Chinese Physics C

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}

.

0νββ decay nuclear matrix elements under Left-Right symmetric model from the spherical quasi-particle random phase approximation method with realistic force

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

Published:

Abstract:
We perform the calculation of nuclear matrix elements for the neutrinoless double beta decays under a Left-Right symmetric model mediated by light neutrinos, and we adopt the spherical quasi-particle random-phase approximation (QRPA) approach with a realistic force. For eight nuclei: ⁷⁶Ge, ⁸²Se, ⁹⁶Zr, ¹⁰⁰Mo, ¹¹⁶Cd, ¹²⁸Te, ¹³⁰Te, and ¹³⁶Xe, related nuclear matrix elements are given. We analyze each term, and the details of contributions from different parts are also provided. For the q term, we find that the weak-magnetism components of the nucleon current contribute equally to other components such as the axial-vector. We also discuss the influence of short-range correlations on these NMEs. It is found that the R term is more sensitive to short-range correlations than other terms due to the large portion of the contribution from high exchange momenta.

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.

Dynamic shadow of a black hole with a self-interacting massive complex scalar hair

Mingzhi Wang, Cheng-Yong Zhang, Songbai Chen, Jiliang Jing

Published:

Abstract:
We research dynamic shadows of a black hole with a self-interacting massive complex scalar hair. The complex scalar field

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

evolves with time t, whose magnitude on apparent horizon

\begin{document}$|\psi_{h}|$\end{document}

starts from zero, undergoes a sharp rise followed by rapid oscillations, and eventually converges to a constant value. The variation of the photon sphere radius

\begin{document}$r_{ps}$\end{document}

is similar to that of the magnitude

\begin{document}$|\psi_{h}|$\end{document}

. The emergence of the complex scalar hair

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

causes the apparent horizon radius

\begin{document}$r_{h}$\end{document}

to start increasing sharply, and smoothly approaches a stable value eventually. The shadow radius

\begin{document}$R_{sh}$\end{document}

of the black hole with an accretion disk increases with

\begin{document}$t_{o}$\end{document}

the time at the observer's position. In the absence of an accretion disk, the shadow radius

\begin{document}$R_{sh}$\end{document}

is larger and also increases as

\begin{document}$t_{o}$\end{document}

increases. Furthermore, we slice the dynamical spacetime into spacelike hypersurfaces for all time points

\begin{document}$t$\end{document}

. For the case with an accretion disk, the variation of

\begin{document}$R_{sh}$\end{document}

is similar to that of the apparent horizon

\begin{document}$r_{h}$\end{document}

, because the inner edge of the accretion disk extends to the apparent horizon. In the absence of an accretion disk, the variation of

\begin{document}$R_{sh}$\end{document}

is similar to that of the photon sphere

\begin{document}$r_{ps}$\end{document}

, because the black hole shadow boundary is determined by the photon sphere. Since the variation of

\begin{document}$r_{ps}$\end{document}

is induced by

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

, it can be stated that the variation in the size of the shadow is likewise caused by the change of

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

. Regardless of the presence or absence of the accretion disk, the emergence of the complex scalar hair

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

causes the radius

\begin{document}$R_{sh}$\end{document}

of the shadow to start changing. Moreover, we investigate the time delay

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

of lights propagating from light sources to observer. These findings not only enrich the theoretical models of dynamic black hole shadows but also provide a foundation for testing black hole spacetime dynamics.

Prospects for probing dark matter particles and primordial black holes with the Square Kilometre Array using the 21 cm power spectrum at cosmic dawn

Meng-Lin Zhao, Yue Shao, Sai Wang, Xin Zhang

Published:

Abstract:
Probing the nature of dark matter (DM) remains an outstanding problem in modern cosmology. The 21 cm signal, as a sensitive tracer of neutral hydrogen during cosmic dawn, provides a unique means to investigate DM nature during this critical epoch. Annihilation and decay of DM particles, as well as Hawking radiation of primordial black holes (PBHs), can modify the thermal and ionization histories of the early universe, leaving distinctive imprints on the 21 cm power spectrum. Therefore, the redshifted 21 cm power spectrum serves as a powerful tool to investigate such DM processes. In this work, we systematically assess the potential of the upcoming Square Kilometre Array (SKA) to constrain DM and PBH parameters using the 21 cm power spectrum. Assuming 10,000 hours of integration time, the SKA is projected to reach sensitivities of

\begin{document}$ \langle\sigma v\rangle \leq 10^{-28}\,{{\rm{cm}}}^{3}\,{{\rm{s}}}^{-1} $\end{document}

and

\begin{document}$ \tau\geq 10^{28}\,{{\rm{seconds}}} $\end{document}

, for

\begin{document}$ 10 {{\rm{GeV}}} $\end{document}

DM particles. It can also probe PBHs with masses of

\begin{document}$ 10^{16}\,{{\rm{g}}} $\end{document}

and abundances

\begin{document}$ f_{{{\rm{PBH}}}} \leq 10^{-6} $\end{document}

. These results indicate that the SKA could place constraints on DM annihilation, decay, and PBH Hawking radiation that are up to two to three orders of magnitude stronger than current limits. Furthermore, the SKA is expected to exceed existing bounds on sub-GeV DM and to probe Hawking radiation from PBHs with masses above

\begin{document}$ 10^{17}\,{{\rm{g}}} $\end{document}

, which are otherwise inaccessible by conventional cosmological probes. Overall, the SKA holds great promise for advancing our understanding of both DM particles and PBHs, potentially offering new insights into the fundamental nature of DM.

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.

Search for the lepton number violating process ${{\boldsymbol J}/{\boldsymbol\psi }{\bf\to}{\boldsymbol K}^{\bf +}{\boldsymbol K}^{\bf +}{\boldsymbol e}^{\bf -}{\boldsymbol e}^{\bf -}{\bf +}{\boldsymbol {c.c.}}}$

M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, R. Aliberti, A. Amoroso, Q. An, Y. Bai, O. Bakina, Y. Ban, H.-R. Bao, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, H. Cai, M. H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin, X. Y. Chai, J. F. Chang, T. T. Chang, G. R. Che, Y. Z. Che, C. H. Chen, Chao Chen, G. Chen, H. S. Chen, H. Y. Chen, M. L. Chen, S. J. Chen, S. L. Chen, S. M. Chen, T. Chen, X. R. Chen, X. T. Chen, X. Y. Chen, Y. B. Chen, Y. Q. Chen, Z. Chen, Z. K. Chen, J. C. Cheng, L. N. Cheng, S. K. Choi, X. Chu, G. Cibinetto, F. Cossio, J. Cottee-Meldrum, H. L. Dai, J. P. Dai, A. Dbeyssi, R. E. de Boer, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, B. Ding, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, M. C. Du, S. X. Du, X. L. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, Y. H. Fan, J. Fang, S.

Published:

Abstract:
Based on

\begin{document}$ (10087\pm 44)\times10^{6} $\end{document}

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

events collected with the BESIII detector, we search for the lepton number violating decay

\begin{document}$ J/\psi \to K^+K^+e^-e^- + c.c. $\end{document}

for the first time. The upper limit on the branching fraction of this decay is set to be

\begin{document}$ 2.1 \times 10^{-9} $\end{document}

at the 90% confidence level with a frequentist method. This is the first search for

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

decays with the lepton number change by two, offering valuable insights into the underlying physical processes.

A Numerical Study on Gauge Symmetry of Electroweak Amplitudes

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

Published:

Abstract:
Electroweak (EW) amplitudes in the gauge-Goldstone 5-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 paper, we use the HELAS package to numerically study gauge symmetry in EW amplitudes. First, we directly test gauge symmetry by examining the MWI of amplitudes. Second, we modify the couplings within a vertex and of vertices to check if and how the MWI changes. Third, we test 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 find that if we modify the couplings to deviate from the relations, the MWI is violated. On the other hand, the MWI is restored when the relations between couplings reduce to those in the SMEFT.

Null test of cosmic curvature using deep learning method

Li Tang, Liang Liu, Ying Wu

Published:

Abstract:
Determining the spatial curvature of the Universe, a fundamental parameter defining the global geometry of spacetime, remains crucial yet contentious due to existing observational tensions. Although Planck satellite measurements have provided precise constraints on spatial curvature, discrepancies persist regarding whether the Universe is flat or closed. Here, we introduce a model-independent approach leveraging deep learning techniques, specifically residual neural networks (ResNet), to reconstruct the dimensionless Hubble parameter E(z) and the normalized comoving distance D(z) from H(z) data and multiple SNe Ia compilations. Our dual-block ResNet architecture, which integrates a model-driven block informed by

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

CDM and a purely data-driven block, yields smooth and robust reconstructions and enables the derivation of D'(z). By combining these reconstructed quantities, we assess the curvature diagnostic function

\begin{document}$ {\cal{O}}_k(z) $\end{document}

. Analyses of the Pantheon+ sample support spatial flatness at the 1

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

level over 0 < z < 2.5, with a mild tendency toward negative curvature at high redshift. Reconstructions based on Union3 and DESY5, however, show stronger departures toward negative curvature at intermediate and high redshifts. These results highlight the need for expanded and refined observational datasets to conclusively resolve these tensions and comprehensively investigate cosmic geometry.

Nuclear temperature of spectator source extracted by neutron spectra in ¹²⁴Sn,¹⁰⁷Sn + ¹²⁰Sn collisions at 600 MeV/nucleon

Huixiao Duan, Fan Zhang, Kailei Wang, Jun Su

Published:

Abstract:
The properties of neutrons from spectator sources produced in ^107,124Sn + ¹²⁰Sn collisions at 600 MeV/nucleon are studied. The isospin-dependent quantum molecular dynamics (IQMD) model is used to describe the dynamical process of the fragmentation, and the statistical model GEMINI is applied to simulate the secondly decay of the pre-fragments. The differential cross section and multiplicity of the neutrons emitted from the spectator source are used to prove the feasibility of the model. The temperatures of the spectator source are extracted by two-source-fitting the transverse momentum distributions of the neutrons using the classical Maxwellian functions. The temperatures of the spectator sources extracted from calculations are consistent with the experimental data, those from the SMM model, and the isotopic temperature

\begin{document}$ T_{\text{HeLi}} $\end{document}

. However, the participant source exhibits anomalously high temperatures. Our work suggests the possible model-errors of the IQMD+GEMINI model when describing the neutron emission from the participant source, which is of reference for the further development of the model.

New Physics Search at the CEPC: a General Perspective

Xiaocong Ai, Stefan Antusch, Peter Athron, Yunxiang Bai, Shou-Shan Bao, Daniele Barducci, Xiao-Jun Bi, Tianji Cai, Lorenzo Calibbi, Junsong Cang, Junjie Cao, Wei Chao, Boping Chen, Gang Chen, Long Chen, Mingshui Chen, Shanzhen Chen, Xiang Chen, Huajie Cheng, Huitong Cheng, Yaodong Cheng, Kingman Cheung, Min-Huan Chu, João Barreiro Guimarães da Costa, Xinchen Dai, Arindam Das, Zhi-fu Deng, Frank F. Deppisch, P. S. Bhupal Dev, Yabo Dong, Marco Drewes, Xiaokang Du, Yong Du, Jun Fan, Yaquan Fang, Cunfeng Feng, Andrew Fowlie, Hao-fei Gao, Jie Gao, Lin-Qing Gao, Meisen Gao, Yu Gao, Yuanning Gao, Bruce Mellado Garcia, Shao-Feng Ge, Ti Gong, Jiayin Gu, Lei Guo, Pei-Hong Gu, Yu-Chen Guo, Zhi-Hui Guo, Jan Hajer, Rabia Hameed, Chengcheng Han, Shuo Han, Tao Han, Xiqing Hao, Hong-Jian He, Xiaogang He, Yangle He, Sven Heinemeyer, Zhaoxia Heng, Xiao-Hui Hu, Fa Peng Huang, Fei Huang, Yanping Huang, Jianfeng Jiang, Xu-Hui Jiang, Hong-Bo Jin, Mingjie Jin, Shan Jin, Wenyi Jin, Mussawir Khan, Honglei Li, Jiarong Li, Jinmian Li

Published:

Abstract:

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}

Breakup of ⁷Li in the field of ^118,120Sn nuclei and its effect on the elastic scattering channel

N. Amangeldi, N. Burtebayev, G. Yergaliuly, Maulen Nassurlla, B. Balabekov, Abylay Tangirbergen, Awad A. Ibraheem, Mohamed A. Dewidar, Sh. Hamada

Published:

Abstract:
The breakup of weakly bound projectiles has been shown to significantly influence scattering processes, including elastic scattering. In this context, we revisit the angular distributions (ADs) for elastic scattering of ⁷Li from ¹¹⁸Sn and ¹²⁰Sn targets. The study analyzes ⁷Li + ¹¹⁸Sn ADs over the energy range 18.15–48 MeV and ⁷Li + ¹²⁰Sn ADs from 20–44 MeV, utilizing various nuclear interaction models. These include the São Paulo potential, the CDM3Y6 potential (with and without rearrangement term), and cluster folding model. Results indicate that the real component of the folded potentials must be scaled down by 40–65% to achieve an accurate fit to the experimental ADs, underscoring the prominent role of ⁷Li breakup effects. Interestingly, the conventional threshold anomaly observed in reactions involving tightly bound nuclei is not present. Further analysis using the continuum discretized coupled channels (CDCC) approach provides excellent agreement with the data, reinforcing these findings.

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.

Anisotropic quark propagation and Zeeman effect in an external magnetic field

Minghui Ding, Fei Gao, Sebastian M. Schmidt

Published:

Abstract:
We investigated the impact of a constant external magnetic field on the dressed propagators of up-, down-, and strange quarks. In the weak field limit, we derive a general momentum-space representation for the propagator and numerically solve the corresponding gap equation. Our analysis reveals that the vector term of the propagator can be decomposed into components parallel and perpendicular to the magnetic field, resulting in anisotropic effective masses, with the transverse mass consistently exceeding the longitudinal mass. This mass disparity exhibits a power law dependence on the magnetic field strength and is less pronounced for the strange quark compared to up and down quarks. Additionally, the magnetic field induces axial-vector and tensor terms, highlighting the Zeeman effect resulting from quark interactions with the magnetic field. These findings have important implications for (inverse) magnetic catalysis, and phenomena such as vector meson and pion condensations.

Extracting the kinetic freeze-out properties of high energy pp collisions at the LHC with event shape classifiers

Jialin He, Xinye Peng, Zhongbao Yin, Liang Zheng

Published:

Abstract:
Event shape measurements are crucial for understanding the underlying event and multiple-parton interactions (MPIs) in high energy proton-proton (pp) collisions. In this paper, the Tsallis Blast-Wave model with independent non-extensive parameters for mesons and baryons, was applied to analyze transverse momentum spectra of charged pions, kaons, and protons in pp collision events at

\begin{document}$ \sqrt{s}=13 $\end{document}

TeV classified by event shape estimators relative transverse event activity, unweighted transverse spherocity, and flattenicity. Our analysis reveals consistent trends in the kinetic freeze-out temperature and non-extensive parameter across different collision systems and event shape classes. The use of diverse event-shape observables in pp collisions has significantly expanded the accessible freeze-out parameter space, allowing for a more comprehensive exploration of its boundaries. Among these event shape classifiers, flattenicity emerges as a unique observable for disentangling hard process contributions from additive MPI effects, allowing the isolation of collective motion effects encoded by the radial flow velocity. Through the analysis of the interplay between event-shape measurements and kinetic freeze-out properties, we gain deeper insights into the mechanisms responsible for flow-like signatures in pp collisions.

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.

$ {\boldsymbol\rho\bf\to \boldsymbol\pi\boldsymbol\pi }$ Hadronic Decay in the Nambu-Jona-Lasinio Model: Mass-Width Interplay and Beyond-RPA Corrections

Qing-Wu Wang, Xiao-Fu Łü, Hua-Zhong Guo

Published:

Abstract:
A novel framework for analyzing unstable composite particles using Green's functions and dispersion relations is presented. As an illustrative example, we explore the ρ vector meson decay process

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

within the Nambu -- Jona - Lasinio (NJL) model. This approach addresses a key limitation of the four-quark interaction description, which adequately describes two-quark bound states but fails to describe decay processes. The Bethe-Salpeter(BS) wave function of the ρ meson exhibits time evolution that leads to the physical mass M incorporating a correction

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

. This correction depends on the decay width

\begin{document}$\Gamma(M)$\end{document}

. This work provides crucial insights into the dynamical relationship between resonance masses and their decay properties, addressing a long-standing challenge in hadron physics. The calculated mass and width are in good agreement with the experimental values, demonstrating the effectiveness of this approach for studying unstable hadronic systems beyond conventional bound-state approximations.

The Role of Fission in Mass Sensitivity Study of the r-process

Yi Wei Hao, Yi Fei Niu, Zhong Ming Niu

Published: , doi: 10.1088/1674-1137/adfe55

Abstract:
A sensitivity study was performed to investigate the impact of individual nuclear masses on r-process rare-earth peak abundances in different astrophysical scenarios. The most impactful nuclei are primarily distributed in two regions on the nuclear chart: one located 20-30 neutrons away from stability (defined as region I) and another 7-15 neutrons away from stability (defined as region II), as previously reported in Phys. Lett. B 844, 138092 (2023). In this work, we extend our analysis by focusing on the role of fission in the mass sensitivity study. The results show that in astrophysical scenarios involving fission, the sensitivity of nuclei in region I is diminished due to the deposition of a large number of fission fragments in the rare-earth mass region. However, nuclei in region II retain high sensitivity because the contribution of fission decreases in the later stages of nucleosynthesis. This study highlights the impact of fission on the sensitivity of r-process abundances to nuclear masses and helps to enhance the understanding of the rare-earth peak formation mechanism.

Existence of quark stars in gravity's Rainbow: the significance of strongly interacting quark matter

Ayan Banerjee, Indrani Karar, Javlon Rayimbaev, Inomjon Ibragimov, Sardor Murodov, Sokhibjan Muminov, Sardor Jumaniyozov

Published:

Abstract:
This paper explores the internal composition and equation of state (EoS) of quark stars (QSs) characterised by pressure anisotropy, considering recent astrophysical findings within the framework of gravity's rainbow. By employing perturbative quantum chromodynamics (QCD) corrections and the concept of color superconductivity, the EoS was formulated as a dimensionless function reliant on a single parameter, thereby offering an in-depth analysis of the effects of strong interactions. The study is further extended by rescaling the EoS and applying dimensionless variables, thus covering a range from non-interacting quark matter to extreme stiffness characterized by a parameter

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

. We also show that including the fluid anisotropy permits stiffer EoS, facilitating the modelling of configurations that adequately meet observational constraints. We then use the supposed EoSs to numerically solve the modified Tolman-Oppenheimer-Volkoff (TOV) equations and examine the effects of anisotropy and rainbow parameters on star mass, radius, and compactness. The paper also explores the static stability, the adiabatic index, and sound velocity profiles, thoroughly explaining QS behaviour. Overall, this study offers valuable insights into the characteristics of QSs and their consistency with observational data, providing a comprehensive analysis of their EoS and internal structure.

Examination of proton radioactivity in exotic nuclei with a deformed Gamow-like model

Zhe Wang, Quan Liu, Jian-You Guo

Published: , doi: 10.1088/1674-1137/ae042f

Abstract:
We have modified the Deformed Gamow-like Model (DGLM) by incorporating the impact of daughter nucleus deformation on the Coulomb interaction between the daughter nucleus and emitted proton. Using this modified DGLM, we have systematically calculated the half-lives of both single-proton and two-proton radioactivity within a unified framework. The computational results demonstrate remarkable consistency with experimental radioactivity half-lives. Additionally, our study explores how deformation influences penetration probabilities and establishes a universal curve that relates penetration probability to experimental half-lives, thereby validating the efficacy of the DGLM. We also made unified predictions for the half-lives of potential single-proton and two-proton radioactive nuclei, which align well with other models, underscoring the reliability of the DGLM in predicting proton radioactivity.

Study the yrast and yrare low-lying excited states using machine learning approaches

Z. L. Li, B. F. Lv, Y. J. Wang, C. M. Petrache

Published: , doi: 10.1088/1674-1137/adfe54

Abstract:
The low-lying excitation energies of the

\begin{document}$2_1^+, 4_1^+,2_2^+, 0_2^+,3_1^-, 0_3^+$\end{document}

states in even-even nuclei are studied with two modern machine learning algorithms: the Light Gradient Boosting Machine (LightGBM) and Sparse Variational Gaussian Process (SVGP). The obtained results demonstrate that both LightGBM and SVGP perform well within the training and validation datasets when informed by a physics-based feature space. A detailed comparison with the results obtained for

\begin{document}$2_1^+$\end{document}

and

\begin{document}$2_2^+$\end{document}

states using the Hartree-Fock-Bogoliubov theory extended by the generator coordinate method and mapped onto a five-dimensional collective quadrupole Hamiltonian, shows that both ML algorithms outperform this model in accuracy. The extrapolation capabilities of these algorithms were further validated using newly measured 12 data points of

\begin{document}$2_1^+$\end{document}

and

\begin{document}$2_2^+$\end{document}

states, which were not included in the training set. In addition, the partial dependence plot method and the shapley additive explanations method are used as interpretability tools for analyzing the relationship between input features and model predictions. These tools provide in-depth insights into how the input features influence the prediction of low-lying excitation energies and help identify the most important features that drive the prediction, being valuable for understanding the low-lying excitation energies.

Radial oscillations of neutron stars within density-dependent relativistic-mean field model

Published:

Abstract:
The radial oscillations of neutron stars are studied using equations of state derived from density-dependent relativistic mean-field (DDRMF) models, which effectively describe the ground-state properties of finite nuclei. A novel numerical approach, the finite volume method (FVM), is employed to solve the eigenvalue problem associated with oscillation frequencies. Compared to conventional methods such as the finite difference method and shooting method, the FVM avoids the numerical instability encountered at high frequencies with an equation of state that includes a discontinuous adiabatic index and offers greater computational efficiency. The oscillation frequencies of high-order modes exhibit a similar trend of change. The radial displacements and pressure perturbations are largely influenced by the EOSs of crust region.The frequency of the first excited state shows a strong linear relationship with both the slope and skewness parameters of the symmetry energy. These findings suggest that the density dependence of the symmetry energy can be constrained through observations of neutron star radial oscillation frequencies.

Correspondence between grey-body factors and quasinormal modes for regular black holes with sub-Planckian curvature

Published: , doi: 10.1088/1674-1137/adfa74

Abstract:
We investigate the quasi-normal modes (QNMs) under the gravitational field perturbations and the grey-body factors for a class of regular black holes with sub-Planckian curvature and Minkowski core. Specifically, we compute the QNMs with the pseudospectral method and the WKB method. It is found that as the deviation parameter of the regular black hole changes, the trajectory of the QNMs displays non-monotonic and spiral behavior. Then we compute the grey-body factors with the WKB method and compare them with the results obtained by the correspondence relation recently revealed in [1]. We find the discrepancy exhibits minor errors, indicating that this relation is effective for computing the grey-body factors of such regular black holes.

Physical parameter regression from black hole images via a multiscale adaptive neural network

Published:

Abstract:
High-precision regression of physical parameters from black hole images generated by General Relativistic Ray Tracing (GRRT) is essential for investigating spacetime curvature and advancing black hole astrophysics. However, due to limitations in observational resolution, high observational costs, and imbalanced distributions of positive and negative samples, black hole images often suffer from data scarcity, sparse parameter spaces, and complex structural characteristics. These factors pose significant challenges to conventional regression methods based on simplified physical models. To overcome these challenges, this study introduces Multiscale Adaptive Network (MANet), a novel regression framework grounded in deep learning. MANet integrates an Adaptive Channel Attention (ACA) module to selectively enhance features in physically informative regions. Meanwhile, a Multiscale Enhancement Feature Pyramid (MEFP) is employed to capture fine-grained spatial structures such as photon rings and accretion disks, while alleviating information loss due to downsampling. Experimental evaluations on GRRT-simulated datasets demonstrate that MANet substantially improves parameter estimation accuracy and generalization capability in high-dimensional parameter spaces, outperforming existing baseline approaches. This framework presents a promising avenue for high-precision parameter regression in Event Horizon Telescope (EHT) data analysis and broader astrophysical imaging applications characterized by sparse and noisy data.

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.

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.

Stellar Configurations in f(R, L_m, T) Gravity: Probing Anisotropy and Stability via Minimal Geometric Deformation

M. Zubair, Hira Sohail, Saira Waheed, Amara Ilyas, Irfan Mahmood

Published:

Abstract:
The present study uses the minimal geometric deformation scheme within the paradigm of

\begin{document}$ f({\cal{R}},{\cal{L}}_m,T) $\end{document}

gravity to model anisotropic compact stars using class-1 embedding spacetime. We introduce deformation of radial component of metric tensor which results in the decoupling of Einstein field equations and introduces an additional gravitational source. The involved constants are then evaluated by adopting the data of seven realistic star candidates through matching of inner region with outer Schwarzschild line element. A comprehensive investigation of three compact stars is done graphically to examine the impact of coupling parameter β and the deformation parameter n, revealing positive well-behaved energy densities and pressures, satisfying energy conditions. The study finds that negative coupling parameter β values allow more mass accumulation while maintaining the crucial physical characteristics such as stability through Herrera's cracking condition and the extended Tolman-Oppenheimer-Volkoff equation. This study emphasizes the importance of gravitational decoupling for mass, redshift and compactness, providing vital insights into the internal structure of stellar bodies within this new generalized gravity framework.

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.

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