Contribution of constituent quark model cs¯ states to the dynamics of the Ds0∗(2317) and Ds1(2460) resonances

Abstract

The masses of the Ds0∗(2317) and Ds1(2460) resonances lie below the DK and D∗K thresholds respectively, which contradicts the predictions of naive quark models and points out to non-negligible effects of the D(∗)K loops in the dynamics of the even-parity scalar (Jπ= 0 +) and axial-vector (Jπ= 1 +) cs¯ systems. Recent lattice QCD studies, incorporating the effects of the D(∗)K channels, analyzed these spin-parity sectors and correctly described the Ds0∗(2317)-Ds1(2460) mass splitting. Motivated by such works, we study the structure of the Ds0∗(2317) and Ds1(2460) resonances in the framework of an effective field theory consistent with heavy quark spin symmetry, and that incorporates the interplay between D(∗)K meson–meson degrees of freedom and bare P-wave cs¯ 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 D(∗)K two-meson components in the Ds0∗(2317) and Ds1(2460) 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 cs¯ constituent quark model patterns.