theoretical predictions should be useful for guiding future experimental efforts.

Resolving the W boson Mass in the Lepton Specific Two Higgs Doublet Model

Ali Çiçi, Hüseyin Dağ

Published:

Abstract:
In 2022, the CDF Collaboration reported the W-boson mass,

\begin{document}$ M_W=80.4335\pm0.0094\; \text{GeV} $\end{document}

, which deviates from the Standard Model (SM) prediction,

\begin{document}$ M_W^{\rm SM}=80.357\pm0.006\; \text{GeV} $\end{document}

, by about

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

. By contrast, the CMS Collaboration obtained

\begin{document}$ M_W=80.3602\pm0.0099\; \text{GeV} $\end{document}

, very close to the SM global electroweak fit value of

\begin{document}$ \sim80.357\; \text{GeV} $\end{document}

. Motivated by this situation, we reassess the W-boson mass within the Lepton-Specific Two Higgs Doublet Model (LS-2HDM). We perform random scans (generated with SARAH 4.13.0 and evaluated with SPheno 4.0.3) and confront the results with up-to-date theoretical and experimental constraints. The scan enforces vacuum stability, perturbative unitarity, and perturbativity; electroweak precision observables via the oblique parameters

\begin{document}$ (S,T,U) $\end{document}

; LEP bounds on

\begin{document}$ H^\pm $\end{document}

; rare B-meson decays; lepton flavor universality (LFU) in Z and τ decays; and LHC 13 TeV searches for additional Higgs bosons. Viable points are further tested with HiggsTools (HiggsSignals + HiggsBounds). In the LS-2HDM, if

\begin{document}$ h_1 $\end{document}

is the SM-like Higgs at

\begin{document}$ m_{h_1}\simeq125 $\end{document}

GeV with

\begin{document}$ |\cos(\beta-\alpha)|\lesssim0.06 $\end{document}

,

\begin{document}$ 17\lesssim\tan\beta\lesssim39 $\end{document}

,

\begin{document}$ 144\lesssim m_{h_2}\lesssim414 $\end{document}

GeV, and

\begin{document}$ 435\lesssim m_{A,H^{\pm}}\lesssim685 $\end{document}

GeV, the model reproduces the 2024 CMS W-boson mass within

\begin{document}$ 3\sigma $\end{document}

. Solutions near the 2022 CDF value,

\begin{document}$ M_W=80.4335\pm0.0094\; \text{GeV} $\end{document}

, survive; however, after applying all constraints, including HiggsTools, they approach it at best within

\begin{document}$ \lesssim2\sigma $\end{document}

. Our findings emphasize that the LS-2HDM favors the CMS results consistently with the current experimental results. On the other hand, while one can accommodate also the CDF results in this model theoretically, up-to-date electroweak precision bounds on the oblique parameters

\begin{document}$ (S,T,U) $\end{document}

together with the SM-like Higgs and LFU constraints exclude these solutions and our results for

\begin{document}$ W- $\end{document}

boson mass can be only as close as about

\begin{document}$ 2\sigma $\end{document}

to the CDF results.

Resonant states in the Schrödinger equation solved by the Green's function method

Wentao Zeng, Zehao Lin, Yiran Wang, Shuangquan Zhang, Jinniu Hu, Ying Zhang

Published:

Abstract:
The Schrödinger equation with Woods-Saxon type potentials is solved by the Green's function (GF) method. Taking the nucleus

\begin{document}$^{40}\mathrm{Ca}$\end{document}

as an example, we show that the GF results for both bound and resonant single-neutron states are consistent with those obtained by the shooting and scattering matrix methods respectively. Explicitly, three different recipes (GFI, GFII, and GFIII) are used to figure out the energies and widths of resonant states. The GFI method directly reads the resonant energy and width from the calculated density of states after removing the contributions of free particles. The GFII method identifies the resonant states by examining the flip of the density of states, while the GFIII method searches for the resonant states as poles of the modulus of GF on the complex energy plane. It is found that the GFI method is effective for the resonant states with narrow widths. For the resonant states with broad widths, the GFII and GFIII methods are more accurate and effective. We also verified that the energies, widths, and density distributions of resonant states obtained by the GF method exhibit a rather weak dependence on the box size.

Use of SU(3) flavor projection operators to construct baryon-meson scattering amplitudes in the 1/N_c expansion

Víctor Miguel Banda Guzmán, Rubén Flores-Mendieta, Johann Hernández

Published:

Abstract:
An SU(3) flavor projection operator technique is implemented to construct the baryon-meson scattering amplitude in the framework of the

\begin{document}$1/N_c$\end{document}

expansion of QCD, where

\begin{document}$N_c$\end{document}

is the number of color charges. The operator technique is implemented to evaluate not only the lowest-order scattering amplitude but also effects coming from first-order perturbative SU(3) flavor symmetry breaking and strong isospin breaking. The most general expression is obtained by accounting for explicitly the effects of the decuplet-octet baryon mass difference. At order

\begin{document}${\cal{O}}(1/N_c^2)$\end{document}

, a large number of unknown operator coefficients appear, so there is little additional predictive power unless leading and subleading terms are retained. Although the resultant expression is general enough that it can be applied to any incoming and outgoing baryons and pseudo scalar mesons, provided that the Gell-Mann--Nishijima scheme is respected, results for

\begin{document}$N\pi\to N\pi$\end{document}

scattering processes are explicitly dealt with.

Axisymmetric generalization of zero-scalar-curvature solutions from the Schwarzschild metric via Newman-Janis algorithm

Chen Lan, Zi-Xiao Liu, Yan-Gang Miao

Published:

Abstract:
We address a specific issue of the Newman-Janis algorithm: How to determine the general form of the complex transformation for the Schwarzschild metric and ensure that the resulting axisymmetric metric satisfies the zero-scalar-curvature condition,

\begin{document}$ R=0 $\end{document}

. In this context, the zero-scalar-curvature condition acts as a constraint. Owing to this condition, we refer to the class of black holes as the "Newman-Janis class of Schwarzschild black holes" in order to emphasize Newman-Janis algorithm's potential as a classification tool for axisymmetric black holes. The general complex transformation we derive not only generates the Kerr, Taub-NUT, and Kerr-Taub-NUT black holes under specific choices of parameters but also suggests the existence of additional axisymmetric black holes. Our findings open an alternative avenue using the Newman-Janis algorithm for the construction of new axisymmetric black holes.

Tilted-axis-cranking covariant density functional theory for the high-spin spectroscopy in ⁶⁹Ga

Y. P. Wang, Y. K. Wang, P. W. Zhao

Published: , doi: 10.1088/1674-1137/ae07b8

Abstract:
The tilted-axis-cranking covariant density functional theory is applied to investigate the three newly-observed positive-parity bands SI, SII, and SIII in ⁶⁹Ga. The energy spectra and angular momenta are calculated and good agreements with the experimental data are realized. For the band SI, pairing correlations play a crucial role for the states with spin

\begin{document}$I\leq 23/2\hbar$\end{document}

. The bands SII and SIII are suggested to be signature partner bands with positive and negative signatures, respectively. By analyzing the angular momentum alignments, it is revealed that the

\begin{document}$g_{9/2}$\end{document}

protons and neutrons play an important role in the collective structures of ⁶⁹Ga. The transition probabilities

\begin{document}$B(E2)$\end{document}

for these bands are predicted, awaiting further experimental verification.

UrQMD Simulations of Higher-order Cumulants in Au+Au Collisions at High Baryon Density

Xin Zhang, Yu Zhang, Xiaofeng Luo, Nu Xu

Published: , doi: 10.1088/1674-1137/ae0995

Abstract:
High moments of conserved quantities such as net-baryon, net-electric charge, and net-strangeness in heavy-ion collisions are sensitive to fluctuations caused by the QCD critical point (CP). The event-by-event analysis of high moments of the conserved charges has been widely used in experiments to search for the CP, especially in the RHIC-STAR experiment. In order to establish a dynamical non-critical base line, especially at the high baryon density region, we have performed a systematic analysis of the proton multiplicity distributions from Au+Au collisions at

\begin{document}$ 3 \leq \sqrt{s_{NN}} \leq 9.2 $\end{document}

GeV collisions. The results on beam energy, centrality and rapidity width dependence of proton (factorial) cumulants, up to the

\begin{document}$ 4^{th} $\end{document}

order, are extracted from the calculations of the hadronic transport model UrQMD. In addition, the effects of initial volume fluctuation is also discussed. These results will be important when we do physics analysis the RHIC beam energy scan (BES) data, especially for the fixed-target data and experimental data from future CBM experiment at FAIR.

Rephasing invariant formulae for CP phases in general parameterizations of flavor mixing matrix and exact sum rules with unitarity triangles

Published:

Abstract:
In this letter, we present rephasing invariant formulae

\begin{document}$ \delta^{(\alpha i)} = \arg [{ V_{\alpha 1} V_{\alpha 2} V_{\alpha 3} V_{1i} V_{2i} V_{3i} / V_{\alpha i }^{3} \det V }] $\end{document}

for CP phases

\begin{document}$ \delta^{(\alpha i)} $\end{document}

associated with nine Euler-angle-like parameterizations of a flavor mixing matrix. Here, α and i denote the row and column carrying the trivial phases in a given parameterization. Furthermore, we show that the phases

\begin{document}$ \delta^{(\alpha i)} $\end{document}

and the nine angles

\begin{document}$ \Phi_{\alpha i} $\end{document}

of unitarity triangles satisfy compact sum rules

\begin{document}$ \delta^{(\alpha, i+2)} - \delta^{(\alpha, i+1)} = \Phi_{\alpha+1, i} - \Phi_{\alpha+2, i} $\end{document}

and

\begin{document}$ \delta^{(\alpha+1, i)} - \delta^{(\alpha+2, i)} = \Phi_{\alpha, i+2} - \Phi_{\alpha, i+1} $\end{document}

where all indices are taken cyclically modulo three. These relations are natural generalizations of the previous result

\begin{document}$ \delta_{\mathrm{PDG}}+\delta_{\mathrm{KM}}=\pi-\alpha+\gamma. $\end{document}

Ground-state properties of finite nuclei in relativistic Hartree-Bogoliubov theory with an improved quark mass density-dependent model

Renli Xu, Chen Wu, Jian Liu, Bin Hong, Jie Peng, Xiong Li, Ruxian Zhu, Zhizhen Zhao, Zhongzhou Ren

Published:

Abstract:
A relativistic Hartree-Bogoliubov (RHB) model based on quark-meson coupling is developed, with a new parametrization derived from experimental observables. Using this model, we systematically investigate the ground-state properties of even-even nuclei spanning

\begin{document}$ 8\leq Z\leq118 $\end{document}

, including binding energies, quadrupole deformations, root-mean-square (rms) charge radii, two-nucleon separation energies, two-nucleon shell gaps, and α-decay energies. Comparisons with available experimental data demonstrate that this subnucleon-based RHB model reliably describes the ground-state properties of finite nuclei.

Evaluation of the moments of inertia of forced split fragments for nuclei ²³²Th (n,f) and ²³⁸U (n,f)

xxx xx

Published:

Abstract:
This study develops an innovative theoretical framework that integrates macroscopic liquid-drop model with microscopic superfluid theory to calculate moments of inertia for fission fragments, extending our previous spontaneous fission approach to include neutron-induced threshold fission of

\begin{document}$ {}^{232}Th\left( {n,f} \right) $\end{document}

and

\begin{document}$ {}^{238}{\text{U}}\left( {n,f} \right) $\end{document}

. The model provides a comprehensive description of fission dynamics by simultaneously accounting for collective vibrational modes (bending and wriggling) and their influence on spin distributions, while systematically investigating the deformation dependence of moments of inertia. Our calculations demonstrate good agreement with experimental data, validating the model's reliability for both fundamental nuclear fission studies and practical applications in reactor physics. The unified treatment of macroscopic and microscopic effects offers new insights into fission mechanisms and enables accurate predictions of fragment characteristics across the entire mass range. These results provide a solid basis for future studies of exotic fission processes and advanced applications in nuclear energy. The methodological advances presented here open new possibilities for theoretical studies of various heavy-ion reactions and fission phenomena in superheavy nuclei.

Globally Stable Dark Energy in F(R) Gravity

Hua Chen

Published:

Abstract:

\begin{document}$F(R)$\end{document}

models for dark energy generally exhibit a weak curvature singularity, which can be cured by adding an

\begin{document}$R^2$\end{document}

term. This correction allows for a unified description of primordial and late-time accelerated expansions. However, most existing models struggle to achieve this, as they become unstable over certain negative ranges of the Ricci scalar, where either the first or second derivative of

\begin{document}$F(R)$\end{document}

turns negative. These instabilities may disrupt the post-inflationary evolution when the Ricci scalar oscillates about the vacuum state after the

\begin{document}$R^2$\end{document}

inflation. In this work, we introduce a new model-building to guarantee global stability, i.e., the first and second derivatives are positive for all real Ricci scalars. By extending the idea from Appleby and Battye, we demonstrate that viable models can be constructed by imposing a positive, bounded first derivative of

\begin{document}$F(R)$\end{document}

with a sigmoid shape. As examples, we first reformulate and generalize the original Appleby-Battye model. Then, we propose a new dark energy model, which successfully explains the acceleration of cosmic expansion and passes local gravity tests.

Solving bound-state equations for scalar and hybrid QCD in two-dimensional spacetime

Xiaolin Li, Yu Jia, Ying Li, Zhewen Mo

Published:

Abstract:
We investigate the bound-state equations in two-dimensional QCD in the

\begin{document}$ N_c\to \infty $\end{document}

limit. We consider two types of hadrons, an exotic "meson" (which is composed of a bosonic quark and a bosonic anti-quark), and an exotic "baryon" (composed of a fermionic quark and a bosonic antiquark). Using the Hamiltonian operator approach, we derive the corresponding bound-state equations for both types of hadrons from the perspectives of the light-front quantization and equal-time quantization, and confirm the known results. We also present a novel diagrammatic derivation for the exotic "meson" bound-state equation in the equal-time quantization. The bound-state equation for the exotic baryons in the equal-time quantization in two-dimensional QCD is new. We also numerically solve various bound-state equations, obtain the hadron spectrum and the bound-state wave functions of the lowest-lying states. We explicitly demonstrate the pattern that as the hadron is boosted to the infinite-momentum frame, the forward-moving bound-state wave function approaches the corresponding light-front wave function.

Particle-number conserving analysis of the πd_5/2 band in ^{117,119,121,123,125}Cs

Qing-Qing Zhang, Anshul Dadwal, Xiao-Tao He

Published:

Abstract:
The

\begin{document}$ \pi d_{5/2} $\end{document}

rotational bands in odd-even nuclei ^{117,119,121,123,125}Cs are systematically investigated by using the cranked shell model (CSM) with the pairing correlations treated by a particle number conserving (PNC) method in which the blocking effects are taken into account exactly. The experimental observations of the

\begin{document}$ \pi d_{5/2} $\end{document}

bands with two upbendings for ^117,119Cs and one backbending for ¹²⁵Cs are reproduced very well by the PNC-CSM method. Furthermore,

\begin{document}$ \pi d_{5/2} $\end{document}

configuration bands with two upbendings for ¹²¹Cs and one backbending for ¹²³Cs are predicted by the PNC-CSM calculations. The difference between the lighter ^117,119,121Cs and heavier ^123,125Cs isotopes is caused by the evolution of single-particle orbitals near the Fermi surface, and the high-j low-Ω orbital

\begin{document}$ \pi [550]1/2 $\end{document}

plays an important role. The proton shell gap of lighter isotopes is at

\begin{document}$ Z=50 $\end{document}

, while it changes to

\begin{document}$ Z=48 $\end{document}

for heavier ones. For lighter isotopes ^117,119,121Cs, the first upbending is mainly due to the off-diagonal contribution of proton

\begin{document}$ j_{x}(\pi5/2^{-}[532]\pi3/2^{-}[541]) $\end{document}

and

\begin{document}$ j_{x}(\pi1/2^{-}[550]\pi3/2^{-}[541]) $\end{document}

. The second upbending is mainly effected by the off-diagonal contributions of neutron

\begin{document}$ j_{x}(\nu7/2^{-}[523] \nu5/2^{-}[532]) $\end{document}

and

\begin{document}$ j_{x}(\nu3/2^{-}[541] \nu5/2^{-}[532]) $\end{document}

for ^117,119Cs, and the

\begin{document}$ j_{x}(\nu1/2^{-}[541] \nu5/2^{-}[532]) $\end{document}

for ¹²¹Cs, respectively. For heavier isotopes ^123,125Cs, the backbending is attributed mainly to the diagonal parts of proton

\begin{document}$ j_{x}(\pi1/2^{-}[550]) $\end{document}

and

\begin{document}$ \nu7/2^{-}[523] $\end{document}

neutron orbital related terms of diagonal

\begin{document}$ j_{x}(\nu7/2^{-}[523]) $\end{document}

and off-diagonal

\begin{document}$ j_{x}(\nu7/2^{-}[523] \nu5/2^{-}[532]) $\end{document}

contributions.

An effective field theory study of Neutrinoless double beta decay within a Left-Right symmetric model

You-Cai Chen, Ri Guang Huang, Dong-Liang Fang

Published:

Abstract:
In the framework of effective field theory, we derive the formula for the decay width of neutrinoless double beta-decay with the S-matrix theory, considering only the contribution from the exchange of light neutrinos. Our results agree with previous derivations for a Left-Right symmetric model. Detailed analyses of the nuclear matrix elements for ⁷⁶Ge, ⁸²Se, ¹³⁰Te, and ¹³⁶Xe from Quasi-particle Random Phase Approximation method with realistic force and large scale shell model calculations are performed. We compare the results between two many-body approaches and discuss possible origins of the deviation. We also compare our results with those from the so-called master formula, and find decent agreement between the two schemes. A deviation for the q-term in our scheme compared with the counterpart in the master formula can be accounted for as the distortion of the electron wave function under the static Coulomb field. We also provide constraints for the Low energy effective field theory Wilson coefficients

\begin{document}$ C_{VL}^{(6)} $\end{document}

and

\begin{document}$ C_{VR}^{(6)} $\end{document}

from current experimental limits.

Unified Royer Law Revision for α-Decay Half-Lives: Shell Corrections, Pairing, and Orbital-Angular-Momentum

Kai Ren, Pengfei Ma, Minghui Hu, Junlong Tian

Published: , doi: 10.1088/1674-1137/ae167b

Abstract:
The Royer law is a widely used empirical relation for calculating α-decay half-lives but requires 12 parity-dependent parameters. It exhibits systematic deviations near the

\begin{document}$ N = 126 $\end{document}

shell closure. We propose an improved Royer law by adding a shell-correction term, an odd-even pairing indicator, and an orbital-angular-momentum contribution. This unified framework reduces the number of free parameters to just four, leading to significant improvements in accuracy. The root-mean-square deviation across 550 experimental data points decreases from 0.520 to 0.279, corresponding to a 66.7% reduction in parameters and a 46.3% improvement in accuracy. Using this refined formalism, we predict α-decay half-lives for superheavy nuclei with atomic numbers

\begin{document}$ Z = 117-120 $\end{document}

.

Neutrino mass model at a three-loop level from a non-holomorphic modular A₄ symmetry

Takaaki Nomura, Hiroshi Okada

Published:

Abstract:
We study a three-loop induced neutrino mass scenario from a non-holomorphic modular A₄ flavor symmetry and reach the minimum scenario leading predictions of the lepton masses, mixing angles, and Dirac and Majorana phases, which are shown through the chi square analyses. In addition, we discuss the lepton flavor violations, muon anomalous magnetic moment, lepton universality, and relic density of the dark matter candidate. And, we find that we need to extend our model if we satisfy the observed relic density of dark matter within the limit of perturbation where it can be done by adding one singlet scalar boson without changing predictions in neutrino sector.

Interplay of 95 GeV Diphoton Excess and Dark Matter in Supersymmetric Triplet Model

Zetian Li, Ning Liu, Bin Zhu

Published:

Abstract:
The decay of the Higgs boson and the nature of dark matter remain fundamental challenges in particle physics. We investigate the 95 GeV diphoton excess and dark matter within the framework of the triplet-extended Minimal Supersymmetric Standard Model (TMSSM). In this model, an additional Hypercharge

\begin{document}$ Y=0 $\end{document}

,

\begin{document}$ SU(2)_L $\end{document}

triplet superfield is introduced. Mixing between the triplet and doublet Higgs states enhances the diphoton signal strength of the 95 GeV Higgs boson, resulting in

\begin{document}$ \mu_{\gamma\gamma}^{{\rm{CMS+ATLAS}}} = 0.24_{-0.08}^{+0.09} $\end{document}

, which is consistent with experimental observations. This enhancement arises primarily from charged Higgs and chargino loop contributions, together with LEP excess in the

\begin{document}$ Zb\bar{b} $\end{document}

channel around the same mass within the

\begin{document}$ 2\sigma $\end{document}

range. Additionally, the model accommodates viable dark matter candidates in the form of a bino-dominated neutralino. The relic density is reduced to the observed value through resonance-enhanced annihilation via the Higgs portal or co-annihilation with the triplino or higgsino. This reduction remains consistent with constraints from direct and indirect detection experiments. A comprehensive parameter scan demonstrates that the TMSSM can simultaneously explain the 95 GeV diphoton excess, the observed 125 GeV Higgs mass, and the dark matter relic density, establishing a compelling and theoretically consistent framework.

Non-linear corrections to the derivative of nuclear reduced cross-section at small x at a future electron-ion collider

G.R. Boroun

Published:

Abstract:
The determination of non-linear corrections to the nuclear distribution functions due to the HIJING parameterization within the framework of perturbative QCD, specifically the GLR-MQ equations, is discussed. We analyze the possibility of constraining the non-linear corrections present in distribution functions using the inclusive observables that will be measured in future electron-ion colliders. The results show that non-linear corrections play an important role in heavy nuclear reduced cross sections at low x and low

\begin{document}$ Q^2 $\end{document}

values. We find that the non-linear corrections provide the correct behavior of the extracted nuclear cross sections and that our results align with data from the nCETQ15 parameterization group. We are currently discussing a satisfactory description of the non-linear corrections to the shadowing effect at small x.

Impact of new measurements of light quarks at hadron colliders

Zihan Zhao, Minghui Liu, Liang Han

Published:

Abstract:
Recently a series of new measurements with both the neutral and charge current Drell–Yan processes have been performed at hadron colliders, showing deviations from the predictions of the current parton distribution functions (PDFs). In this article, the impact of these new measurements is studied by using their results to update the PDFs. Although these new measurements correspond to different boson propagators and colliding energies, they are found to have a similar impact to the light quark parton distributions with the momentum fraction x around 0.1. It manifests that the deviations are consistent with each other and favor a larger valence

\begin{document}$ d_v/u_v $\end{document}

ratio than the modern PDF predictions. Further study indicates that such tension arises dominantly from the deep inelastic scattering measurements of NMC and the fixed target experiments of NuSea, both of which play pivotal roles in detecting the relative u and d type quark contributions for modern PDFs. According to the conclusions of the impact study, it would be essential to include these new measurements into the complete PDF global analysis in the future.

Experimental overview on the charmed baryon decays

Pei-Rong Li, Xiao-Rui Lyu, Yangheng Zheng

Published:

Abstract:
The charmed baryon was first observed experimentally in 1975, one year after the charm quark's confirmation via the discovery of the

\begin{document}$ J/\psi $\end{document}

particle. Studying charmed baryon decays provides a pathway to investigate both strong and weak interactions, leveraging the weak decays of the embedded charm quark. However, for approximately three decades following its discovery, experimental knowledge of charmed baryons remained significantly limited compared to those of the hidden-charm ψ mesons and open-charm

\begin{document}$ D_{(s)} $\end{document}

mesons. This situation changed markedly starting in 2014, when dedicated data collection for charmed baryons commenced at BESIII. In this article, we review the experimental progress achieved since 2014 in understanding the weak decays of the charmed baryons.

Numerical study on the gauge symmetry of electroweak amplitudes

Wang-Fa Li, Junmou Chen, Qian-Jiu Wang, Zhao-Huan Yu

Published: , doi: 10.1088/1674-1137/ae1185

Abstract:
Electroweak (EW) amplitudes in the gauge-Goldstone five-component formalism have a distinctive property: gauge symmetry is imprinted in the amplitudes, manifested as the massive Ward identity (MWI)

\begin{document}$ k^M{\cal{M}}_M=0 $\end{document}

. In this study, we used the HELAS package to numerically study gauge symmetry in EW amplitudes. First, we directly tested gauge symmetry by examining the MWI of amplitudes. Second, we modified the couplings within a vertex and among vertices to check if and how the MWI changes. Third, we tested gauge symmetry by considering the couplings modified by operators from the standard model effective field theory (SMEFT). Similar to the standard model, there are relations between different couplings that are protected by gauge symmetry. We observed that, if we modify the couplings to deviate from the relations, the MWI is violated. In contrast, the MWI is restored when the relations between couplings reduce to those in the SMEFT.

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