https://doi.org/10.1140/epjc/s10052-018-6176-3
Regular Article - Theoretical Physics
Contribution of constituent quark model 
states to the dynamics of the 
and 
resonances
1
Departamento de Física, Universidad de Murcia, 30071, Murcia, Spain
2
Instituto de Física Corpuscular (IFIC), CSIC-Universidad de Valencia, 46071, Valencia, Spain
3
Grupo de Física Nuclear, Universidad de Salamanca, 37008, Salamanca, Spain
* e-mail: pedro.fernandez@ific.uv.es
Received:
18
May
2018
Accepted:
23
August
2018
Published online:
6
September
2018
The masses of the 
and resonances lie below the DK and 
thresholds respectively, which contradicts the predictions of naive quark models and points out to non-negligible effects of the 
loops in the dynamics of the even-parity scalar (
) and axial-vector (
) systems. Recent lattice QCD studies, incorporating the effects of the channels, analyzed these spin-parity sectors and correctly described the 
mass splitting. Motivated by such works, we study the structure of the and resonances in the framework of an effective field theory consistent with heavy quark spin symmetry, and that incorporates the interplay between meson–meson degrees of freedom and bare P-wave states predicted by constituent quark models. We extend the scheme to finite volumes and fit the strength of the coupling between both types of degrees of freedom to the available lattice levels, which we successfully describe. We finally estimate the size of the two-meson components in the and resonances, and we conclude that these states have a predominantly hadronic-molecular structure, and that it should not be tried to accommodate these mesons within constituent quark model patterns.
© The Author(s), 2018
