Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>The isoscaling parameters <jats:inline-formula> <jats:tex-math><?CDATA $\alpha_{\rm eval}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084101_M1.jpg" xlink:type="simple" /> </jats:inline-formula> in the fissioning systems, i.e., those extracted from the Evaluated Nuclear Data Library (ENDF/B-VIII.0) and the Joint Evaluated Fission and Fusion File (JEFF-3.3), show an obvious difference from simple statistic model prediction where only the symmetry energy plays the dominant role. To explain the <jats:inline-formula> <jats:tex-math><?CDATA $\alpha_{\rm eval}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084101_M2.jpg" xlink:type="simple" /> </jats:inline-formula> as a function of the charge number of the fission fragment, a statistic scission point model is adopted. Our analysis shows that the effects of the shell correction, nuclear shape deformation, and intrinsic temperature of fission fragments are indispensable as well as the symmetry energy. Furthermore, an alternative method for extracting the intrinsic temperatures of fission fragments is proposed based on the isoscaling relationship in fission fragments. The intrinsic temperatures of the light fragments are higher than those of the heavy fragments. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>A systematic analysis on experimental data of the half-lives of nuclear double- <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_45_8_084102_M1.jpg" xlink:type="simple" /> </jats:inline-formula> decays with two neutrinos ( <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_45_8_084102_M2.jpg" xlink:type="simple" /> </jats:inline-formula>) is performed based on the analytical formula proposed by Primakoff and Rosen. We improve the formula by considering the shell effects and refining the energy dependence of the phase-space factor. This improved formula can closely describe all available experimental half-lives of <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_45_8_084102_M3.jpg" xlink:type="simple" /> </jats:inline-formula> decays, both for ground-state transitions and transitions from ground states of parent nuclei to the first <jats:inline-formula> <jats:tex-math><?CDATA $ 0^{+} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084102_M4.jpg" xlink:type="simple" /> </jats:inline-formula> excited states of daughter nuclei. The calculated half-lives agree with the experimental data of ground-state transitions of all known eleven nuclei with an average factor of 2.3. Further predictions are provided for <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_45_8_084102_M5.jpg" xlink:type="simple" /> </jats:inline-formula>-decay candidates with decay energies above 0.5 MeV. We compare different theoretical predictions and emphasize the importance of experimental measurements on the half-lives of double- <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_45_8_084102_M6.jpg" xlink:type="simple" /> </jats:inline-formula> transitions between the ground state of <jats:inline-formula> <jats:tex-math><?CDATA $ ^{48} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084102_M7.jpg" xlink:type="simple" /> </jats:inline-formula>Ca, <jats:inline-formula> <jats:tex-math><?CDATA $ ^{76} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084102_M8.jpg" xlink:type="simple" /> </jats:inline-formula>Ge, and <jats:inline-formula> <jats:tex-math><?CDATA $ ^{136} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084102_M9.jpg" xlink:type="simple" /> </jats:inline-formula>Xe and the first <jats:inline-formula> <jats:tex-math><?CDATA $ 0^{+} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084102_M10.jpg" xlink:type="simple" /> </jats:inline-formula> excited states of their corresponding daughter nuclei, which will be very useful for understanding the underlying mechanisms of double- <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_45_8_084102_M11.jpg" xlink:type="simple" /> </jats:inline-formula> decays and for further studying the shell effects on nuclear transition matrix elements. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The isospin effects of projectile fragmentation at intermediate energies are investigated using an isospin-dependent Boltzmann-Langevin model. The collisions of mass-symmetric reactions including <jats:sup>58</jats:sup>Fe, <jats:sup>58</jats:sup>Ni + <jats:sup>58</jats:sup>Fe, and <jats:sup>58</jats:sup>Ni at intermediate energies, in the 30 to 100 MeV/A range, are studied for different symmetry energies. Yield ratios of the isotopic, isobaric, and isotonic pairs of fragments from the intermediate-mass region using three symmetry energies are extracted as functions of the <jats:italic>N/Z</jats:italic> ratio of the composite systems in the entrance channel and the incident energies. It is found that the yield ratios are sensitive to symmetry energies, especially for neutron-rich systems, and the calculations using soft symmetry energy are closer to the experimental data. The isospin effect is stronger for the soft symmetry energy, owing to the competition of the repulsive Coulomb force and the symmetry energy attractive force on the proton. For the first time, the splits are presented, revealing a transition from the isospin equilibrium at lower energies to translucency at intermediate energies. The results show a degree of transparency in that intermediate mass fragments undergo a transition from dependence on the composite systems in the entrance channel to reliance on the projectile and target nuclei. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>A rovibrational model, including anharmonic, centrifugal, and Coriolis corrections, is used to calculate π, <jats:italic>K</jats:italic>,<jats:italic>N</jats:italic>, and Ʃ orbital and radial resonances. The four orbital excitations of the π meson correspond to the <jats:italic>b</jats:italic>(1235), π<jats:sub>2</jats:sub>(1670), <jats:italic>b</jats:italic> <jats:sub>3</jats:sub>(2030), and π<jats:sub>4</jats:sub>(2250) resonances. Its first four radial excitations correspond to the π(1300), π(1800), π(2070), and π(2360) resonances. The orbital excitations of the <jats:italic>K</jats:italic> meson are interpreted as the <jats:italic>K</jats:italic> <jats:sub>1</jats:sub>(1270), <jats:italic>K</jats:italic> <jats:sub>2</jats:sub>(1770), <jats:italic>K</jats:italic> <jats:sub>3</jats:sub>(2320), and <jats:italic>K</jats:italic> <jats:sub>4</jats:sub>(2500) resonances; its radial excitations correspond to the <jats:italic>K</jats:italic>(1460) and <jats:italic>K</jats:italic>(1830) resonances. The <jats:italic>N</jats:italic> orbital excitations are identified with the <jats:italic>N</jats:italic>(1520), <jats:italic>N</jats:italic>(1680), <jats:italic>N</jats:italic>(2190), <jats:italic>N</jats:italic>(2220), and <jats:italic>N</jats:italic>(2600) resonances. The first four radial excitations of the <jats:italic>N</jats:italic> family correspond to the <jats:italic>N</jats:italic>(1440), <jats:italic>N</jats:italic>(1880), <jats:italic>N</jats:italic>(2100), and <jats:italic>N</jats:italic>(2300) resonances. The orbital excitations of the Ʃ baryon are associated with the Ʃ(1670), Ʃ(1915), Ʃ(2100), and Ʃ(2250) resonances, whereas its radial excitations are identified with the Ʃ(1660), Ʃ(1770), and Ʃ(1880) resonances. The proposed rovibrational model calculations show a good agreement with the corresponding experimental values and allow for the prediction of hadron resonances, thereby proving to be useful for the interpretation of excited hadron spectra. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a preliminary study of charge exchange heavy ion induced reactions based on the constrained molecular dynamics (CoMD) model. The purpose is to test the capability of the model in predicting the occurrence of single charge exchange (SCE) and double charge exchange (DCE) exit channels for three different entrance channels at the same laboratory incident energy. The nuclear reaction dynamics and nuclear interaction within the CoMD approach are the only ingredients that have given, at this stage, promising results for SCE and DCE cross section calculations. The obtained results suggest an upgrade and possible future employment of the model for studies relating to the production of exotic nuclei through charge exchange reactions or DCE reactions and their connection with neutrinoless double beta decay.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A scheme to solve the Hamiltonian in the interacting boson-fermion model in terms of the <jats:italic>SU</jats:italic>(3) coupling basis is introduced, through which the effects of an odd particle on shape phase transitions (SPTs) in odd-<jats:italic>A</jats:italic> nuclei are examined by comparing the critical behaviors of some selected quantities in odd-even and even-even systems. The results indicate that the spherical to prolate (<jats:italic>U</jats:italic>(5)-<jats:italic>SU</jats:italic>(3)) SPT and spherical to <jats:inline-formula> <jats:tex-math><?CDATA $ \gamma $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084106_M1.jpg" xlink:type="simple" /> </jats:inline-formula>-soft (<jats:italic>U</jats:italic>(5)-<jats:italic>O</jats:italic>(6)) SPT may clearly occur in the odd-even system with the SPT signatures revealed by various quantities including the excitation energies, energy ratio, <jats:inline-formula> <jats:tex-math><?CDATA $ B(E2) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084106_M2.jpg" xlink:type="simple" /> </jats:inline-formula> ratio, quadrupole moments, and one-particle-transfer spectroscopic intensities. In particular, the results indicate that the spherical to prolate SPT in the odd-even system can even be strengthened by the effects of the odd particle with the large fluctuations of the quadrupole deformations appearing near the critical point. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The dynamics of high-energy proton-induced spallation reactions on target nuclides of <jats:sup>56</jats:sup>Fe, <jats:sup>58</jats:sup>Ni, <jats:sup>107</jats:sup>Ag, <jats:sup>112</jats:sup>Cd, <jats:sup>184</jats:sup>W, <jats:sup>181</jats:sup>Ta, <jats:sup>197</jats:sup>Au, and <jats:sup>208</jats:sup>Pb are investigated with the quantum molecular dynamics transport model motivated by the China initiative Accelerator Driven System (CiADS) in Huizhou and the China Spallation Neutron Source (CSNS) in Dongguan. The production mechanism of light nuclides and fission fragments is thoroughly analyzed, and the results obtained thereby are compared with available experimental data. The statistical code GEMINI is employed in conjunction with a transport model for describing the decay of primary fragments. For the treatment of cluster emission during the preequilibrium stage, a surface coalescence model is implemented into the model. It is found that the available data in terms of total fragment yields are well reproduced in the combined approach for spallation reactions both on the heavy and light targets. The energetic light nuclides (deuteron, triton, helium isotopes etc) mainly created during the preequilibrium stage are treated within the framework of surface coalescence, whereas their evaporation is described in the conventional manner by the GEMINI code. With this combined approach, a good overall description of light clusters and neutron emission is obtained, and some discrepancies with the experimental data are discussed. Possible production of radioactive isotopes in the spallation reactions is also analyzed, i.e., the <jats:sup>6,8</jats:sup>He energy spectra. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Proton capture reactions on Mg isotopes are significant in the Mg-Al cycle in stellar <jats:italic>H</jats:italic>-burning. In particular, the resonance strengths and branching ratios of low-energy resonances in <jats:sup>25</jats:sup>Mg( <jats:inline-formula> <jats:tex-math><?CDATA $ p,\gamma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084108_M1.jpg" xlink:type="simple" /> </jats:inline-formula>)<jats:sup>26</jats:sup>Al reactions determine the production of <jats:sup>26</jats:sup>Al, which is one of the most important long-lived radioactive nuclei in nuclear astrophysics. In this article, we report our first experiment using the intense proton beam of approximately 2 mA provided by the JUNA accelerator ground laboratory and a new technique that can minimize the composition change of targets under intense beam irradiation. The resonance strengths and branching ratios of <jats:italic>E</jats:italic> = 214, 304, and 326 keV resonances in the reactions of <jats:sup>24</jats:sup>Mg( <jats:inline-formula> <jats:tex-math><?CDATA $ p,\gamma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084108_M2.jpg" xlink:type="simple" /> </jats:inline-formula>)<jats:sup>25</jats:sup>Al, <jats:sup>25</jats:sup>Mg( <jats:inline-formula> <jats:tex-math><?CDATA $ p,\gamma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084108_M3.jpg" xlink:type="simple" /> </jats:inline-formula>)<jats:sup>26</jats:sup>Al, and <jats:sup>26</jats:sup>Mg( <jats:inline-formula> <jats:tex-math><?CDATA $ p,\gamma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084108_M4.jpg" xlink:type="simple" /> </jats:inline-formula>)<jats:sup>27</jats:sup>Al, respectively, were measured with high accuracy. The success of this experiment provides a good calibration for the nuclear astrophysical experiment at the Jinping underground laboratory. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In our previous studies [Phys. Rev. C 97, 044619 (2018); Phys. Rev. C 103, 044610 (2021)], a universal odd-even staggering (OES) has been observed in extensive cross sections of isotopes not far from stability, measured for different fragmentation and spallation reactions. Four OES relations have been proposed on the basis of this OES universality. However, it is still unclear whether this OES universality and OES relations are applicable to many isotopes near the drip-lines. Here, the OES in recent experimental cross sections of very neutron-rich nuclei approaching the drip-line (from <jats:inline-formula> <jats:tex-math><?CDATA $^{76}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084109_M1.jpg" xlink:type="simple" /> </jats:inline-formula>Ge, <jats:inline-formula> <jats:tex-math><?CDATA $^{82}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084109_M2.jpg" xlink:type="simple" /> </jats:inline-formula>Se+ <jats:inline-formula> <jats:tex-math><?CDATA $^{9}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084109_M3.jpg" xlink:type="simple" /> </jats:inline-formula>Be) is quantitatively investigated, to further validate the OES universality and OES relations. The OES magnitudes in these experimental data approaching the neutron drip-line generally agree with those evaluated previously, mainly from experimental data near stability. New OES evaluations derived from these experimental data are also recommended for more exotic nuclei near the neutron drip-line, which extends the conclusions of our previous OES studies. In addition, the OES relation calculations are consistent with these experimental data of very neutron-rich nuclides according to their comparisons in this work. Finally, comparisons with additional experimental data (from <jats:inline-formula> <jats:tex-math><?CDATA $^{238}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084109_M4.jpg" xlink:type="simple" /> </jats:inline-formula>U+ <jats:inline-formula> <jats:tex-math><?CDATA $^{9}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084109_M5.jpg" xlink:type="simple" /> </jats:inline-formula>Be) also support that new OES evaluations and OES relation calculations can be applied for exotic nuclei near the neutron drip-line. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The chiral phase transition and equation of state are studied within a novel self-consistent mean-field approximation of the two-flavor Nambu-Jona-Lasinio model. In this newly developed model, modifications to the chemical <jats:italic>μ</jats:italic> and chiral chemical <jats:inline-formula> <jats:tex-math><?CDATA $\mu_5$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084110_M1.jpg" xlink:type="simple" /> </jats:inline-formula> potentials are naturally included by introducing vector and axial-vector channels from Fierz-transformed Lagrangian to the standard Lagrangian. In the proper-time scheme, the chiral phase transition is a crossover in the <jats:inline-formula> <jats:tex-math><?CDATA $T-\mu$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084110_M2.jpg" xlink:type="simple" /> </jats:inline-formula> plane. However, when <jats:inline-formula> <jats:tex-math><?CDATA $\mu_5$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084110_M3.jpg" xlink:type="simple" /> </jats:inline-formula> is incorporated, our study demonstrates that a first order phase transition may emerge. Furthermore, the chiral imbalance will soften the equation of state of quark matter. The mass-radius relationship and tidal deformability of quark stars are calculated. The maximum mass and radius decrease as <jats:inline-formula> <jats:tex-math><?CDATA $\mu_5$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_8_084110_M4.jpg" xlink:type="simple" /> </jats:inline-formula> increases. Our study also indicates that the vector and axial-vector channels exhibit an opposite influence on the equation of state. </jats:p>