Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>In this exploratory study, near-threshold scattering of <jats:italic>D</jats:italic> and <jats:inline-formula> <jats:tex-math><?CDATA $\bar{D}^*$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103103_M1.jpg" xlink:type="simple" /> </jats:inline-formula> meson is investigated using lattice QCD with <jats:inline-formula> <jats:tex-math><?CDATA $N_f=2+1+1$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103103_M2.jpg" xlink:type="simple" /> </jats:inline-formula> twisted mass fermion configurations. The calculation is performed in the coupled-channel Lüscher finite-size formalism. The study focuses on the channel with <jats:inline-formula> <jats:tex-math><?CDATA $I^G(J^{PC})=1^+(1^{+-})$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103103_M3.jpg" xlink:type="simple" /> </jats:inline-formula> where the resonance-like structure <jats:inline-formula> <jats:tex-math><?CDATA $Z_c(3900)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103103_M4.jpg" xlink:type="simple" /> </jats:inline-formula> was discovered. We first identify the two most relevant channels and the lattice study is performed in the two-channel scattering model. Combined with the two-channel Ross-Shaw theory, scattering parameters are extracted from the energy levels by solving the generalized eigenvalue problem. Our results for the scattering length parameters suggest that for the particular lattice parameters that we studied, the best fit parameters do not correspond to the peak in the elastic scattering cross-section near the threshold. Furthermore, in the zero-range Ross-Shaw theory, the scenario of a narrow resonance close to the threshold is disfavored beyond the 3 <jats:inline-formula> <jats:tex-math><?CDATA $\sigma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103103_M5.jpg" xlink:type="simple" /> </jats:inline-formula> level. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Motivated by the rapid development of heavy flavor physics experiments, we study the tree-dominated nonleptonic <jats:inline-formula> <jats:tex-math><?CDATA $ \bar{B}_{u,d,s}^* \to D_{u,d,s}^*V $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103104_M2.jpg" xlink:type="simple" /> </jats:inline-formula> ( <jats:inline-formula> <jats:tex-math><?CDATA $ V = D^{*-},D_s^{*-},K^{*-},{\rho}^- $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103104_M3.jpg" xlink:type="simple" /> </jats:inline-formula>) decays within the factorization approach. The relevant transition form factors are calculated by employing the covariant light-front quark model. Helicity amplitudes are calculated and analyzed in detail, and a very clear hierarchical structure <jats:inline-formula> <jats:tex-math><?CDATA $ |H_{-0}| \approx 2|H_{00}| \gt |H_{0-}|\approx|H_{&#x2013;}| \gt |H_{0+}|\approx|H_{++}| $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103104_M4.jpg" xlink:type="simple" /> </jats:inline-formula> is presented. The branching fractions are computed and discussed. Numerically, the CKM-favored <jats:inline-formula> <jats:tex-math><?CDATA $ \bar{B}^*_q\to D^*_q \rho^{-} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103104_M5.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ D^*_q D_s^{*-} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103104_M6.jpg" xlink:type="simple" /> </jats:inline-formula> decays have relatively large branching fractions, <jats:inline-formula> <jats:tex-math><?CDATA $ \gtrsim {\cal O}(10^{-8}) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103104_M7.jpg" xlink:type="simple" /> </jats:inline-formula>, and could be observed by LHC and Belle-II experiments in the future. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We consider chiral perturbation theory with an explicit broad <jats:italic>σ</jats:italic>-meson and study its contribution to the scalar form factors of the pion and the nucleon. Our goal is to learn more about resonance saturation in the scalar sector. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>There are different constructions of the flux of triad in loop quantum gravity, namely the fundamental and alternative flux operators. In parallel to the consistency check on the two versions of operator by the algebraic calculus in the literature, we check their consistency by the graphical calculus. Our calculation based on the original Brink graphical method is obviously simpler than the algebraic calculation. It turns out that our consistency check fixes the regulating factor <jats:inline-formula> <jats:tex-math><?CDATA $ \kappa_{\rm reg}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103106_M1.jpg" xlink:type="simple" /> </jats:inline-formula> of the Ashtekar-Lewandowski volume operator as <jats:inline-formula> <jats:tex-math><?CDATA $ \displaystyle\frac{1}{2}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_103106_M2.jpg" xlink:type="simple" /> </jats:inline-formula>, which corrects its previous value in the literature. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The spallation cross-section data for the long-lived fission products (LLFPs) are scarce but required for the design of accelerator driven systems. In this paper, the isospin dependent quantum molecular dynamics model and the statistical code GEMINI are applied to simulate deuteron-induced spallation in the energy region of GeV/nucleon. By comparing the calculations with the experimental data, the applicability of the model is verified. The model is then applied to simulate the spallation of <jats:sup>90</jats:sup>Sr, <jats:sup>93</jats:sup>Zr, <jats:sup>107</jats:sup>Pd, and <jats:sup>137</jats:sup>Cs induced by deuterons at 200, 500 and 1000 MeV/nucleon. The cross-sections of isotopes, the cross-sections of long-lived nuclei, and the reaction energy are presented. Using the above observables, the feasibility of LLFP transmutation by spallation is discussed. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Excited states of odd-odd nucleus <jats:sup>92</jats:sup>Nb and odd-A nucleus <jats:sup>93</jats:sup>Nb were populated in the <jats:sup>6</jats:sup>Li+ <jats:sup>89</jats:sup>Y reaction with an incident energy of 34 MeV. The processes that produce <jats:sup>92,93</jats:sup>Nb and can be measured by a combination of light charged particle and gamma ray measurements are discussed. Twenty new transitions are observed and eight new levels are constructed in <jats:sup>92</jats:sup>Nb, and in addition two new transitions are added to the level scheme of <jats:sup>93</jats:sup>Nb. Using shell model calculations, the low-lying structure of <jats:sup>92</jats:sup>Nb is investigated and compared with the experimental results. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>This study investigates the structural properties of super-heavy nuclei with <jats:italic>Z</jats:italic> = 130 by adopting the relativistic mean-field (RMF) theory within an axially deformed oscillator basis with the NL3 force parameter set. We study the binding energies, quadrupole deformation, nuclear radii, neutron separation energies, and other bulk properties. Moreover, we analyze the favorable decay modes for clear cognitive content of nuclei, such as alpha decay, using different formulae including the Viola-Seaberg, analytical formula of Royer, universal curve formula, and universal decay law. We compare these with the corresponding fission process. The spontaneous fission of super-heavy nuclei is studied with <jats:inline-formula> <jats:tex-math><?CDATA $ Z = 130 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_104103_M2.jpg" xlink:type="simple" /> </jats:inline-formula> within the mass region <jats:inline-formula> <jats:tex-math><?CDATA $ 310 \leqslant A\leqslant 340 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_104103_M3.jpg" xlink:type="simple" /> </jats:inline-formula>. The results exhibit good agreement with finite range droplet model (FRDM) data. This formalism presents a significant step forward in the study of the structure and decay modes of the isotopes of <jats:italic>Z</jats:italic> = 130. With this appraisal, we investigate the possible shell/sub-shell closure for super-heavy nuclei adjacent by decay chains of alpha and other radioactive decay particles. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>It is widely believed that the screening mechanism is an essential feature for the modified gravity theory. Although this mechanism has been examined thoroughly in the past decade, their analyses are based on a conventional fluid prescription for the matter-sector configuration. In this paper, we demonstrate a new formulation of the chameleon mechanism in <jats:italic>F</jats:italic>(<jats:italic>R</jats:italic>) gravity theory, to shed light on quantum-field theoretical effects on the chameleon mechanism as well as the related scalaron physics, induced by the matter sector. We show a possibility that the chameleon mechanism is absent in the early Universe based on a scale-invariant-extended scenario beyond the standard model of particle physics, in which a realistic electroweak phase transition, yielding the right amount of baryon asymmetry of Universe today, simultaneously breaks the scale invariance in the early Universe. We also briefly discuss the oscillation of the scalaron field and indirect generation of non-tensorial gravitational waves induced by the electroweak phase transition. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Neutrinos produced from <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_43_10_105102_M34-5.jpg" xlink:type="simple" /> </jats:inline-formula>-ray bursts (GRBs) carry significant physical information. The electron density in the GRBs outflow is very large. In this study, we calculate the matter effect on neutrinos when they propagate through such a dense region. The average survival probability and the flavor ratio of neutrinos are determined. The ratio of resonant neutrino energy from different spherical shells provides the information of power index <jats:italic>N</jats:italic> for the power-law distribution of electrons in the hot fireball model. Electron density in the magnetic jet model is sufficiently lower than in the hot fireball model. The matter effect on neutrinos can be used to distinguish these two models. The coherent effect of strongly lensed PeV neutrinos is also discussed. The average survival probability of strongly-lensed electron neutrinos in the normal and inverted hierarchical cases are presented. The results show that this coherent effect can be used to determine the hierarchical mass of neutrinos. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Based on the cosmological principle and quantum Yang-Mills gravity in the super-macroscopic limit, we obtain an exact recession velocity and cosmic redshift z, as measured in an inertial frame <jats:inline-formula> <jats:tex-math><?CDATA $ F\equiv F(t,x,y,z). $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M1.jpg" xlink:type="simple" /> </jats:inline-formula> For a matter-dominated universe, we have the effective cosmic metric tensor <jats:inline-formula> <jats:tex-math><?CDATA $ G_{\mu\nu}(t) = (B^2(t),-A^2(t), -A^2(t),-A^2(t)),$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M2-1.jpg" xlink:type="simple" /> </jats:inline-formula> <jats:inline-formula> <jats:tex-math><?CDATA $ \ A\propto B\propto t^{1/2} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M2.jpg" xlink:type="simple" /> </jats:inline-formula>, where <jats:inline-formula> <jats:tex-math><?CDATA $ t $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M3.jpg" xlink:type="simple" /> </jats:inline-formula> has the operational meaning of time in <jats:inline-formula> <jats:tex-math><?CDATA $ F $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M4.jpg" xlink:type="simple" /> </jats:inline-formula> frame. We assume a cosmic action <jats:inline-formula> <jats:tex-math><?CDATA $ S\equiv S_{\rm cos} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M5.jpg" xlink:type="simple" /> </jats:inline-formula> involving <jats:inline-formula> <jats:tex-math><?CDATA $ G_{\mu\nu}(t) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M6.jpg" xlink:type="simple" /> </jats:inline-formula> and derive the ‘Okubo equation’ of motion, <jats:inline-formula> <jats:tex-math><?CDATA $ G^{\mu\nu}(t)\partial_\mu S \partial_\nu S - m^2 = 0 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M7.jpg" xlink:type="simple" /> </jats:inline-formula>, for a distant galaxy with mass <jats:inline-formula> <jats:tex-math><?CDATA $ m $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M8.jpg" xlink:type="simple" /> </jats:inline-formula>. This cosmic equation predicts an exact recession velocity, <jats:inline-formula> <jats:tex-math><?CDATA $ \dot{r} = rH/[1/2 +\sqrt{1/4+r^2H^2/C_o^2} ] \lt C_o $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M9.jpg" xlink:type="simple" /> </jats:inline-formula>, where <jats:inline-formula> <jats:tex-math><?CDATA $ H = \dot{A}(t)/A(t) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M10.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ C_o = B/A $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M11.jpg" xlink:type="simple" /> </jats:inline-formula>, as observed in the inertial frame <jats:inline-formula> <jats:tex-math><?CDATA $ F $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M12.jpg" xlink:type="simple" /> </jats:inline-formula>. For small velocities, we have the usual Hubble's law <jats:inline-formula> <jats:tex-math><?CDATA $ \dot{r} \approx rH $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M13.jpg" xlink:type="simple" /> </jats:inline-formula> for recession velocities. Following the formulation of the accelerated Wu-Doppler effect, we investigate cosmic redshifts z as measured in <jats:inline-formula> <jats:tex-math><?CDATA $ F $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M14.jpg" xlink:type="simple" /> </jats:inline-formula>. It is natural to assume the massless Okubo equation, <jats:inline-formula> <jats:tex-math><?CDATA $ G^{\mu\nu}(t)\partial_\mu \psi_e \partial_\nu \psi_e = 0 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M15.jpg" xlink:type="simple" /> </jats:inline-formula>, for light emitted from accelerated distant galaxies. Based on the principle of limiting continuation of physical laws, we obtain a transformation for covariant wave 4-vectors between and inertial and an accelerated frame, and predict a relationship for the exact recession velocity and cosmic redshift, <jats:inline-formula> <jats:tex-math><?CDATA $ z = [(1+V_r)/(1-V_r^2)^{1/2}] - 1 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M16.jpg" xlink:type="simple" /> </jats:inline-formula>, where <jats:inline-formula> <jats:tex-math><?CDATA $ V_r = \dot{r}/C_o \lt 1 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M17.jpg" xlink:type="simple" /> </jats:inline-formula>, as observed in the inertial frame <jats:inline-formula> <jats:tex-math><?CDATA $ F $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_10_105103_M18.jpg" xlink:type="simple" /> </jats:inline-formula>. These predictions of the cosmic model are consistent with experiments for small velocities and should be further tested. </jats:p>