Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>The potential-driving model is used to describe the driving potential distribution and to calculate the pre-neutron emission mass distributions for different incident energies in the <jats:inline-formula> <jats:tex-math><?CDATA $ {}^{237} \rm{Np(n,f)} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064001_M1.jpg" xlink:type="simple" /> </jats:inline-formula> reaction. The potential-driving model is implemented in Geant4 and used to calculate the fission-fragment yield distributions, kinetic energy distributions, fission neutron spectrum and the total nubar for the <jats:inline-formula> <jats:tex-math><?CDATA $ {}^{237} \rm{Np(n,f)} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064001_M2.jpg" xlink:type="simple" /> </jats:inline-formula> reaction. Compared with the built-in G4ParaFissionModel, the calculated results from the potential-driving model are in better agreement with the experimental data and evaluated data. Given the good agreement with the experimental data, the potential-driving model in Geant4 can describe well the neutron-induced fission of actinide nuclei, which is very important for the study of neutron transmutation physics and the design of a transmutation system. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The Faddeev AGS equations for the coupled-channels <jats:inline-formula> <jats:tex-math><?CDATA $\bar{K}NN-\pi\Sigma{N}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M2.jpg" xlink:type="simple" /> </jats:inline-formula> system with quantum numbers <jats:italic>I</jats:italic>= 1/2 and <jats:italic>S</jats:italic>= 0 are solved. Using separable potentials for the <jats:inline-formula> <jats:tex-math><?CDATA $\bar{K}N-\pi\Sigma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M3.jpg" xlink:type="simple" /> </jats:inline-formula> interaction, we calculate the transition probability for the <jats:inline-formula> <jats:tex-math><?CDATA $(Y_{K})_{I=0}+N\rightarrow\pi\Sigma{N}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M4.jpg" xlink:type="simple" /> </jats:inline-formula> reaction. The possibility to observe the trace of the <jats:inline-formula> <jats:tex-math><?CDATA $K^{-}pp$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M5.jpg" xlink:type="simple" /> </jats:inline-formula> quasi-bound state in <jats:inline-formula> <jats:tex-math><?CDATA $\pi\Sigma{N}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M6.jpg" xlink:type="simple" /> </jats:inline-formula> mass spectra was studied. Various types of chiral-based and phenomenological potentials are used to describe the <jats:inline-formula> <jats:tex-math><?CDATA $\bar{K}N-\pi\Sigma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M7.jpg" xlink:type="simple" /> </jats:inline-formula> interaction. Finally, we show that we can observe the signature of the <jats:inline-formula> <jats:tex-math><?CDATA $K^{-}pp$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064101_M8.jpg" xlink:type="simple" /> </jats:inline-formula> quasi-bound state in the mass spectra, as well as the trace of branch points in the observables. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The Efimov (Thomas) trimers in excited <jats:sup>12</jats:sup>C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of <jats:sup>70(64)</jats:sup>Zn(<jats:sup>64</jats:sup>Ni) + <jats:sup>70(64)</jats:sup>Zn(<jats:sup>64</jats:sup>Ni) reactions at the beam energy of E/A = 35 MeV/nucleon. In heavy ion collisions, <jats:inline-formula> <jats:tex-math><?CDATA $ \alpha $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064102_M7.jpg" xlink:type="simple" /> </jats:inline-formula>-particles interact with each other and can form complex systems such as <jats:sup>8</jats:sup>Be and <jats:sup>12</jats:sup>C. For the 3 <jats:inline-formula> <jats:tex-math><?CDATA $ \alpha $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064102_M10.jpg" xlink:type="simple" /> </jats:inline-formula>-particle systems, multi-resonance processes give rise to excited levels of <jats:sup>12</jats:sup>C. The interaction between any two of the 3 <jats:inline-formula> <jats:tex-math><?CDATA $ \alpha $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064102_M12.jpg" xlink:type="simple" /> </jats:inline-formula>-particles provides events with one, two or three <jats:sup>8</jats:sup>Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events with the three <jats:inline-formula> <jats:tex-math><?CDATA $ \alpha $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064102_M14.jpg" xlink:type="simple" /> </jats:inline-formula>-particle relative energies consistent with the ground state of <jats:sup>8</jats:sup>Be are observed with the decrease of the instrumental error for the reconstructed 7.458 MeV excitation level in <jats:sup>12</jats:sup>C, which was suggested as the Efimov (Thomas) state. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Significant enhancements of <jats:inline-formula> <jats:tex-math><?CDATA $ J/\psi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064103_M2.jpg" xlink:type="simple" /> </jats:inline-formula> production at very low transverse momenta were recently observed by the ALICE and STAR collaborations in peripheral hadronic A+A collisions. The anomalous excess points to coherent photon-nucleus interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. Assuming that the coherent photoproduction is the underlying mechanism responsible for the excess observed in peripheral A+A collisions, its contribution in p+p collisions with nuclear overlap, i.e. non-single-diffractive collisions, is of particular interest. In this paper, we perform a calculation of exclusive <jats:inline-formula> <jats:tex-math><?CDATA $ J/\psi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064103_M3.jpg" xlink:type="simple" /> </jats:inline-formula> photoproduction in non-single-diffractive p+p collisions at the RHIC and LHC energies based on the pQCD motivated parametrization using the world-wide experimental data, which could be further employed to improve the precision of the phenomenological calculations for photoproduction in A+A collisions. The differential rapidity and transverse momentum distributions of <jats:inline-formula> <jats:tex-math><?CDATA $ J/\psi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064103_M4.jpg" xlink:type="simple" /> </jats:inline-formula> from photoproduction are presented. In comparison with the <jats:inline-formula> <jats:tex-math><?CDATA $ J/\psi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064103_M5.jpg" xlink:type="simple" /> </jats:inline-formula> production from hadronic interactions, we find that the contribution of photoproduction is negligible. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Within an effective Lagrangian approach and resonance model, we study the <jats:inline-formula> <jats:tex-math><?CDATA $ \gamma p \to a_1(1260)^+ n $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M3.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ \gamma p \to \pi^+\pi^+\pi^- n $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M4.jpg" xlink:type="simple" /> </jats:inline-formula> reactions via the <jats:inline-formula> <jats:tex-math><?CDATA $ \pi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M5.jpg" xlink:type="simple" /> </jats:inline-formula>-exchange mechanism. For the <jats:inline-formula> <jats:tex-math><?CDATA $ \gamma p \to \pi^+\pi^+\pi^- n $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M6.jpg" xlink:type="simple" /> </jats:inline-formula> reaction, we perform a calculation of the differential and total cross-sections by considering the contributions of the <jats:inline-formula> <jats:tex-math><?CDATA $ a_1(1260) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M7-1.jpg" xlink:type="simple" /> </jats:inline-formula> intermediate resonance decaying into <jats:inline-formula> <jats:tex-math><?CDATA $ \rho \pi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M8.jpg" xlink:type="simple" /> </jats:inline-formula> and then into <jats:inline-formula> <jats:tex-math><?CDATA $ \pi^+\pi^+\pi^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M9.jpg" xlink:type="simple" /> </jats:inline-formula>. Besides, the non-resonance process is also considered. With a lower mass of <jats:inline-formula> <jats:tex-math><?CDATA $ a_1(1260) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M10.jpg" xlink:type="simple" /> </jats:inline-formula>, the experimental data for the invariant <jats:inline-formula> <jats:tex-math><?CDATA $ \pi^+\pi^+\pi^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M11.jpg" xlink:type="simple" /> </jats:inline-formula> mass distributions can be fairly well reproduced. For the <jats:inline-formula> <jats:tex-math><?CDATA $ \gamma p \to a_1(1260)^+ n $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M12.jpg" xlink:type="simple" /> </jats:inline-formula> reaction, with the model parameters, the total cross-section is of the order of 10 μb at the photon beam energy <jats:inline-formula> <jats:tex-math><?CDATA $ E_{\gamma} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064104_M14.jpg" xlink:type="simple" /> </jats:inline-formula>~2.5 GeV. It is expected that the model calculations in this work could be tested by future experiments. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The multinucleon transfer reaction in the collisions of <jats:sup>40</jats:sup>Ca+ <jats:sup>124</jats:sup>Sn at <jats:inline-formula> <jats:tex-math><?CDATA $ E_{ \rm{c.m.}}=128.5 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064105_M3.jpg" xlink:type="simple" /> </jats:inline-formula> MeV is investigated using the improved quantum molecular dynamics model. The measured angular distributions and isotopic distributions of the products are reproduced reasonably well by the calculations. The multinucleon transfer reactions of <jats:sup>40</jats:sup>Ca + <jats:sup>112</jats:sup>Sn, <jats:sup>58</jats:sup>Ni + <jats:sup>112</jats:sup>Sn, <jats:sup>106</jats:sup>Cd + <jats:sup>112</jats:sup>Sn, and <jats:sup>48</jats:sup>Ca + <jats:sup>112</jats:sup>Sn are also studied. This demonstrates that the combinations of neutron-deficient projectile and target are advantageous for the production of exotic neutron-deficient nuclei near <jats:italic>N</jats:italic>, <jats:italic>Z</jats:italic> = 50. The charged particles' emission plays an important role at small impact parameters in the de-excitation processes of the system. The production cross sections of the exotic neutron-deficient nuclei in multinucleon transfer reactions are much larger than those measured in the fragmentation and fusion-evaporation reactions. Several new neutron-deficient nuclei can be produced in the <jats:sup>106</jats:sup>Cd + <jats:sup>112</jats:sup>Sn reaction. The corresponding production cross sections for the new neutron-deficient nuclei, <jats:sup>101, 112</jats:sup>Sb, <jats:sup>103</jats:sup>Te, and <jats:sup>106, 107</jats:sup>I, are 2.0 nb, 4.1 nb, 6.5 nb, 0.4 <jats:inline-formula> <jats:tex-math><?CDATA $ \mu $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064105_M17.jpg" xlink:type="simple" /> </jats:inline-formula>b and 1.0 <jats:inline-formula> <jats:tex-math><?CDATA $ \mu $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064105_M18.jpg" xlink:type="simple" /> </jats:inline-formula>b, respectively. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The newly observed isomer and ground-state band in the odd-<jats:italic>Z</jats:italic> neutron-rich rare-earth nucleus <jats:sup>163</jats:sup>Eu are investigated by using the cranked shell model (CSM), with pairing treated by the particle-number conserving (PNC) method. This is the first time detailed theoretical investigations are performed of the observed 964(1) keV isomer and ground-state rotational band in <jats:sup>163</jats:sup>Eu. The experimental data are reproduced very well by the theoretical results. The configuration of the 964(1) keV isomer is assigned as the three-particle state <jats:inline-formula> <jats:tex-math><?CDATA $\displaystyle\frac{13}{2}^{-}\left(\nu\displaystyle\frac{7}{2}^{+}[633]\otimes\nu\displaystyle\frac{1}{2}^{-}[521]\otimes\pi\displaystyle\frac{5}{2}^{+}[413]\right)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064106_M1.jpg" xlink:type="simple" /> </jats:inline-formula>. More low-lying multi-particle states are predicted in <jats:sup>163</jats:sup>Eu. Due to its significant effect on the nuclear mean field, the high-order <jats:inline-formula> <jats:tex-math><?CDATA $\varepsilon_{6}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064106_M2.jpg" xlink:type="simple" /> </jats:inline-formula> deformation plays an important role in the energy and configuration assignment of the multi-particle states. Compared to its neighboring even-even nuclei <jats:sup>162</jats:sup>Sm and <jats:sup>164</jats:sup>Gd, there is a 10%~15% increase of <jats:inline-formula> <jats:tex-math><?CDATA $J^{(1)}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064106_M3.jpg" xlink:type="simple" /> </jats:inline-formula> of the one-particle ground-state band in <jats:sup>163</jats:sup>Eu. This is explained by the pairing reduction due to the blocking of the nucleon on the proton <jats:inline-formula> <jats:tex-math><?CDATA $\pi\displaystyle\frac{5}{2}^{+}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064106_M4.jpg" xlink:type="simple" /> </jats:inline-formula>[413] orbital in <jats:sup>163</jats:sup>Eu. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this study, we investigate the ion-ball screening model (model (I)), focused on the screening electrostatic potential per electron under the Wigner-Seitz approximation and the <jats:italic>Q</jats:italic>-value correction. By considering the changes of the Coulomb free energy and the effects of strong electron screening (SES) on the <jats:italic>Q</jats:italic>-value and the Coulomb chemical potential, we discuss the linear-response screening model (model (II)). We also analyze the influence of the SES on the <jats:inline-formula> <jats:tex-math><?CDATA $ \beta^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064107_M2.jpg" xlink:type="simple" /> </jats:inline-formula> decay antineutrino energy loss rate by considering the corrections of the <jats:italic>Q</jats:italic>-value, the electron chemical potential, and electron energy, as well as the shell and pair effects. The antineutrino energy loss rate is found to increase by two orders of magnitude (e.g., the SES enhancement factor reaches 651.9 for model (II)) due to the SES effect. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Nuclear matrix elements (NME) and phase space factors (PSF) entering the half-life formulas of the double-beta decay (DBD) process are two key quantities whose accurate computation still represents a challenge. In this study, we propose a new approach of calculating these, namely the direct computation of their product as an unique formula. This procedure allows a more coherent treatment of the nuclear approximations and input parameters appearing in both quantities and avoids possible confusion in the interpretation of DBD data due to different individual expressions adopted for PSF and NME (and consequently their reporting in different units) by different authors. Our calculations are performed for both two neutrino ( <jats:inline-formula> <jats:tex-math><?CDATA $ 2\nu\beta\beta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064108_M1.jpg" xlink:type="simple" /> </jats:inline-formula>) and neutrinoless ( <jats:inline-formula> <jats:tex-math><?CDATA $ 0\nu\beta\beta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064108_M2.jpg" xlink:type="simple" /> </jats:inline-formula>) decay modes, for five nuclei of the most experimental interest. Further, using the most recent experimental limits for <jats:inline-formula> <jats:tex-math><?CDATA $ 0\nu\beta\beta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_6_064108_M3.jpg" xlink:type="simple" /> </jats:inline-formula> decay half-lives, we provide new constraints on the light mass neutrino parameter. Finally, by separating the factor representing the axial-vector constant to the forth power in the half-life formulas, we advance suggestions on how to reduce the errors introduced in the calculation by the uncertain value of this constant, exploiting the DBD data obtained from different isotopes and/or decay modes. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In our previous study, the deduced Langevin equation has been applied to investigate the isoscalar giant monopole resonance. In the current study, the framework is extended to study the isovector giant dipole resonance (IVGDR). The potential well in the IVGDR is calculated by separating the neutron and proton densities based on the Hartree-Fock ground state. Subsequently, the Langevin equation is solved self-consistently, resulting in the centroid energy of the IVGDR without width. The symmetry energy around the density of 0.02 fm<jats:sup>−3</jats:sup> contributes the most to the potential well in the IVGDR. By comparison with the updated experimental data of IVGDR energies in spherical nuclei, the calculations within 37 sets of Skyrme functionals suggest the symmetry energy to be in the range of 8.13-9.54 MeV at a density of 0.02 fm<jats:sup>−3</jats:sup>. </jats:p>