616 research outputs found

    Probing the XYZXYZ states through radiative decays

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    In this work, we have adopted the spin rearrangement scheme in the heavy quark limit and extensively investigated three classes of the radiative decays: M(bbˉ)+γ\mathfrak{M}\to (b\bar{b})+\gamma, (bbˉ)M+γ(b\bar{b})\to \mathfrak{M}+\gamma, MM+γ \mathfrak{M} \to \mathfrak{M}^\prime+\gamma, corresponding to the electromagnetic transitions between one molecular state and bottomonium, one bottomonium and molecular state, and two molecular states respectively. We also extend the same formalism to study the radiative decays of the molecular states with hidden charm. We have derived some model independent ratios when the initial or final states belong to the same spin flavor multiplet. Future experimental measurement of these ratios will test the molecular picture and explore the underlying structures of the XYZXYZ states.Comment: 21 pages, 10 tables Accepted by Phys.Rev.

    Study the Heavy Molecular States in Quark Model with Meson Exchange Interaction

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    Some charmonium-like resonances such as X(3872) can be interpreted as possible D()D()D^{(*)}D^{(*)} molecular states. Within the quark model, we study the structure of such molecular states and the similar B()B()B^{(*)}B^{(*)} molecular states by taking into account of the light meson exchange (π\pi, η\eta, ρ\rho, ω\omega and σ\sigma) between two light quarks from different mesons

    6-Isopropyl-3-phenyl-5-(p-tol­yloxy)-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one: whole-mol­ecule disorder

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    The title compound, C20H19N5O2, exhibits whole-mol­ecule disorder the refined ratios of the two components being 0.57 (2):0.43 (2). In the major component, the essentially planar [maximum deviation 0.033 (17) Å] fused pyrimidine and triazole ring system forms a dihedral angle of 10.5 (3)° with the phenyl ring, while in the minor component of disorder this angle is 27.5 (5)°. The crystal structure is stabilized by π–π stacking inter­actions between symmetry-related triazole and pyrimidine rings, with centroid–centroid distances of 3.594 (10) Å

    Genetic characterization of \u3cem\u3eToxoplasma gondii\u3c/em\u3e from pigs from different localities in China by PCR-RFLP

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    Background Toxoplasma gondii is a widely prevalent protozoan parasite that causes serious toxoplasmosis in humans and animals. The present study aimed to determine the genetic diversity of T. gondii isolates from pigs in Jiangxi, Sichuan, Guangdong Provinces and Chongqing Municipality in China using multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Methods A total of 38 DNA samples were extracted from hilar lymph nodes of pigs with suspected toxoplasmosis, and were detected for the presence of T. gondii by semi-nested PCR of B1 gene. The positive DNA samples were typed at 11 genetic markers, including 10 nuclear loci, namely, SAG1, 5′-SAG2 and 3′-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast locus Apico. Results Twenty-five of the 38 DNA samples were T. gondii B1 gene positive. Complete genotyping data for all loci could be obtained for 17 of the 25 samples. Two genotypes were revealed (ToxoDB PCR-RFLP genotypes #9 and #3). Sixteen samples belong to genotype #9 which is the major lineage in mainland China and one sample belongs to genotype #3 which is Type II variant. Conclusions To our knowledge, this is the first report of genetic typing of T. gondii isolates from pigs in Jiangxi, Sichuan Province and Chongqing Municipality, and the first report of ToxoDB #3 T. gondii from pigs in China. These results have implications for the prevention and control of foodborne toxoplasmosis in humans
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