The scalar exotic resonances X(3915), X(3960), X0(4140)

The scalar resonances X(3915), X(3960), X-0(4140) are considered as exotic four-quark states: cq (c) over bar(q) over bar, cs (c) over bar(s) over bar, cs (c) over bar(s) over bar, while the X(3863) is proved to be the c (c) over bar, 2(3) P-0 state. The masses and the widths of these resonances are calculated in the framework of the Extended Recoupling Model, where a four-quark system is formed inside the bag and has relatively small size (less than or similar to 1.0 fm). Then the resonance X(3915) appears due to the transitions: J/psi omega into D*(+) D*(-) (or D*(0) (D) over bar*(0)) and back, while the X(3960) is created due to the transitions D-s(+) D-s(-) into J/psi phi and back, and the X-0(4140) is formed in the transitions J/psi phi into D*(+)(s) D*(-)(s) and back. The characteristic feature of the recoupling mechanism is that this type of resonances can be predominantly in the S-wave decay channels and has J(P) = 0(+). In two-channel case the resonance occurs to be just near the lower threshold, while due to coupling to third channel (like the c (c) over bar channel) it is shifted up and lies by (20-30) MeV above the lower threshold. The following masses and widths are calculated: M(X(3915)) = 3920 MeV, Gamma(X(3915)) = 20 MeV; M(X(3960)) = 3970 MeV, Gamma( X(3960) = 45(5) MeV, M(X-0(4140)) = 4120(20) MeV, Gamma(X-0(4140)) = 100 MeV, which are in good agreement with experiment.

Automated summary

This article studies the masses and widths of the scalar resonances X(3915), X(3960), X-0(4140), and X(3863), and calculates their values using the Extended Recoupling Model, which are in good agreement with experimental data.