Abstract
It is demonstrated that, if the lightest positive parity charm mesons are assumed to owe their existence to non-perturbative Goldstone boson-D/D∗ scattering, various puzzles in the charm meson spectrum get resolved. Most importantly the ordering of the lightest strange and non-strange scalars becomes natural. Furthermore, it is demonstrated that the amplitudes for Goldstone boson-D/D∗ scattering are fully consistent with the high quality data on decay B−→ D+π−π− provided by LHCb. It implies that the lowest positive-parity charm mesons are dynamically generated rather than quark-antiquark states.
Highlights
Understanding the nonperturbative aspects of the QCD is one of the most challenging problems in physics
Until the beginning of the millennium heavy-hadron spectroscopy was assumed to be well understood by the conventional quark model which describes the positive-parity ground-state charm mesons as bound systems of a heavy quark and a light antiquark in a P-wave
Since attempts to adjust the quark model to adapt the two new states is at odds with previous expectations and raises new puzzles [5], various interpretations of the nature of the D∗s0(2317) and the Ds1(2460) were proposed, including D(∗)K hadronic molecules [6,7,8], tetraquark [9, 10], and chiral partners [11, 12]
Summary
Understanding the nonperturbative aspects of the QCD is one of the most challenging problems in physics. Until the beginning of the millennium heavy-hadron spectroscopy was assumed to be well understood by the conventional quark model which describes the positive-parity ground-state charm mesons as bound systems of a heavy quark and a light antiquark in a P-wave. A theoretical framework satisfying such requirements is provided by the unitarized chiral perturbation theory (ChPT) for charmed mesons, see e.g. Refs.
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