https://doi.org/10.1140/epjc/s10052-014-3254-z
Regular Article - Theoretical Physics
Unquenched quark-model calculation of 
electromagnetic decays
1
Centro de Física Teórica de Partículas, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
2
Centro de Física das Interacções Fundamentais, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
3
Departamento de Física, Centro de Física Computacional, Universidade de Coimbra, 3004-516, Coimbra, Portugal
* e-mail: george@ist.utl.pt
Received:
6
November
2014
Accepted:
22
December
2014
Published online:
23
January
2015
A recent quark-model description of 
as an unquenched 
state is generalised by now including all relevant meson–meson configurations, in order to calculate the widths of the experimentally observed electromagnetic decays 
and 
. Interestingly, the inclusion of additional two-meson channels, most importantly 
, leads to a sizeable increase of the probability in the total wave function, although the 
component remains the dominant one. As for the electromagnetic decays, unquenching strongly reduces the 
decay rate; yet it even more sharply enhances the 
rate, resulting in a decay ratio compatible with one experimental observation but in slight disagreement with two others. Nevertheless, the results show a dramatic improvement as compared to a quenched calculation with the same confinement force and parameters. Concretely, we obtain 
keV and 
keV, with branching ratio 
.
© SIF and Springer-Verlag Berlin Heidelberg, 2015
