Coupled-channel study of baryon resonances with charm

Abstract

Identifying a zero-range exchange of vector mesons as the driving force for the s-wave scattering of pseudo-scalar mesons off the baryon ground states, a rich spectrum of molecules is formed. We argue that chiral symmetry and large-$N_c$ considerations determine that part of the interaction which generates the spectrum. A bound state with exotic quantum numbers is predicted at mass 2.78 GeV. It couples strongly to the $({\bar{D}}_{s}N),(\bar{D}\Lambda ),(\bar{D}\Sigma )$ channels. A further charm minus-one system is predicted at mass 2.84 GeV as a result of $({\bar{D}}_s\Lambda ),(\bar{D}\Xi )$ interactions. The two so far observed s-wave baryons with charm one are recovered. We argue that the ${\Lambda }_c(2880)$ is not a s-wave state. In addition to those states we predict the existence of about ten narrow s-wave baryon states with masses below 3 GeV. A triplet of crypto-exotic states decaying dominantly into channels with an ${\eta }^{\prime }$ is obtained with masses 4.24 GeV and 4.44 GeV.

Comments: 5 pages, talk presented at HADRON 05