  Different experiments have confirmed that the $D_{s0}^{\ast}(2317)$ and
$D_{s1}(2460)$ mesons are very narrow states located, respectively, below the
$DK$ and $D^{\ast}K$ thresholds. This is markedly in contrast with the
expectations of naive quark models and heavy quark symmetry. We address the
mass shifts of the $c\bar{s}$ ground states with quantum numbers $J^{P}=0^{+}$
($D_{s0}^{\ast}(2317)$) and $J^{P}=1^{+}$ ($D_{s1}(2460)$) using a
nonrelativistic constituent quark model in which quark-antiquark and
meson-meson degrees of freedom are incorporated. The quark model has been
applied to a wide range of hadronic observables and thus the model parameters
are completely constrained. We observe that the coupling of the $0^{+}$
$(1^{+})$ meson sector to the $DK$ $(D^{\ast}K)$ threshold is a key feature in
lowering the masses of the corresponding $D_{s0}^{\ast}(2317)$ and
$D_{s1}(2460)$ states predicted by the naive quark model, but also in
describing the $D_{s1}(2536)$ meson as the $1^{+}$ state of the
$j_{q}^{P}=3/2^{+}$ doublet predicted by heavy quark symmetry and thus
reproducing its strong decay properties. Two features of our formalism cannot
be address nowadays by other approaches: the coupling of the $D$-wave
$D^{\ast}K$ threshold in the $J^{P}=1^{+}$ $c\bar{s}$ channel and the
computation of the probabilities associated with different Fock components in
the physical state.
