Speaker
Description
We investigate the dynamical generation of isoscalar charmonium-like
states with a coupled-channel approach. Our focus is placed on states
with quantum numbers $J^{PC}=0^{++}$, $1^{++}$, $2^{++}$, and $3^{--}$
in the mass range of 3.6 to 4.3 GeV. We describe these systems through
effective Lagrangians constrained by heavy-quark spin-flavor and
chiral symmetries, employing an off-shell Blankenbecler-Sugar
formalism. Our study reveals six dynamically generated poles in the
complex energy plane. Among them, the experimentally observed
$\chi_{c1}(3872)$ is successfully reproduced as a bound state near the
$D\bar{D}^*$ threshold. In addition, we find a scalar ($0^{++}$)
resonance at 3861 MeV and a broader axial-vector ($1^{++}$) resonance
at 3961 MeV, alongside bound states below the $D\bar{D}$ and
$D\bar{D}^*$ thresholds. Furthermore, we identify a narrow tensor
($2^{++}$) pole at 4005 MeV and a negative-parity $\psi_3$-like
($3^{--}$) state above the $D^*\bar{D}^*$ threshold, which emerge
through dynamical coupled-channel interactions without $s$-channel
pole contributions. These results highlight the crucial role of
coupled-channel dynamics, particularly involving the $D^*\bar{D}^*$
channel, in shaping the spectrum of charmonium-like exotic states.
