Analysis Of The Y(4140) And Related Molecular States With QCD Sum Rules

Recently the CDF Collaboration observed a narrow structure (which is denoted as the Y ( 4140) now) near the J /ψφthreshold. The narrow structure Y ( 4140) is very similar to the charmonium-like Y ( 3930) near the J /ψωthreshold. There have been several explanations for the narrow structure Y ( 4140), such as a Ds * Ds * molecular, an exotic ( J PC= 1?+) hybrid charmonium, a ccss teraquark state, or the effect of the J /ψφthreshold. In order to identify the Y ( 4140) as a Ds * Ds * molecular state, we must prove that its mass lies in the region ( 4.1 ? 4.2 )GeV. In this article, we assume that there exist scalar D * D *, Ds * Ds *, B * B *and Bs * Bs * molecular states, and study their masses using QCD sum rules. The numerical results indicate that the masses are about ( 250 ? 500 )MeVabove the corresponding D * ? D*, Ds * ? Ds*, B * ? B*and Bs * ? Bs*thresholds. The Y ( 4140) is unlikely a scalar Ds * Ds * molecular state. The scalar D * D *, Ds * Ds *, B * B * and Bs * Bs * molecular states maybe not exist, while the scalar D′* D′* , Ds′* Ds′* , B′* B′* and * *Bs′Bs′molecular states maybe exist.