Analysis the f0(980)f_0(980) and a0(980)a_0(980) mesons as four-quark states with the QCD sum rules

In this article, we take the point of view that the scalar mesons $f_0(980)$ and $a_0(980)$ are diquark-antidiquark states $(qq)_{\bar{3}}(\bar{q}\bar{q})_3$, and devote to determine their masses in the framework of the QCD sum rules approach with the interpolating currents constructed from scalar-scalar type and pseudoscalar-pseudoscalar type diquark pairs respectively. The numerical results indicate that the scalar mesons $f_0(980)$ and $a_0(980)$ may have two possible diquark-antidiquark substructures.Comment: 8 pages, 1 figure, revised versio

Bis[1-(4-chloro­benz­yl)pyridinium] bis­(1,2,5-thia­diazole-3,4-dithiol­ato)nickelate(II)

The asymmetric unit of the salt, (C12H11ClN)2[Ni(C2N2S3)2], comprises one cation and a half of Ni(tdas)2 (tdas = 1,2,5-thia­diazole-3,4-dithiol­ate) anion. The NiII atom is located at a centre of inversion. The NiII atom has a square-planar coordination with Ni—S distances of 2.2052 (4) and 2.1970 (5) Å. In crystal, weak C—H⋯S and C—H⋯Ni contacts are observed between the anions and cations