Chinese Physics C

Further study on the lepton mass spectra and flavor mixing with S_3L × S_3R flavor symmetry

Chang-Qi Hu, Chun-Yuan Li, Xiao Liang, Xing-Hua Yang, Dai-Xing Zhang

Published:

Abstract:
Neutrino oscillation experiments have confirmed that neutrinos are massive particles and lepton flavors are mixed. To explain the observed lepton mass spectra and flavor mixing patterns, flavor symmetry plays a crucial and unique role. In this paper, we propose a useful symmetry-breaking scheme by applying

\begin{document}$S_{3L} \times S_{3R} \rightarrow S_{2L} \times S_{2R} \rightarrow \emptyset$\end{document}

within both charged-lepton and neutrino sectors at the mass-matrix level. For the three distinct residual subgroups

\begin{document}$S_{2L}^{(23)} \times S_{2R}^{(23)}$\end{document}

,

\begin{document}$S_{2L}^{(13)} \times S_{2R}^{(13)}$\end{document}

and

\begin{document}$S_{2L}^{(12)} \times S_{2R}^{(12)}$\end{document}

under consideration, we systematically analyze the various parameterizations of the lepton mass matrices. It is shown that all the three scenarios are in good agreement with current neutrino oscillation data. Notably, within the latest best-fit values of neutrino oscillation parameters, the predicted Dirac CP-violating phase δ is calculated to be

\begin{document}$294.6^\circ$\end{document}

,

\begin{document}$302.3^\circ$\end{document}

and

\begin{document}$287.0^\circ$\end{document}

, respectively. To further assess the viability of the model, a comprehensive numerical analysis is performed by utilizing neutrino oscillation parameters at the

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

level. It is found that the allowed range of δ is

\begin{document}$281.2^\circ \rightarrow 338.7^\circ$\end{document}

,

\begin{document}$287.0^\circ \rightarrow 342.2^\circ$\end{document}

and

\begin{document}$282.7^\circ \rightarrow 297.0^\circ$\end{document}

, all fall within its

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

range. These results indicate that the proposed symmetry-breaking scheme

\begin{document}$S_{3L} \times S_{3R} \rightarrow S_{2L} \times S_{2R} \rightarrow \emptyset$\end{document}

can naturally explain the realistic lepton mass hierarchy and mixing pattern, thereby providing valuable theoretical perspectives for future research.

Off-shell modifications of the pion generalized parton distributions and transverse momentum dependent parton distributions

Jin-Li Zhang

Published: , doi: 10.1088/1674-1137/ae28ea

Abstract:
The off-shell characteristics of pion generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs) are examined within the framework of the Nambu–Jona-Lasinio model. In our previous papers, we separately investigated the properties of on-shell pion GPDs and light-front wave functions. It is particularly intriguing to compare the differences between on-shell and off-shell pion GPDs, which allows us to explore the effects associated with off-shellness. Due to the absence of crossing symmetry, the moments of GPDs also incorporate odd powers of the skewness parameter, resulting in new off-shell form factors. Through our calculations, we derived correction functions that account for modifications in pion GPDs due to off-shell effects. Unlike their on-shell counterparts, certain properties break down in the off-shell scenario; for instance, symmetry properties and polynomiality conditions may no longer hold. Additionally, we evaluate off-shell TMDs and compare them with their on-shell equivalents while also investigating their dependence on

\begin{document}$ {\boldsymbol{k}}_{\perp} $\end{document}

.

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.

The images of Brans-Dicke-Kerr type naked singularities

Fen Long, Weike Deng, Xin Qin, Songbai Chen, Jiliang Jing

Published:

Abstract:
We have studied the images of the Brans-Dicke-Kerr spacetime with a dimensionless Brans-Dicke parameter ω, which belongs to axisymmetric rotating solutions in the Brans-Dicke theory. Our results show that the Brans-Dicke-Kerr spacetime with the parameter

\begin{document}$ \omega>-3/2 $\end{document}

represents naked singularities with distinct structures. For the case with

\begin{document}$ a \leqslant M $\end{document}

, the shadow in the Brans-Dicke-Kerr spacetime persists, gradually becomes flatter and smaller as ω decreases. Especially when

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

, the shadow in the image exhibits a very special "jellyfish" shape and possesses a self-similar fractal structure. For the case with

\begin{document}$ a > M $\end{document}

, a distinct gray region consisting of two separate patches appears in the image observed by equatorial observers. This indicating that the Brans-Dicke-Kerr spacetime can be distinguished from the Kerr and Kerr-de Sitter cases based on its image. These effects of the Brans-Dicke parameter could help us to reveal the intrinsic structure of the Brans-Dicke-Kerr spacetimes and provide a foundation for testing Brans-Dicke theory through future high-precision observations.

One-loop expressions for H^± → W^±Z and their implications at muon-TeV colliders

Dzung Tri Tran, Quang Hoang-Minh Pham, Khoa Ngo-Thanh Ho, Khiem Hong Phan

Published: , doi: 10.1088/1674-1137/ae2660

Abstract:
One-loop contributions for decay process

\begin{document}$ H^{\pm} \rightarrow W^{\pm}Z $\end{document}

within the Two-Higgs-Doublet Model (THDM) is computed in the general

\begin{document}$ {\cal{R}}_{\xi} $\end{document}

gauge, and its phenomenological applications at future muon–TeV colliders are studied in this paper. The analytic results are confirmed by several consistency tests, for example, the ξ-independence, the renormalization-scale stability and the ultraviolet finiteness of the one-loop amplitude. We first perform an updated parameter scan of the Type-X THDM in the phenomenological studies. The production of charged Higgs boson pairs at future muon–TeV colliders is then investigated through the two processes

\begin{document}$ \mu^+\mu^- \rightarrow H^+H^- \rightarrow W^{\pm}W^{\mp}Zh $\end{document}

and

\begin{document}$ \mu^+\mu^- \rightarrow \gamma\gamma \rightarrow H^+H^- \rightarrow W^{\pm}W^{\mp}Zh $\end{document}

. Both signal events and their significances are evaluated with taking into account the corresponding Standard Model backgrounds. We find that the signal significances can exceed

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

at several benchmark points in the viable parameter space of the Type-X THDM.

Gravitational waveforms from periodic orbits around a charged black hole with scalar hair

Weike Deng, Sheng Long, Tan Qin, Jiliang Jing

Published: , doi: 10.1088/1674-1137/ae28eb

Abstract:
We investigate geodesic motion and gravitational-wave signatures of charged black holes with scalar hair. Using the effective potential approach, we analyze marginally bound orbits and innermost stable circular orbits, showing how their positions and energy thresholds are modified by the scalar hair parameter

\begin{document}$ r_B $\end{document}

. These results demonstrate scalar hair's role in altering the boundary of stable motion. We further explore periodic orbits characterized by rational frequency ratios, labeled by the index

\begin{document}$ (z,w,v) $\end{document}

, and quantify how scalar hair affects their orbital energy and angular momentum. Based on these orbital properties, we compute gravitational waveforms from extreme mass-ratio inspirals where a stellar-mass compact object orbits a supermassive charged black hole with scalar hair. Using the numerical kludge method, we generate waveforms that exhibit clear zoom-whirl patterns with morphology visibly affected by

\begin{document}$ r_B $\end{document}

. Our results show that scalar hair leaves distinguishable imprints on waveforms, suggesting future space-based detectors could probe deviations from classical black hole spacetimes through extreme mass-ratio inspirals observations.

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.

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.

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}

.

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.

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.

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.

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.

Spatially covariant gravity with two degrees of freedom in the presence of an auxiliary scalar field: Hamiltonian analysis

Jun-Cheng Zhu, Shu-Yu Li, Xian Gao

Published:

Abstract:
A class of gravity theories respecting spatial covariance and in the presence of non-dynamical auxiliary scalar fields with only spatial derivatives is investigated. Generally, without higher temporal derivatives in the metric sector, there are 3 degrees of freedom (DOFs) propagating due to the breaking of general covariance. Through a Hamiltonian constraint analysis, we examine the conditions to eliminate the scalar DOF such that only 2 DOFs, which correspond the tensorial gravitational waves in a homogeneous and isotropic background, are propagating. We find that two conditions are needed, each of which can eliminate half degree of freedom. The second condition can be further classified into two cases according to its effect on the Dirac matrix. We also apply the formal conditions to a polynomial-type Lagrangian as a concrete example, in which all the monomials are spatially covariant scalars containing two derivatives. Our results are consistent with the previous analysis based on the perturbative method.

A Classical Interpretation of the Nonrelativistic Quark Potential Model: Color Charge Definition and the Meson Mass-Radius Relationship

ZhiGuang Tan, YouNeng Guo, ShengJie Wang, Hua Zheng

Published: , doi: 10.1088/1674-1137/ae28e9

Abstract:
Quantum Chromodynamics (QCD) is the fundamental theory describing quark interactions, and various quark models based on QCD have been widely used to study the properties of hadrons, including their structures and mass spectra. However, unlike Quantum Electrodynamics (QED) and the Bohr model of hydrogen atom, there is no direct classical analogy for hadronic structures. This paper presents a classical interpretation of the nonrelativistic quark potential model, providing a more intuitive and visualizable description of strong interactions through the quantitative formulation of color charge and color flux. Furthermore, we establish the relationship between meson mass and its structural radius in the nonrelativistic framework and estimate the key parameters of our model using available data from

\begin{document}$ \eta_b(1S) $\end{document}

and

\begin{document}$ \Upsilon(1S) $\end{document}

. We then extend this relationship to a broader range of excited meson states, obtaining their structural radii that show good agreement with the root mean square (RMS) radius or charge radius predicted by QCD calculations.

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.

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}

.

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.

Just Accepted