Relativistic symmetry breaking in light kaonic nuclei

As the experimental data from kaonic atoms and $K^{-}N$ scatterings imply that the $K^{-}$-nucleon interaction is strongly attractive at saturation density, there is a possibility to form $K^{-}$-nuclear bound states or kaonic nuclei. In this work, we investigate the ground-state properties of the light kaonic nuclei with the relativistic mean field theory. It is found that the strong attraction between $K^{-}$ and nucleons reshapes the scalar and vector meson fields, leading to the remarkable enhancement of the nuclear density in the interior of light kaonic nuclei and the manifest shift of the single-nucleon energy spectra and magic numbers therein. As a consequence, the pseudospin symmetry is shown to be violated together with enlarged spin-orbit splittings in these kaonic nuclei.Comment: 15 pages, 7 figure

4-(4-Chloro­phen­yl)-3-cyano-7-(4-meth­oxy­phen­yl)-5-oxo-5,6,7,8-tetra­hydro-4H-chromen-2-aminium methano­late

In the cation of the title organic ion pair compound, C23H20ClN2O3 +·CH3O−, the cyclo­hexyl ring shows a half-boat conformation and the dihedral angles between two benzene rings and the pyran ring are 83.14 (7) and 73.18 (9)°. In the crystal, centrosymmetrically related cations are linked into a dimer by pairs of N—H⋯N hydrogen bonds, generating an R 2 2(12) ring motif. The anion inter­acts with the dimer through an N—H⋯O hydrogen bond. π–π inter­actions between pyran rings of adjacent dimers, with a centroid–centroid distance of 3.861 (2) Å, are also observed

Coupled effects of local movement and global interaction on contagion

By incorporating segregated spatial domain and individual-based linkage into the SIS (susceptible-infected-susceptible) model, we investigate the coupled effects of random walk and intragroup interaction on contagion. Compared with the situation where only local movement or individual-based linkage exists, the coexistence of them leads to a wider spread of infectious disease. The roles of narrowing segregated spatial domain and reducing mobility in epidemic control are checked, these two measures are found to be conducive to curbing the spread of infectious disease. Considering heterogeneous time scales between local movement and global interaction, a log-log relation between the change in the number of infected individuals and the timescale $\tau$ is found. A theoretical analysis indicates that the evolutionary dynamics in the present model is related to the encounter probability and the encounter time. A functional relation between the epidemic threshold and the ratio of shortcuts, and a functional relation between the encounter time and the timescale $\tau$ are found