Understanding the hadron spectrum is one of the premier challenges in particle
physics. For a long time, the quark model has served as an ordering scheme and brought systematics into the hadron zoo. However, many new hadrons that were observed since 2003, including the lowest-lying positive-parity charm-strange mesons Ds0(2317) and Ds1(2460), do not conform with quark model expectations. In this talk, I will explain how various puzzles in the spectrum of the positive-parity charm mesons find a natural resolution using inputs from chiral dynamics and lattice QCD. I will show that there should be two scalar charm mesons instead of the D0(2400) listed in the Review of Particle Physics, and demonstrate that such a scenario is fully consistent with recent high quality data on the B -> D pi pi provided by the LHCb experiment. By using an approximate symmetry, I will then make predictions on the spectrum of negative-parity doubly charm baryons.
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