Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>As a charged fermion drops into a BTZ black hole, the laws of thermodynamics and the weak cosmic censorship conjecture are investigated in both the normal and extended phase space, where the cosmological parameter and renormalization length are regarded as extensive quantities. In the normal phase space, the first and second law of thermodynamics, and the weak cosmic censorship are found to be valid. In the extended phase space, although the first law and weak cosmic censorship conjecture remain valid, the second law is dependent on the variation of the renormalization energy d<jats:italic>K</jats:italic>. Moreover, in the extended phase space, the configurations of extremal and near-extremal black holes are not changed, as they are stable, while in the normal phase space, the extremal and near-extremal black holes evolve into non-extremal black holes. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We report the Neutrino-less Double Beta Decay (NLDBD) search results from PandaX-II dual-phase liquid xenon time projection chamber. The total live time used in this analysis is 403.1 days from June 2016 to August 2018. With NLDBD-optimized event selection criteria, we obtain a fiducial mass of 219 kg of natural xenon. The accumulated xenon exposure is 242 kg·yr, or equivalently 22.2 kg·yr of <jats:sup>136</jats:sup>Xe exposure. At the region around <jats:sup>136</jats:sup>Xe decay <jats:italic>Q</jats:italic>-value of 2458 keV, the energy resolution of PandaX-II is 4.2%. We find no evidence of NLDBD in PandaX-II and establish a lower limit for decay half-life of 2.1 <jats:inline-formula> <jats:tex-math><?CDATA $ \times 10^{23} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113001_M3.jpg" xlink:type="simple" /> </jats:inline-formula> yr at the 90% confidence level, which corresponds to an effective Majorana neutrino mass <jats:inline-formula> <jats:tex-math><?CDATA $m_{\beta \beta} \lt (1.4 - 3.7)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113001_M4.jpg" xlink:type="simple" /> </jats:inline-formula> eV. This is the first NLDBD result reported from a dual-phase xenon experiment. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We investigate the <jats:inline-formula> <jats:tex-math><?CDATA $ J/\psi \phi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M2.jpg" xlink:type="simple" /> </jats:inline-formula> invariant mass distribution in the <jats:inline-formula> <jats:tex-math><?CDATA $ e^+e^-\to \gamma J/\psi\phi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M3.jpg" xlink:type="simple" /> </jats:inline-formula> reaction at a center-of-mass energy of <jats:inline-formula> <jats:tex-math><?CDATA $ \sqrt{s} = 4.6 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M4.jpg" xlink:type="simple" /> </jats:inline-formula> GeV measured by the BESIII collaboration, which concluded that no significant signals were observed for <jats:inline-formula> <jats:tex-math><?CDATA $ e^+e^- \to \gamma X(4140) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M5.jpg" xlink:type="simple" /> </jats:inline-formula> because of the low statistics. We show, however, that the <jats:inline-formula> <jats:tex-math><?CDATA $ J/\psi \phi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M6.jpg" xlink:type="simple" /> </jats:inline-formula> invariant mass distribution is compatible with the existence of the <jats:inline-formula> <jats:tex-math><?CDATA $ X(4140) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M7.jpg" xlink:type="simple" /> </jats:inline-formula> state, appearing as a peak, and a strong cusp structure at the <jats:inline-formula> <jats:tex-math><?CDATA $ D^*_s\bar{D}^*_s $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M8.jpg" xlink:type="simple" /> </jats:inline-formula> threshold, resulting from the molecular nature of the <jats:inline-formula> <jats:tex-math><?CDATA $ X(4160) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M9.jpg" xlink:type="simple" /> </jats:inline-formula> state, which provides a substantial contribution to the reaction. This is consistent with our previous analysis of the <jats:inline-formula> <jats:tex-math><?CDATA $ B^+\to J/\psi\phi K^+ $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M10.jpg" xlink:type="simple" /> </jats:inline-formula> decay measured by the LHCb collaboration. We strongly suggest further measurements of this process with more statistics to clarify the nature of the <jats:inline-formula> <jats:tex-math><?CDATA $ X(4140) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M11.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ X(4160) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113101_M12.jpg" xlink:type="simple" /> </jats:inline-formula> resonances. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We reexamine the simplified dark matter (DM) models with fermionic DM particle and spin-0 mediator. The DM-nucleon scattering cross sections in these models are low-momentum suppressed at tree-level, but receive sizable loop-induced spin-independent contribution. We perform one-loop calculations for scalar-type and twist-2 DM-quark operators, and complete two-loop calculations for scalar-type DM-gluon operator. Analyzing the loop-level contribution from new operators, we find that future direct detection experiments could be sensitive to a fraction of the parameter space. The indirect detection and collider search also provide complementary constraints on these models.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study the drag force of a relativistic heavy quark using a holographic QCD model with conformal invariance broken by a background dilaton. The effects of the chemical potential and the confining scale on this quantity are analyzed. The drag force in this model is shown to be larger than that of <jats:inline-formula> <jats:tex-math><?CDATA ${\cal N}=4$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113103_M1.jpg" xlink:type="simple" /> </jats:inline-formula> supersymmetric Yang-Mills (SYM) plasma. In particular, the inclusion of the chemical potential and confining scale both enhance the drag force, in agreement with earlier findings. Moreover, we discuss how the chemical potential and confining scale influence the diffusion coefficient. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We propose to study the flavor properties of the top quark at the future Circular Electron Positron Collider (CEPC) in China. We systematically consider the full set of 56 real parameters that characterize the flavor-changing neutral interactions of the top quark, which can be tested at CEPC in the single top production channel. Compared with the current bounds from the LEP2 data and the projected limits at the high-luminosity LHC, we find that CEPC could improve the limits of the four-fermion flavor-changing coefficients by one to two orders of magnitude, and would also provide similar sensitivity for the two-fermion flavor-changing coefficients. Overall, CEPC could explore a large fraction of currently allowed parameter space that will not be covered by the LHC upgrade. We show that the <jats:italic>c</jats:italic>-jet tagging capacity at CEPC could further improve its sensitivity to top-charm flavor-changing couplings. If a signal is observed, the kinematic distribution as well as the <jats:italic>c</jats:italic>-jet tagging could be exploited to pinpoint the various flavor-changing couplings, providing valuable information about the flavor properties of the top quark. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>Inspired by the recent measurement of the process <jats:inline-formula> <jats:tex-math><?CDATA $ e^+e^-\rightarrow \Lambda\bar{\Lambda} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M2.jpg" xlink:type="simple" /> </jats:inline-formula>, we calculate the mass spectrum of the <jats:inline-formula> <jats:tex-math><?CDATA $ \phi $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M3.jpg" xlink:type="simple" /> </jats:inline-formula> meson with the GI model. For the excited vector strangeonium states <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(3S,\; 4S,\; 5S,\; 6S) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M4.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(2D,\; 3D,\; 4D,\; 5D) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M5.jpg" xlink:type="simple" /> </jats:inline-formula>, we investigate the electronic decay width with the Van Royen-Weisskopf formula, and the partial widths of the <jats:inline-formula> <jats:tex-math><?CDATA $ \Lambda\bar{\Lambda} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M6.jpg" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math><?CDATA $ \Xi^{-(*)}\bar{\Xi}^+ $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M7.jpg" xlink:type="simple" /> </jats:inline-formula>, and <jats:inline-formula> <jats:tex-math><?CDATA $ \Sigma^{+(*)}\bar{\Sigma}^{-(*)} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M8.jpg" xlink:type="simple" /> </jats:inline-formula> decay modes with the extended quark-pair creation model. We find that the electronic decay width of the <jats:inline-formula> <jats:tex-math><?CDATA $ D $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M9.jpg" xlink:type="simple" /> </jats:inline-formula>-wave vector strangeonium is about <jats:inline-formula> <jats:tex-math><?CDATA $ 3\sim8 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M10.jpg" xlink:type="simple" /> </jats:inline-formula> times larger than of the <jats:inline-formula> <jats:tex-math><?CDATA $ S $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M11.jpg" xlink:type="simple" /> </jats:inline-formula>-wave vector strangeonium. Around 2232 MeV, the partial decay width of the <jats:inline-formula> <jats:tex-math><?CDATA $ \Lambda\bar{\Lambda} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M12.jpg" xlink:type="simple" /> </jats:inline-formula> mode can be up to several MeV for <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(3^3S_1) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M13.jpg" xlink:type="simple" /> </jats:inline-formula>, while the partial <jats:inline-formula> <jats:tex-math><?CDATA $ \Lambda\bar{\Lambda} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M14.jpg" xlink:type="simple" /> </jats:inline-formula> decay width of <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(2^3D_1) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M15.jpg" xlink:type="simple" /> </jats:inline-formula> is <jats:inline-formula> <jats:tex-math><?CDATA $ {\cal{O}}(10^{-3}) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M16.jpg" xlink:type="simple" /> </jats:inline-formula> keV. If the threshold enhancement reported by the BESIII collaboration arises from the strangeonium meson, this state is very likely the <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(3^3S_1) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M17.jpg" xlink:type="simple" /> </jats:inline-formula> state. We also note that the <jats:inline-formula> <jats:tex-math><?CDATA $ \Lambda\bar{\Lambda} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M18.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ \Sigma^{+}\bar{\Sigma}^{-} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M19.jpg" xlink:type="simple" /> </jats:inline-formula> partial decay widths of the states <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(3^3D_1) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M20.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $ \phi(4^3S_1) $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_113105_M21.jpg" xlink:type="simple" /> </jats:inline-formula> are several MeV, which is sufficient to be observed in future experiments. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>One of the major open problems in theoretical physics is the lack of a consistent quantum gravity theory. Recent developments in our knowledge on thermodynamic phase transitions of black holes and their van der Waals-like behavior may provide an interesting quantum interpretation of classical gravity. Studying different methods of investigating phase transitions can extend our understanding of the nature of quantum gravity. In this paper, we present an alternative theoretical approach for finding thermodynamic phase transitions in the extended phase space. Unlike the standard methods based on the usual equation of state involving temperature, our approach uses a new quasi-equation constructed from the slope of temperature versus entropy. This approach addresses some of the shortcomings of the other methods and provides a simple and powerful way of studying the critical behavior of a thermodynamical system. Among the applications of this approach, we emphasize the analytical demonstration of possible phase transition points and the identification of the non-physical range of horizon radii for black holes.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The structure of neutron-rich Ca isotopes is studied in the spherical Skyrme-Hartree-Fock-Bogoliubov (SHFB) approach with SLy5, SLy5+T, and 36 sets of T<jats:italic>IJ</jats:italic> parametrizations. The calculated results are compared with the available experimental data for the average binding energies, two-neutron separation energies and charge radii. It is found that the SLy5+T, T31, and T32 parametrizations reproduce best the experimental properties, especially the neutron shell effects at <jats:italic>N</jats:italic> = 20, 28 and 32, and the recently measured two-neutron separation energy of <jats:sup>56</jats:sup>Ca. The calculations with the SLy5+T and T31 parametrizations are extended to isotopes near the neutron drip line. The neutron giant halo structure in the very neutron-rich Ca isotopes is not seen with these two interactions. However, depleted neutron central densities are found in these nuclei. By analyzing the neutron mean-potential, the reason for the bubble-like structure formation is given. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>The structural effect is believed to have no influence on the decay properties of medium and heavy-mass nuclei at excitation energies above the pairing gap. These properties can be described by statistical properties using so-called photon strength functions for different multipolarities, and directly related to the photoabsorption cross-section ( <jats:inline-formula> <jats:tex-math><?CDATA $\sigma_{\rm abs}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_114102_M1.jpg" xlink:type="simple" /> </jats:inline-formula>). <jats:inline-formula> <jats:tex-math><?CDATA $\sigma_{\rm abs}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_114102_M2.jpg" xlink:type="simple" /> </jats:inline-formula> is dominated by the electric giant dipole resonance at <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_11_114102_M3.jpg" xlink:type="simple" /> </jats:inline-formula> energy <jats:inline-formula> <jats:tex-math><?CDATA $\epsilon_\gamma \leqslant 40$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_43_11_114102_M4.jpg" xlink:type="simple" /> </jats:inline-formula> MeV. In this study, we construct two kinds of systematic giant dipole resonance parameters by fitting the experimental photoabsorption cross-sections. One is based on the microscopic relativistic quasiparticle random phase approximation approach, whereas the other is estimated by the phenomenological models within the Lorentzian representation. Both of them are demonstrated ot efficiently describe the experimental photoabsorption cross-sections available for medium to heavy-mass nuclei, and they can obtain more reliable predictions for the unknown nuclear system. </jats:p>