Is d∗(2380)d^*(2380) a compact hexaquark state?

The most fascinating dibaryon in the non-strange quark sector is $d^*(2380)$, which was reported by WASA-at-COSY Collaboration and confirmed by A2@MAMI Collaboration. The reported mass and width are $M\approx2.37$ GeV, $\Gamma\approx70$ MeV and the quantum numbers $IJ^P=03^+$. The structure of $d^*(2380)$ is still in controversy. In the present calculation, the powerful method in few-body system, Gaussian expansion method is employed to explore the structure of $d^*(2380)$ in the framework of constituent quark models without assuming the presupposed structure. The results show that the radius of $d^*(2380)$ is around 0.7 fm, a very compact object. Because of the compact structure, the color singlet-singlet component has a large overlap with the color octet-octet one, two colorless, large overlapped $\Delta$s dominate the state is possible.Comment: 7 pages, 8 table

Age-period-cohort effects on the development of cognitive impairment among the elderly

The objectives of the study were to investigate the effects of age, calendar period, and birth cohort on the development of cognitive impairment among the elderly, and to identify factors possibly moderating these effects. Harmonized data were drawn from two community-based cohort studies. A total of 3,021 participants, born after 1895, age 65 years or older with normal cognitive capacities were recruited during 1987-2008 and followed for more than 10 years. Cognitive capability was evaluated periodically using the Clinical Dementia Rating (CDR) scale. Incident mild cognitive impairment (MCI) was defined as the CDR value reaching 0.5. Age-period-cohort (APC) modelling approach was used to evaluate three time-varying effects on the development of MCI. Confounding and moderating effects of gender, education, and ApoE4 allele were also examined. Our analysis results showed that age was the most significant time-dependent factor affecting the MCI incident rates. Within the same calendar period and birth cohort, the MCI rate in the older elderly was significantly higher compared with the younger elderly population. A significant period effect was observed in which the MCI incidence rates were decreasing from the period of 1990-1994 through 2015 after controlling for age and birth cohort. No significant cohort effect was found. Gender showed no significant confounding or moderating effects. The age effects on MCI incidence rate was not moderated or confounded by education, while the period effects were significantly confounded by education. The cohort effect was significantly moderated by education. The cohort effects on MCI incidence rates for individuals who received HS education or higher education were different depending on the levels of education. ApoE4 allele did not show a significant moderating effect. Public Health Significance The APC model shows advantages over the traditional modelling approaches as it dissects the independent effects of age, period, and cohort. For public health, chronic disease prevalence often reflects a combination of processes that vary by these three factors. Better understanding the impacts of these time-dependent factors on disease rates help to guide hypotheses about etiologic mechanisms, and more importantly, guides researchers in conducting and presenting surveillance with the best practices

The explanation of some exotic states in the cscˉsˉcs\bar{c}\bar{s} tetraquark system

Inspired by the recent observation of $\chi_{c0}(3930)$, $X(4685)$ and $X(4630)$ by the LHCb Collaboration and some exotic resonances such as $X(4350)$, $X(4500)$, etc. by several experiment collaborations, the $cs\bar{c}\bar{s}$ tetraquark systems with $IJ^{P}=00^+$, $01^+$ and $02^+$ are systematically investigated in the framework of the quark delocalization color screening model(QDCSM). Two structures, the meson-meson and diquark-antidiquark structures, as well as the channel-coupling of all channels of these two configurations are considered in this work. The numerical results indicate that the molecular bound state $\bar{D}_{s}D_{s}$ with $IJ^{P}=00^+$ can be supposed to explain the $\chi_{c0}(3930)$. Besides, by using the stabilization method, several resonant states are obtained. There are four $IJ^{P}=00^{+}$ states around the resonance mass 4035 MeV, 4385 MeV, 4524 MeV, and 4632 MeV, respectively; one $IJ^{P}=01^{+}$ state around the resonance mass 4327 MeV; and two $IJ^{P}=02^{+}$ states around the resonance mass 4419 MeV and 4526 MeV, respectively. All of them are compact tetraquarks. Among these states, $X(4350)$, $X(4500)$ and $X(4700)$ can be explained as the compact tetraquark state with $IJ^{P}=00^{+}$, and the $X(4274)$ is possible to be a candidate of the compact tetraquark state with $IJ^{P}=01^{+}$. More experimental tests are expected to check the existence of all these possible resonance states.Comment: 10 pages, 3 figure