https://doi.org/10.1140/epjc/s10052-023-11590-z
Regular Article - Theoretical Physics
The scalar exotic resonances 
NRC “Kurchatov Institute”, Moscow, Russia
Received:
7
February
2023
Accepted:
4
May
2023
Published online:
16
May
2023
The scalar resonances are considered as exotic four-quark states: 
, while the X(3863) is proved to be the 
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 (
fm). Then the resonance X(3915) appears due to the transitions: 
into 
(or 
and back, while the X(3960) is created due to the transitions 
into 
and back, and the 
is formed in the transitions into 
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 
. In two-channel case the resonance occurs to be just near the lower threshold, while due to coupling to third channel (like the 
channel) it is shifted up and lies by (20–30) MeV above the lower threshold. The following masses and widths are calculated: 
MeV, 
MeV; 
MeV, 
MeV, 
MeV, 
MeV, which are in good agreement with experiment.
© The Author(s) 2023
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