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Theoretical study on favored alpha-decay half-lives of deformed nuclei
M. Hassanzad, O.N. Ghodsi
Published:   , doi: 10.1088/1674-1137/ac28f3
A systematic study on α-decay half-lives for the nuclei in the range \begin{document}$93\leqslant Z \leqslant 118$\end{document} is done by employing various versions of proximity potentials. To obtain the more reliable results, the deformation terms are included up to hexadecapole (\begin{document}$\beta_{4}$\end{document}) in the spherical-deformed nuclear and Coulomb interaction potentials. The favored α-decays process in this region are categorized as the even-even, odd A, and odd-odd nuclei, first, and second they are grouped into two parts as a ground state to ground state and ground state to isomeric states transition. Due to their root-mean-square deviations (RMSD's) comparison, \begin{document}$Bass 77$\end{document} and \begin{document}$Ngo 80$\end{document} have the least values and better compromise in reproducing experimental data. Besides, by considering preformation probability within the cluster formation model, the results validate that the significant reduction in root-mean-square deviations has been obtained for different versions of proximity; Hence detract the deviation between calculated and experimental data.
Probing the anisotropic distribution of baryon matter in the Universe using fast radio bursts
Hai-Nan Lin, Yu Sang
Published:   , doi: 10.1088/1674-1137/ac2660
We propose that fast radio bursts (FRBs) can be used as the probes to constrain the possible anisotropic distribution of baryon matter in the Universe. Monte Carlo simulations show that, 400 (800) FRBs are enough to detect the anisotropy at 95% (99%) confidence level, if the dipole amplitude is at the order of magnitude 0.01. However, much more FRBs are required to tightly constrain the dipole direction. Even 1000 FRBs are far from enough to constrain the dipole direction within angular uncertainty \begin{document}$\Delta\theta<40^{\circ}$\end{document} at 95% confidence level. The uncertainty on the dispersion measure of host galaxy does not significantly affect the results. If the dipole amplitude is in the level of 0.001, however, 1000 FRBs are not enough to correctly detect the anisotropic signal.
Measurements of natCd(γ, x) reaction cross-sections and isomer ratio of 115m,gCd with the bremsstrahlung end-point energies of 50- and 60-MeV
Muhammad Nadeem, Md. Shakilur Rahman, Muhammad Shahid, Guinyun Kim, Haladhara Naik, Nguyen Thi Hien
Published:   , doi: 10.1088/1674-1137/ac256b
The flux-weighted average cross sections of natCd(γ, xn)115g,m,111m,109,107,105,104Cd and natCd(γ, x)113g,112,111g,110mAg reactions were measured at the bremsstrahlung end-point energies of 50 and 60 MeV with the activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The natCd(γ, xn) reaction cross sections as a function of photon energy were theoretically calculated using the TALYS-1.95 and the EMPIRE-3.2 malata codes. Then the flux-weighted average cross sections were obtained from the theoretical values of mono-energetic photons. These values were compared with the flux-weighted values of the present work and are found to be in general agreement. The measured experimental reaction cross-sections and integral yields are described for cadmium and silver isotopes in the natCd(γ, xn)115g,m,111m,109,107,105,104Cd and natCd(γ, x)113g,112,111g,110mAg reactions. The isomeric yield ratio (IR) of 115g,mCd in the natCd(γ, xn) reaction was also determined for above two bremsstrahlung end-point energies. The measured isomeric yield ratios of 115g,mCd in the natCd(γ, xn) reaction were also compared with the theoretical values of the nuclear model codes and the earlier published literature data in the 116Cd(γ,n) and 116Cd(n,2n) reactions. It was found that with the increase of projectile energy IR value increases, which demonstrate the characteristic of excitation energy. However, the higher IR value of 115g,mCd in the 116Cd(n,2n) reaction compared to the 116Cd(γ,n) reaction indicates the role of compound nuclear spin besides excitation energy.
Effect of non-uniform efficiency on higher-order cumulants in heavy-ion collisions
Fan Si, Yifei Zhang, Xiaofeng Luo
Published:   , doi: 10.1088/1674-1137/ac24f6
We perform a systematic study on the effect of non-uniform track efficiency correction in higher-order cumulant analysis in heavy-ion collisions. Through analytical derivation, we find that the true values of cumulants can be successfully reproduced by the efficiency correction with an average of the realistic detector efficiency for particles with the same charges within each single phase space. During a toy model simulation by tuning the non-uniformity of the efficiency employed in the track-by-track efficiency correction method, the theoretical conclusions are supported and the valid averaged efficiency is found to suppress the statistical uncertainties of the reproduced cumulants dramatically. Thus, the usage of the averaged efficiency requires a careful study for the phase space dependence. This study is important for carrying out precision measurements of higher-order cumulants in heavy-ion collision experiments at present and in future.
Scalar-pseudoscalar pair production at the Large Hadron Collider at NLO+NLL accuracy in QCD
He-Yi Li, Ren-You Zhang, Yu Zhang, Wen-Gan Ma, Ming-Ming Long, Shu-Xiang Li
Published:   , doi: 10.1088/1674-1137/ac23d2
We investigate in detail both transverse momentum and threshold resummation effects on the scalar-pseudoscalar pair production via quark-antiquark annihilation at the \begin{document}$ 13 \; \text{TeV}$\end{document} Large Hadron Collider at the QCD NLO+NLL accuracy. A factorization method is introduced to supplement properly the soft-gluon (threshold) resummation contribution from parton distribution functions to the resummed results obtained by the Collins-Soper-Sterman resummation approach. We find that the impact of the threshold-resummation improved PDFs is comparable to the resummation effect from the partonic matrix element and can even predominate in high invariant mass region. Moreover, the loop-induced gluon-gluon fusion channel in the type-I two-Higgs-doublet model is also taken into account in our calculation. Our numerical results show that the electroweak production via quark-antiquark annihilation dominates over the gluon-initiated QCD production by \begin{document}$ 1 \sim 2$\end{document} orders of magnitude.
Two-proton radioactivity of ground and excited states within a unified fission model
Fengzhu Xing, Jianpo Cui, Yanzhao Wang, Jianzhong Gu
Published:   , doi: 10.1088/1674-1137/ac2425
Firstly, a unified fission model is extended to study the two-proton radioactivity of ground states of nuclei, a good agreement between the experimental half-lives and the calculated ones is found. Meanwhile, the two-proton radioactivity half-lives of the ground states of some probable candidates are predicted within this model by inputting the released energies taken from the AME2020 table. It is shown that the predictive accuracy of the half-lives is comparable to that of other models. Then, the two-proton radioactivity of the excited states of 14O, 17,18Ne, 22Mg, 29S and 94Ag is discussed within the unified fission model and two analytical formulas. It is found that the experimental half-lives of the excited states are reproduced better within the unified fission model. Furthermore, the two formulas are not suitable for the study of the two-proton radioactivity of excited states because not only their physical picture deviates from the mechanism of a quantum tunneling but also the parameters involved are obtained without including the experimental data of the excited states.
Systematic study of two-proton radioactivity half-lives within the two-potential approach with Skyrme-Hartree-Fock
Xiao Pan, You-Tian Zou, Hong-Ming Liu, Biao He, Xiao-Hua Li, Xi-Jun Wu, Zhen Zhang
Published:   , doi: 10.1088/1674-1137/ac2421
In this work, we systematically study the two-proton(\begin{document}$2p$\end{document}) radioactivity half-lives using the two-potential approach while the nuclear potential is obtained by using Skyrme-Hartree-Fock approach with the Skyrme effective interaction of SLy8. For true \begin{document}$2p$\end{document} radioactivity(\begin{document}$Q_{2p}$\end{document} \begin{document}$>$\end{document} 0 and \begin{document}$Q_p$\end{document} \begin{document}$< $\end{document}0, where the \begin{document}$Q_p$\end{document} and \begin{document}$Q_{2p}$\end{document} are the released energy of the one-proton and two-proton radioactivity), the standard deviation between the experimental half-lives and our theoretical calculations is 0.701. In addition, we extend this model to predict the half-lives of 15 possible \begin{document}$2p$\end{document} radioactivity candidates with \begin{document}$Q_{2p}$\end{document} \begin{document}$>$\end{document} 0 taken from the evaluated atomic mass table AME2016. The calculated results indicate that a clear linear relationship between the logarithmic \begin{document}$2p$\end{document} radioactivity half-lives \begin{document}$\rm{log}_{10}T_{1/2}$\end{document} and coulomb parameters [ (\begin{document}$Z_{d}^{0.8}$\end{document}+\begin{document}${l}^{\,0.25}$\end{document})\begin{document}$Q_{2p}^{-1/2}$\end{document}] considered the effect of orbital angular momentum proposed by Liu \begin{document}$et$\end{document} \begin{document}$al$\end{document} [Chin. Phys. C 45, 024108 (2021)] is also existed. For comparison, the generalized liquid drop model(GLDM), the effective liquid drop model(ELDM) and Gamow-like model are also used. Our predicted results are consistent with the ones obtained by the other models.
Survey of deep sub-barrier heavy-ion fusion hindrance phenomenon for positive and negative Q-value systems using the proximity-type potential
R. Gharaei, A. Fuji, B. Azadegan
Published:   , doi: 10.1088/1674-1137/ac23d3
A systematic survey of the accurate measurements of heavy-ion fusion cross sections at extreme sub-barrier energies has been carried out by using the coupled-channels (CC) theory that is based on the proximity formalism. The present work theoretically explores the role of surface energy coefficient and energy-dependent nucleus-nucleus proximity potential in mechanism of the fusion hindrance of 14 typical colliding systems with negative \begin{document}$Q$\end{document}-values, including 11B+197Au, 12C+198Pt, 16O+208Pb, 28Si+94Mo, 48Ca+96Zr, 28Si+64Ni, 58Ni+58Ni, 60Ni+89Y, 12C+204Pb, 36S+64Ni, 36S+90Zr, 40Ca+90Zr, 40Ca+40Ca and 48Ca+48Ca as well as 5 typical colliding systems with positive \begin{document}$Q$\end{document}-values, including 12C+30Si, 24Mg+30Si, 28Si+30Si, 36S+48Ca, and 40Ca+48Ca. It is shown that the outcomes based on the proximity potential along with the above-mentioned physical effects are able to achieve reasonable agreement with the experimentally observed data of the fusion cross sections \begin{document}$\sigma_{\rm{fus}}(E)$\end{document}, astrophysical \begin{document}$S(E)$\end{document} factors, and logarithmic derivatives \begin{document}$L(E)$\end{document} in the energy region far below the Coulomb barrier. A discussion is also presented about the performance of the present theoretical approach in reproducing the experimental fusion barrier distributions for different colliding systems.
Modeling complex networks of nuclear reaction data for probing their discovery processes
Xiaohang Wang, Long Zhu, Jun Su
Published:   , doi: 10.1088/1674-1137/ac23d5
Experimental data sets of nuclear reactions have been systematically collected in hundreds of thousands and are still growing rapidly. The data and their correlations compose a complex system, which underpins nuclear science and technology. We model the nuclear reaction data as weighted evolving networks for the purpose of data verification and validation. The networks are employed to study the growing cross-section data of a neutron induced threshold reaction (n,2n) and photoneutron reaction. In the networks, nodes are the historical data and weights of the links are the relative deviation between the data points. It is found that the networks exhibit the small-world behavior, and their discovery processes are well described by the Heaps law. What makes the networks novel is the mapping relation between the network properties and the salient features of the database: Heaps exponent corresponds to the exploration efficiency of the specific data set, the distribution of the edge-weights corresponds to the global uncertainty of the data set, and the mean node weight corresponds to the uncertainty of the individual data point. This new perspective to understand the database would be helpful for nuclear data analysis and compilation.
Semi-inclusive lepto-production of hidden-charm exotic hadrons
Zhi Yang, Feng-Kun Guo
Published:   , doi: 10.1088/1674-1137/ac2359
We investigate the semi-inclusive production of hidden-charm exotic states, including \begin{document}$X(3872)$\end{document}, \begin{document}$Z_c$\end{document}, \begin{document}$Z_{cs}$\end{document} and the pentaquark \begin{document}$P_c$\end{document} states, in lepton-proton scattering processes. These hadrons are close to the thresholds of a pair of charm and anticharm hadrons, and are assumed to have hadronic molecular structure as their main components. In order to give order-of-magnitude estimates of the cross sections, we use Pythia to simulate the short-distance productions of the constituent hadrons, which then rescatter to form the exotic hadrons. The estimates for the \begin{document}$X(3872)$\end{document} and \begin{document}$Z_c(3900)^\pm$\end{document} are not in conflict with the upper limits measured at the COMPASS experiment for the exclusive photoproduction process. The results here indicate that the considered hidden-charm states can be copiously produced at the proposed electron-ion colliders EicC and US-EIC.
Evaluation of pre-neutron-emission mass distributions of neutron-induced typical actinide fission by scission point model
Dong-Ying Huo, Xu Yang, Chao Han, Chang-Qi Liu, Kang Wu, Xing-Yu Liu, Chang Huang, Qin Xie, Yuan He, Xiao-Jun Bao, Ze-En Yao, Yu Zhang, Jun-Run Wang, Xiao-Dong Su, Zheng Wei
Published:   , doi: 10.1088/1674-1137/ac2298
The scission point model is improved by considering the excitation-dependent liquid drop model to calculate mass distributions for neutron-induced actinide nuclei fission. Excitation energy effects are influencing the deformations of light fragment and heavy fragment. The improved scission point model shows a significant advance with regard to accuracy for calculating pre-neutron-emission mass distributions of neutron-induced typical actinide fission with incident-neutron-energies up to 99.5 MeV. The theoretical frame assures that the improved scission point model is suitable for evaluating of the fission fragments mass distributions, which will guide for studying the fission physics, designing nuclear fission engineering and nuclear transmutation system.
Higher-twist corrections to $D\to\pi,K$ form factors from light-cone sum rules
Long-Sheng Lu, Yong-Kang Huang, Xuan-Heng Zhang
We calculate the \begin{document}$D\to P$\end{document} transition form factors within the framework of the light-cone QCD sum rules (LCSR) with the D-meson light-cone distribution amplitudes (LCDAs). The next-to-leading power (NLP) corrections to the vacuum-to-D-meson correlation function are considered, and the NLP corrections from the high-twist D-meson LCDAs and the SU(3) breaking effect from strange quark mass are investigated. Adopting the exponential model of the D-meson LCDAs, the predicted SU(3) flavor symmetry breaking effects are \begin{document}$R_{SU(3)}.{+,0}=1.12$\end{document} and \begin{document}$R_{SU(3)}.{T}=1.39$\end{document}, respectively, which confirms the results from LCSR with pion LCDA. The numerical predictions of the form factors show that the contribution from two-particle higher-twist contributions is of great importance and the uncertainties are dominated by the inverse moment of \begin{document}$\phi_D.+(\omega, \mu)$\end{document}. With the obtained form factors, the predicted Cabibbo-Kobayashi-Maskawa (CKM) matrix elements are \begin{document}$|V_{cd}|=0.151\,{}.{+0.091}_{-0.043} \big |_{\rm th.}\,{}.{+0.017}_{-0.02} \big |_{\rm exp.}$\end{document} and \begin{document}$|V_{cs}|=0.89\,{}.{+0.467}_{-0.234} \big |_{\rm th.}\,{}.{+0.008}_{-0.008} \big |_{\rm exp.}$\end{document}.
Production of light-flavor and single-charmed hadrons in pp collisions at ${ \sqrt{\boldsymbol s} = {\bf 5.02 }}$ TeV in an equal-velocity quark combination model
Hai-hong Li, Feng-lan Shao, Jun Song
We apply an equal-velocity quark combination model to study the production of light-flavor hadrons and single-charmed hadrons at midrapidity in \begin{document}$ pp $\end{document} collisions at \begin{document}$ \sqrt{s} = 5.02 $\end{document} TeV. We find experimental data for \begin{document}$ p_{T} $\end{document} spectra of \begin{document}$ \Omega $\end{document} and \begin{document}$ \phi $\end{document} exhibit a quark number scaling property, which is a clear signal of quark combination mechanism at hadronization. Experimental data for \begin{document}$ p_T $\end{document} spectra of \begin{document}$ p $\end{document}, \begin{document}$ \Lambda $\end{document}, \begin{document}$ \Xi $\end{document}, \begin{document}$ \Omega $\end{document}, \begin{document}$ \phi $\end{document} and \begin{document}$ K^{*0} $\end{document} are systematically described by the model. The non-monotonic \begin{document}$ p_{T} $\end{document} dependence of \begin{document}$ \Omega/\phi $\end{document} ratio is naturally explained and we find it is closely related to the shape of the logarithm of strange quark \begin{document}$ p_{T} $\end{document} distribution. Using \begin{document}$ p_{T} $\end{document} spectra of light-flavor quarks obtained from light-flavor hadrons and a \begin{document}$ p_T $\end{document} spectrum of charm quarks which is consistent with perturbative QCD calculations, the experimental data for differential cross-sections of \begin{document}$ D^{0,+} $\end{document}, \begin{document}$ D_{s}^{+} $\end{document} and \begin{document}$ \Lambda_{c}^{+} $\end{document} as the function of \begin{document}$ p_{T} $\end{document} are systematically described. We predict the differential cross-sections of \begin{document}$ \Xi_{c}^{0,+} $\end{document} and \begin{document}$ \Omega_{c}^{0} $\end{document}. The ratio \begin{document}$ \Xi_{c}^{0,+}/D^{0} $\end{document} in our model is about 0.16 and \begin{document}$ \Omega_{c}^{0}/D^{0} $\end{document} is about 0.012 due to the cascade suppression of strangeness. In addition, the predicted \begin{document}$ \Xi_{c}^{0,+}/D^{0} $\end{document} and \begin{document}$ \Omega_{c}^{0}/D^{0} $\end{document} ratios exhibit the non-monotonic dependence on \begin{document}$ p_{T} $\end{document} in the low \begin{document}$ p_{T} $\end{document} range.