Where Is the Lightest Charmed Scalar Meson?

The lightest charmed scalar meson is known as the D*0(2300), which is one of the earliest new hadron resonances observed at modern B factories. We show here that the parameters assigned to the lightest scalar D meson are in conflict with the precise LHCb data of the decay B-→D+π-π-. On the contrary, these data can be well described by an unitarized chiral amplitude containing a much lighter charmed scalar meson, the D*0(2100). We also extract the low-energy S-wave Dπ phase of the decay B-→D+π-π- from the data in a model-independent way, and show that its difference from the Dπ scattering phase shift can be traced back to an intermediate ρ- exchange. Our work highlights that an analysis of data consistent with chiral symmetry, unitarity, and analyticity is mandatory in order to extract the properties of the ground-state scalar mesons in the singly heavy sector correctly, in analogy to the light scalar mesons f0(500) and K*0(700). [ABSTRACT FROM AUTHOR]