TY  - JOUR
AU  - Matuschek, Inka
AU  - Baru, Vadim
AU  - Guo, Feng-Kun
AU  - Hanhart, Christoph
TI  - On the nature of near-threshold bound and virtual states
JO  - The European physical journal / A
VL  - 57
IS  - 3
SN  - 1434-601X
CY  - Heidelberg
PB  - Springer
M1  - FZJ-2021-01508
SP  - 101
PY  - 2021
AB  - Physical states are characterised uniquely by their pole positions and the corresponding residues. Accordingly, in those parameters also the nature of the states should be encoded. For bound states (poles on the real s-axis below the lowest threshold on the physical sheet) there is an established criterion formulated originally by Weinberg in the 1960s, which allows one to estimate the amount of compact and molecular components in a given state. We demonstrate in this paper that this criterion can be straightforwardly extended to shallow virtual states (poles on the real s-axis below the lowest threshold on the unphysical sheet) which should be classified as molecular. We argue that predominantly non-molecular or compact states exist either as bound states or as resonances (poles on the unphysical sheet off the real energy axis) but not as virtual states. We also discuss the limitations of the mentioned classification scheme.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000631879900003
DO  - DOI:10.1140/epja/s10050-021-00413-y
UR  - https://juser.fz-juelich.de/record/891423
ER  -