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Published:   , doi: 10.1088/1674-1137/ac256b
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac24f6
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac23d2
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac2425
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac2421
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac23d3
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac23d4
Abstract:
In the framework of the relativistic mean field theory combined with the complex momentum representation method, we study in detail the pseudospin symmetry in the single-neutron resonant states and its dependence on \begin{document}$\sigma$\end{document}, \begin{document}$\omega$\end{document} and \begin{document}$\rho$\end{document} meson fields. Compared with the effect of the \begin{document}$\rho$\end{document} field, the \begin{document}$\sigma$\end{document} and \begin{document}$\omega$\end{document} fields gives the main contribution to the pseudospin energy and width splitting of the resonant pseudospin doublets. Especially, we compare quantitatively the pseudospin wave functions splittings in resonant doublets, and investigate their dependencies on different fields of mesons, which is consistent with that of energy and width splittings. The present researches are helpful to understand the mechanism and properties of pseudospin symmetry for resonant states.
Published:   , doi: 10.1088/1674-1137/ac23d5
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac2359
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac2298
Abstract:
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.
Published:   , doi: 10.1088/1674-1137/ac224b
Abstract:
The strong coupling constants are basic quantities that carry information of the strong interactions among the baryon and meson multiplets as well as information on the natures and internal structures of the involved hadrons. These parameters enter to the transition matrix elements of various decays as main inputs and they play key roles in analyses of the experimental data including various hadrons. We determine the strong coupling constants among the doubly heavy spin-\begin{document}$3/2$\end{document} baryons, \begin{document}$\Xi^*_{QQ'}$\end{document} and \begin{document}$\Omega^*_{QQ'}$\end{document}, and light pseudoscalar mesons, π, K and η, using the light-cone QCD. The values obtained for the strong coupling constants under study may be used in construction of the strong potentials among the doubly heavy spin-3/2 baryons and light pseudoscalar mesons.
Published:
Abstract:
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}.
Published:
Abstract:
Understanding the thermodynamic phase transition of black holes can provide the deep insight into the fundamental properties of black hole gravity to establish the theory of quantum gravity. In this work, we investigate the condition and latent heat of phase transition for the non-linear charged AdS black holes by the Maxwell's equal-area law, and analysis the boundary and curve of two-phase coexistence area in the expanded phase space. We suggest that the phase transition of the non-linear charged AdS black hole with the fixed temperature (\begin{document}$T<T_c$\end{document}) is related with the electric potential at the horizon, not only with the location of horizon. Recently, the introduction of the molecular number density is to study the phase transition and microstructure of black hole. On this basis, we discuss the continuous phase transition of the non-linear charged AdS black hole to reveal the maybe microstructure of black hole by introducing the order parameter and using the scalar curvature.
Published:
Abstract:
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.