PT Journal
AU Baru, V
   Dong, XK
   Du, ML
   Filin, A
   Guo, FK
   Hanhart, C
   Nefediev, A
   Nieves, J
   Wang, Q
TI Effective range expansion for narrow near-threshold resonances
SO Physics Letters B
JI Phys. Lett. B
PY 2022
BP 137290
EP 7pp
VL 833
DI 10.1016/j.physletb.2022.137290
LA English
DE Effective range expansion; Exotic states; Tetraquarks; Hadronic molecules
AB We discuss some general features of the effective range expansion, the content of its parameters with respect to the nature of the pertinent near-threshold states and the necessary modifications in the presence of coupled channels, isospin violations and unstable constituents. As illustrative examples, we analyse the properties of the chi(c1)(3872) and T-cc(+) states supporting the claim that these exotic states have a predominantly molecular nature.
ER