  In recent years many candidates for states beyond the most simple realization
of the quark model were found in various experiments around the world. However,
so far no consensus exists on their structure, although there is strong
evidence that at least some of those are dynamically generated from meson-meson
interactions. In this Letter we provide an important missing piece from the
theoretical side to prove that the lightest open charm strange and non-strange
scalars $D_{s0}^*(2317)$ and $D_0^*$ as well as their axial-vector partner
states can all be understood as emerging from the interactions between
Goldstone bosons stemming from the spontaneous breaking of chiral symmetry and
the ground state charmed mesons. For that purpose we exploit the flavor
multiplet structure of the lightest open-charm positive-parity scalar states in
an SU(3) symmetric lattice QCD simulation at large pion masses to establish
that there exists a bound state in the flavor-sextet representation, which
cannot emerge for quark-antiquark states but appears naturally for four-quark
configurations. Moreover, we find repulsion in the $[15]$ representation and
thus no single-particle state in this representation exists, falsifying the
expectation for tetraquark models. The findings establish the pattern predicted
for the interactions of Goldstone bosons with $D$ mesons from chiral symmetry
and the paradigm of the lowest-lying positive-parity charmed mesons as
dynamically generated states.
