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