The theoretical study aims to synthesize superheavy elements with Z >= 114 by irradiating an actinide target with a beam heavier than Ca-48 .The results of the( 244)Pu(Ti-50,xn)(294-x) Lv reaction are in good agreement with the experimental results first published by Lawrence Berkeley National Laboratory. The research indicates that reactions using Ti-50 have higher cross sections for the production of superheavy elements compared to reactions using Cr-54 . The production cross section for the Bk-249(Ti-50, xn) (299-x)119 reaction is predicted to be sigma(prod) = 21.72 fb at a center-of-target center-of-mass energy of 226(2) MeV, while for the Cf-249(Ti-50, xn)(299-x)120 reaction, it is predicted to be sigma(prod) = 1.80 fb at a higher center-of-target center-of-mass energy of 233(2) MeV. This suggests that with a Ti-50 beam, there is potential for synthesizing super heavy elements near the island of stability, as well as new elements beyond Z = 118 .

A series of findings in machine learning (ML) and decay theory are captured while exploring the role of deformation and preformation factors in alpha decay. We provide a novel and practical paradigm for developing physics-driven ML in nuclear physics research by introducing known decay theory and statistical correlation analysis. Furthermore, this analysis verifies the Geiger-Nuttall law, and the relationship between the decay energy and alpha formation amplitude, also releases a signal that nuclei with hexadecapole deformation are more likely to form alpha clusters. In particular, we identify two novel phenomena, shape inheritance, in which the deformation properties are partially transmitted from parent to daughter nuclei; and half-life inversion due to shape staggering of adjacent even-even nuclei. This phenomenon occurs frequently in neutron-deficient nuclei near lead isotopes, which is consistent with shape coexistence in experiments. Surprisingly, it reappeared within the predicted halflife of the 119 and 120 isotope chains in the eighth period of the periodic table. The half-life considering the inversion effect is preferable for the study of new nuclides and shape coexistence in experiments.

This study uses machine learning, specifically transfer learning with neural networks, to improve the predictions of fission barrier heights and ground state binding energies of superheavy nuclei, which are crucial for calculating survival probabilities in fusion reactions. Transfer learning for neural networks involve two stages: pre-training and fine-tuning, each utilizing a distinct pre-training dataset and target dataset. In this work, we split the pre-training data into 60% for training and 40% for validation, while the target data are partitioned into 20% for test, with the remaining 80% further divided into 60% for training and 40% for validation. To construct the neural-network model, we adopt the proton number Z and mass number A as the input layer, employ two hidden layers, each containing 128 neurons with rectified linear unit (ReLU) activation, and set the learning rate to 0.001. For the fission-barrier-height model, the pre-training dataset is either the FRLDM or the WS4 model data, with the experimental measurements serving as the target set. For the ground-state binding-energy model, we first calculate the residuals between WS4 predictions and the AME2020 evaluation, then divide these residuals into a light-nucleus subset and a heavy-nucleus subset according to proton number. The light-nucleus subset is used for pre-training, and the heavy-nucleus subset for fine-tuning. After optimization, the root-mean-square error (RMSE) of the FRLDM barrier model decreases from 1.03 MeV to 0.60 MeV, and that of the WS4 barrier model drops from 0.97 MeV to 0.61 MeV. For the binding-energy model, the RMSE decreases from 0.33 to 0.17 MeV on the test set and from 0.29 MeV to 0.26 MeV on the full data set. We also present the performances of the fission-barrier model before and after refinement, together with the predicted barrier heights along the isotopic chains of the new elements Z = 119 and Z = 120, and analyze the reasons for the differences in the results obtained by different models. We hope that these results will serve as a useful reference for future theoretical studies. The datasets in this paper are openly available at https://www.doi.org/10.57760/sciencedb.28388.

Compton scattering is a fundamental process in QED with broad applications, yet its theoretical description at high energies is challenged by substantial next-to-leading order corrections arising from double-logarithmic enhancements. To address this, we report the first calculation of the next-to-next-to-leading order (NNLO) total cross section with full electron mass dependence. Our analysis reveals that the NNLO correction, albeit still containing double logarithms, is numerically small due to a suppressing prefactor. By identifying the origin of these logarithms in a kinematic regime featuring a Glauber electron exchange, we successfully resum the leading logarithmic series to all orders, obtaining a compact result in terms of a modified Bessel function. The all-order structure reveals a suppression mechanism, which explains the rapid convergence of higher-order contributions. The combination of our NNLO calculation and all-orders resummation delivers a reliable and precise prediction, poised to serve the needs of high-precision experiments in the foreseeable future.

We investigate the processes e+e− → ηc + γ and e+e− → χcJ + γ at B factories within the NRQCD factorization framework, computing the corresponding helicity amplitudes through 𝒪(α_s^2) . The short-distance coefficients are obtained as series expansions in r=4m_c^2/s around r = 0, 1/3, 2/3, 1, using the method of differential equations. By combining the expansions from all four points, we construct composite asymptotic expressions that reproduce the exact results accurately over the full range 0 ≤ r ≤ 1, with relative errors below 0.1 α_θ^H , which are insensitive to NRQCD matrix elements and exhibit small theoretical uncertainties. These parameters further display good stability across different perturbative orders. With the high luminosity anticipated at Belle 2, future experimental measurements will thus provide a clear test of NRQCD factorization.

To optimize the reaction conditions for synthesizing the superheavy element Z=119,we examined vari-ous combinations of projectiles and target nuclei used by different countries:Japan with 51V+248Cm,Russia poten-tially with 50Ti+249Bk,and China currently with 54Cr+243Am.Systematic investigations were conducted by vary-ing the incident energy from 210 MeV to 260 MeV.We analyzed the capture cross sections,fusion probabilities,survival probabilities,and evaporation residue cross sections(ERCS)for each reaction to identify the optimal incid-ent energy for synthesizing Z=119.Detailed plots were generated for these parameters as functions of the incident energy,thereby providing valuable insights for selecting the most effective incident energy for synthesizing Z=119.

The accuracy of the Finite-Range Droplet Model 2012 (FRDM) in describing the $\alpha$ decay energies of the 947 known heavy and superheavy nuclei is studied. It is clearly found that there are obvious discrepancies between the $\alpha$ decay energies obtained by FRDM and those reported by the evaluated atomic mass table AME 2020 (AME), in particular that FRDM underestimates the experimental $\alpha$ decay energies of the superheavy nuclei. The $\alpha$ decay energies of known nuclei obtained by FRDM are optimized, i.e. FRDM-NN, using a neural network approach and the accuracy is significantly improved. The $\alpha$ decay energy systematics obtained by both FRDM and FRDM-NN show the obvious shell effect at neutron number $N=184$, implying that the $N=184$ may be the magic number of the superheavy nucleus region. The $\alpha$ decay half-lives of known superheavy nuclei are calculated using the Generalized Liquid Drop Model (GLDM) and the Royer formula with the input of the optimized $\alpha$ decay energies obtained by FRDM-NN, and the calculations can reproduce the experimental data well. The $\alpha$ decay half-lives of unknown superheavy nuclei, in particular superheavy nuclei with $Z=119$ and 120, are predicted by using the GLDM and the Royer formula with the input of the $\alpha$ decay energy obtained by FRDM-NN. The relative error of two types of predicted $\alpha$ decay half-lives and superposition are analysed, and the average predictions are given. The $\alpha$ decay energies predicted by FRDM-NN and the $\alpha$ decay half-lives calculated by the GLDM and the Royer formula can provide a reference for the experimental synthesis of new superheavy elements with $Z=119$ and 120.

Although tetraquarks and pentaquarks[1]were predicted along with the quark model in 1964,more than half a century passed,multiquark-like states observed in experiments are still rare.Among these states,the structure of hardly any was identified;whether they are multiquarks,molecules of hadrons,or other pos-sible species of resonances are still under debate(for a review,see e.g.,Refs.[2,3]). In 2020,a resonance of J/ψ pair around 6.9 GeV,X(6900),is observed by LHCb[4],and confirmed by the ATLAS[5]and CMS[6]Collaborations.In addition,a new resonance at around 6.6 GeV(we call it X(6600)in the rest of the paper)and evidence at around 7.2 GeV are also observed,and a lower state around 6.2 GeV(X(6200)),according to Ref.[7],was indicated by the data.All these states could be either tetraquarks(cc(c)(c))or states consist-ing of two hidden-charm mesons bound with screened strong forces.

A novel method was developed to detect double-A hypernuclear events in nuclear emulsions using machine learning techniques. The object detection model, the Mask R-CNN, was trained using images generated by Monte Carlo simulations, image processing, and image-style transformation based on generative adversarial networks. Despite being exclusively trained on AA6He events, the model achieved a detection efficiency of 93.8% for 6 AAHe and 82.0% for AA5H events in the produced images. In addition, the model demonstrated its ability to detect the 6 AAHe event named the Nagara event, which is the only uniquely identified double-A hypernuclear event reported to date. It also exhibited a proper segmentation of the event topology. Furthermore, after analyzing 0.2% of the entire emulsion data from the J-PARC E07 experiment utilizing the developed approach, six new candidates for double-A hypernuclear events were detected, suggesting that more than 2000 double- strangeness hypernuclear events were recorded in the entire dataset. This method is sufficiently effective for mining more latent double-A hypernuclear events recorded in nuclear emulsion sheets, significantly reducing the time required for manual visual inspection by a factor of five hundred.

The study of uranium isotopes plays a crucial role in advancing our knowledge of nuclear physics, particularly in the realm of isospin and exotic nuclei. This study focused on the ground-state properties of uranium isotopes ranging from A = 203 to A = 305. The key physical quantities examined included binding energy, quadrupole deformation, isotopic displacement, single-particle energy levels, and nucleon density distributions. Recent experimental advancements in uranium isotope studies have emphasized the indispensable role of theoretical models in interpreting experimental data. Moreover, the industrial applications of uranium—especially in nuclear energy production and weapons development—underscore the importance and necessity of accurate theoretical insights. The framework of the finite-range droplet model (FRDM) was utilized for comparative analysis because its predictions closely align with the experimental results. Through an analysis of the single-particle energy levels and continuous-state occupancy, this study identified ^207 U as the proton drip line nucleus. This research not only deepens our understanding of uranium isotopes but also provides a solid theoretical foundation to guide future experimental investigations.

The heavy-ion accelerator facility(HIAF)under construction in China will produce various stable and intense radioactive beams with energies ranging from MeV/u to GeV/u.The ion-linac(iLinac)accelerator,which will serve as the injector for the HIAF,is a superconducting heavy-ion accelerator containing 13 cryomodules.It will operate in either continuous wave mode or pulsed mode,with a beam current ranging from 0.01 to 1 emA.The beam position monitor(BPM)is crucial for this high-beam-power machine,which requires precise beam control and a very small beam loss of less than 1 W/m,especially inside the cryomodules of this unique beam instrument.Nearly 70 BPMs will be installed on the iLinac.New digital beam position and phase measurement(DBPPM)electronics based on a heterogeneous multiprocessing platform system-on-chip(MPSoC)has been developed to provide accurate beam trajectory and phase measurements as well as beam interlocking signals for a fast machine protection system(MPS).The DBPPM comprises an analog front-end(AFE)board in field pro-grammable gate array(FPGA)mezzanine-connector(FMC)form factor,along with a digital signal processing board housed within a 2U 19"chassis.To mitigate radio frequency(RF)leakage effects from high-power RF systems in certain scenarios,beam signals undergo simultaneous processing at both fundamental and second-harmonic frequencies.A dynamic range from-65 dBm to 0 dBm was established to accommodate both weak beam commissioning and high-intensity operational demands.Laboratory tests demonstrated that at input power levels exceeding-45 dBm,the phase resolution surpasses 0.05°,and the position resolution exceeds 5 μm.These results align well with the stipulated measurement requirements.Moreover,the newly developed DBPPM has self-testing and self-calibration functions that are highly helpful for the systematic evalu-ation of numerous electronic components and fault diagnosis equipment.In addition,the DBPPM electronics implements a 2D nonlinear polynomial correction on the FPGA and can collect accurate real-time position measurements at large beam offsets.This newly developed DBPPM electronics has been applied to several Linac machines,and the results from beam measurements show high performance,good long-term stability,and high reliability.In this paper,a detailed overview of the architecture,performance,and proof-of-principle measurement of the beams is presented.

A series of findings in machine learning (ML) and decay theory are captured while exploring the role of deformation and preformation factors in α decay. We provide a novel and practical paradigm for developing physics-driven machine learning in nuclear physics research by introducing known decay theory and statistical correlation analysis. Furthermore, this analysis verifies the Geiger-Nuttall law, and the relationship between the decay energy and α formation amplitude, also releases a signal that nuclei with hexadecapole deformation are more likely to form α clusters. In particular, we identify two novel phenomena, shape inheritance, in which the deformation properties are partially transmitted from parent to daughter nuclei; and half-life inversion due to shape staggering of adjacent even-even nuclei. This phenomenon occurs frequently in neutron-deficient nuclei near lead isotopes, which is consistent with shape coexistence in experiments. Surprisingly, it reappeared within the predicted half-life of the 119 and 120 isotope chains in the eighth period of the periodic table. The half-life considering the inversion effect is preferable for the study of new nuclides and shape coexistence in experiments.

This paper provides a comprehensive analysis of all stages of the heavy-ion fusion evaporation reaction, aiming to enhance the understanding of the entire process and identify the influencing factors in calculating the evaporation residue cross-section. By focusing on the synthesis of superheavy nuclei with Z=114 , we discuss the capture cross-section, fusion probability, and survival probability of the 48Ca+244Pu reaction and compare them with those of the 40Ar+248Cm reaction. Moreover, a systematic study examined the evaporation residue cross-sections for the synthesis of superheavy nuclei with Z=112-116 using 40Ar as the projectile nucleus. The results indicate that utilizing 40Ar as the projectile nucleus for synthesizing isotopes with Z=114 offers advantages such as lower incident energy and reduced experimental costs. Furthermore, using 40Ar as the projectile nucleus enables the synthesis of a new key isotope, 285115, thereby facilitating its identification.

Two-proton (2p) radioactivity constitutes a pivotal probe for studying the nuclear structure of extreme proton-rich nuclei. To improve the calculated accuracy and predictive power of the generalized liquid drop model (GLDM) for describing the 2p radioactivity half-lives, this work performs a systematic study within the GLDM framework using distinct proximity energies. It is found that the proximity energy can counterbalance the Coulomb repulsion, lowering the barrier height and simultaneously shifting its peak to larger radial separations. Consequently, the specific proximity energy employed governs both the height and shape of the interaction barrier, thereby dictating the penetration probability, and ultimately, the 2p radioactivity half-life. Among all considered proximity energy formalisms, the Prox. 77-Set 13 yields the smallest standard deviation when reproducing experimental data for known true 2p emitters, representing an improvement over the original proximity potential. The spectroscopic factor of 2p radioactivity S2p is found to be essential for reducing systematic deviations. Using the GLDM with Prox. 77-Set 13, we predict 2p radioactivity half-lives for candidate nuclei. The predictions agree well with those from other established models and validate the newly proposed Geiger-Nuttall law for 2p radioactivity. This work would provide reference for future experimental investigations of 2p radioactivity in proton-rich nuclei.

Synthesis of new elements with Z ≥ 119 is currently a forefront issue in modern nuclear physics. The central question then arises as to the stability and decay properties of these new elements. In this study, the competition between α -decay, spontaneous fission, cluster radioactivity, and β -decay in the isotopic chains of Z=119 and Z=120 was investigated using the finite-range droplet model (FRDM) and Weizsäcker -Skyrme model (WS4). The Royer formula, Karpov formula, Universal Decay Law, and Sobhani formula were applied to analyze each respective decay mode. It was found that cluster radioactivity and β -decay is at a disadvantage in these isotopic chains, with α -decay and SF being the dominant decay modes. For nuclei with longer half-lives for the dominant decay modes, α -decay tends to be the most prevalent. N=184 is a candidate for the neutron magic number based on WS4 and FRDM. In addition, the generalized liquid drop model with corrections for surface diffuseness effects was employed to study α -decay across four different sets of mass models: FRDM, WS4, Koura–Tachibana–Uno–Yamada (KTUY) mass formula, and Niu2022. The calculation of α -decay half-lives was further optimized through the use of the radial basis function network.

Cluster radioactivity is studied within the generalized liquid drop model (GLDM), in which the shell correction energy, pairing energy, and cluster preformation factor are considered. The calculations show significant improvements and can reproduce the experimental data within a factor of 8.04 after considering these physical effects. In addition, the systematic trend of the cluster preformation factors P-c is discussed in terms of the NpNn scheme to study the influence of the valence proton-neutron interaction and shell effect on cluster radioactivity. It is found that log(10) P-c is linearly related to NpNn. This is in agreement with a recent study [L. Qi et al., Phys. Rev. C 108, 014325 (2023)], in which log(10) P-c, obtained using different theoretical models and treatment methods than those used in this study, also had a linear relationship with NpNn. Combined with the work by Qi et al., this study suggests that the linear relationship between log(10) P-c and NpNn is model-independent and both the shell effect and valence proton-neutron interaction play essential roles in cluster radioactivity. An analytical formula is proposed to calculate the cluster preformation factor based on the NpNn scheme. In addition, the cluster preformation factors and the cluster radioactivity half-lives of some heavy nuclei are predicted, which can provide a reference for future experiments.

The synthesis of superheavy elements represents the forefront of exploring the properties of unknown nuclear matter. Theoretically, significant uncertainties in predicting the fission barriers of superheavy nuclei make accurate calculations of the survival probabilities of compound nuclei extremely challenging. This study utilizes a machine learning methodology to predict the fission barriers of nuclides with 93<Z <= 120 and 135<N <= 184. We have estimated the fission barriers for a total of 660 nuclides, and leveraged these fission barriers to calculate the crucial survival probabilities in the synthesis of superheavy elements. Based on this, we calculated the reaction cross sections for the Ca-48+Am-243 reaction within the framework of the dinuclear system model, and compared the results with experimental data measured using the new gas-filled separator DGFRS-2. The calculations successfully reproduced the experimental data within an acceptable range of error. Additionally, we explored the optimal synthesis conditions for synthesizing the new elements Z=119 and Z=120, including projectile-target combinations, incident energies, and maximum reaction cross sections.

A novel method was developed to detect double-Λ hypernuclear events in nuclear emulsions using machine learning techniques. The object detection model, the Mask R-CNN, was trained using images generated by Monte Carlo simulations, image processing, and image-style transformation based on generative adversarial networks. Despite being exclusively trained on 6 ΛΛHe events, the model achieved a detection efficiency of 93.9% for 6 ΛΛHe and 81.5% for 5 ΛΛH events in the produced images. In addition, the model demonstrated its ability to detect the Nagara event, which is the only uniquely identified 6ΛΛHe event reported to date. It also exhibited a proper segmentation of the event topology. Furthermore, after analyzing 0.2% of the entire emulsion data from the J-PARC E07 experiment utilizing the developed approach, six new candidates for double-Λ hypernuclear events were detected, suggesting that more than 2000 double-strangeness hypernuclear events were recorded in the entire dataset. This method is sufficiently effective for mining more latent double-Λ hypernuclear events recorded in nuclear emulsion sheets by reducing the time required for manual visual inspection by a factor of five hundred.

The synthesis of new nuclides is an important direction in nuclear physics research. This article explores the optimal methods for producing new nuclides in the transuranic nuclear region. Based on the dinuclear system model, the influence of the isospin effect on the synthesis of actinide neutron-deficient nuclides through fusion evaporation reactions is studied. It is found that, for the same compound nucleus, using projectile-target combinations with a smaller neutron asymmetry can result in a larger capture cross section. Subsequently, taking the synthesis of curium element isotopes as an example, the best method for producing new actinide nuclides is explored. It is found that fusion evaporation reactions can achieve a larger reaction cross section under extremely neutron-deficient conditions, while multinucleon transfer reactions have a larger cross section in the neutron-rich region. Finally, the possibility of producing superheavy neutron-rich nuclides using multinucleon transfer reactions is theoretically predicted.

The investigation of the equation of state(EoS)of nuclear matter,especially at high baryon densities is one of the hot topics in the frontier of nuclear physics.The impact of the EoS at 2～5 times saturation density ρ0 on the two-particle cor-relation is discussed with the ultra-relativistic quantum molecular dynamics(UrQMD)model.Focusing on the two π Hanbury-Brown-Twiss(HBT)correlations,by adopting different EoSs,the effects of potential interaction and phase transition on the HBT correlation and the spatiotemporal properties of the emission source of π are investigated.The results show that below～5ρ0,the HBT radius and parameters are sensitive to the stiffness of the EoS.By comparing with the experiment data,first-order phase transition with a significant softening of the equation of state below 4 times nuclear saturation density can be ex-cluded using HBT data,and the available data on the HBT radii in the investigated energy region favor a relatively stiff EoS at low densities,which then turns into a soft EoS at high densities.These results highlight that the pion's HBT radius and para-meters are sensitive to the stiffness of the equation of state,and can be used to constrain and understand the equation of state in the high baryon density region.