Further understanding the nature of Ω(2012)\Omega(2012) within a chiral quark model

In our previous works, we have analyzed the two-body strong decays of the low-lying $\Omega$ baryon states within a chiral quark model. The results show that the $\Omega(2012)$ resonance favors the three-quark state with $J^P=3/2^-$ classified in the quark model. With this assignment, in the present work we further study the three-body strong decay $\Omega(2012)\to \Xi^*(1530)\bar{K} \to \Xi\pi\bar{K}$ and coupled-channel effects on $\Omega(2012)$ from nearby channels $\Xi \bar{K}$, $\Omega\eta$ and $\Xi^*(1530)\bar{K}$ within the chiral quark model as well. It is found that the $\Omega(2012)$ resonance has a sizeable decay rate into the three-body final state $\Xi\pi\bar{K}$. The predicted ratio $R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}=\mathcal{B}[\Omega(2012)\to \Xi^*(1530)\bar{K}\to \Xi\pi\bar{K}]/\mathcal{B}[\Omega(2012)\to \Xi\bar{K}]\simeq 12\%$ is close to the up limit $11\%$ measured by the Belle Collaboration in 2019, however, our predicted ratio is too small to be comparable with the recent data $0.97\pm 0.31$. Furthermore, our results show that the coupled-channel effects on the $\Omega(2012)$ is not large, its components should be dominated by the bare three-quark state, while the proportion of the molecular components is only $\sim 16\%$. To clarify the nature of $\Omega(2012)$, the ratio $R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}$ is expected to be tested by other experiments.Comment: 7 pages, 3 figure

A reversible and visible colorimetric/fluorescent chemosensor for Al³⁺+ and F⁻ ions with a Large Stoke's shift

A quinoline-vinyl-dihydroxylphenyl linkage comprising a donor-π-bridge-acceptor structural motif, in which the quinoline serves as an electron-withdrawing core, has been synthesized and used as a fluorescent sensor (2) for the recognition of Al³⁺+ and F⁻ by colorimetry/fluorescence. The sensor 2 exhibited little fluorescence due to excited-state intramolecular proton transfer from the hydroxyl oxygens to the nitrogen of the quinoline moiety. By contrast, on coordination of Al³⁺+ or F⁻, sensor 2 afforded strong fluorescence. A reversible “off–on” optical switching mode has been constructed by sequential inputs from Al³⁺+ and F⁻ ions to the sensor 2 via different excitation and emission wavelengths. ¹H NMR and IR spectroscopic analysis revealed that the Al³⁺+ is coordinated to the quinoline nitrogen and phenolic oxygen atoms, whereas the F⁻ center is only coordinated by two phenolic oxygen atoms

Biphenyl-3,3′-dicarb­oxy­lic acid

The asymmetric unit of the title compound, C14H10O4, contains one half mol­ecule, the complete mol­ecule being generated by a twofold axis. The two benzene rings form a dihedral angle of 43.11 (5)°. Inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into one-dimensional zigzag chains. These chains are further connected into two-dimensional supra­molecular layers by weak π–π stacking inter­actions between neighbouring benzene rings, with centroid–centroid distances of 3.7648 (8) Å

Nanoscale anisotropic plastic deformation in single crystal GaN

Elasto-plastic mechanical deformation behaviors of c-plane (0001) and nonpolar GaN single crystals are studied using nanoindentation, cathodoluminescence, and transmission electron microscopy. Nanoindentation tests show that c-plane GaN is less susceptible to plastic deformation and has higher hardness and Young's modulus than the nonpolar GaN. Cathodoluminescence and transmission electron microscopy characterizations of indent-induced plastic deformation reveal that there are two primary slip systems for the c-plane GaN, while there is only one most favorable slip system for the nonplane GaN. We suggest that the anisotropic elasto-plastic mechanical properties of GaN are relative to its anisotropic plastic deformation behavior