Speaker
Description
Starting with the discovery of the $X(3872)$ in 2003, evidence for many exotic states beyond explanations within the quark model have been found in experiments worldwide. Many of those states are close to thresholds of two combined open-flavor states with convenient quantum numbers, such that the data suggests a treatment as a composite system, namely a hadronic molecule. In the talk, research for the case of $Z_b(10610)$ and $Z_b(10650)$ will be examined. Calculations using HQET and $\chi$PT that might disclose the molecular nature of a composite $B^{(*)}$-$\bar{B}^{(*)}$ system will be presented. The obtained matrix elements could be used for the computation of a possible molecular binding energy and the shape of the corresponding potential well which hopefully gives insight into the internal mechanism of Z-states.
