Where Is the Lightest Charmed Scalar Meson?

Area of Science:

• Particle Physics
• Hadron Spectroscopy
• Quantum Chromodynamics

Background:

• The D_{0}^{*}(2300) is the lightest observed charmed scalar meson.
• Previous analyses of B meson decays have relied on this assignment.
• Modern B factories and LHCb experiments provide high-precision data.

Purpose of the Study:

• To re-evaluate the properties of the lightest charmed scalar meson.
• To analyze the decay B^{-}→D^{+}π^{-}π^{-} using precise LHCb data.
• To ensure consistency with fundamental principles like chiral symmetry and unitarity.

Main Methods:

• Analysis of LHCb data for the B^{-}→D^{+}π^{-}π^{-} decay.
• Application of an unitarized chiral amplitude model.
• Model-independent extraction of the low-energy S-wave Dπ phase.

Main Results:

• The parameters of the D_{0}^{*}(2300) are in conflict with LHCb data.
• A lighter charmed scalar meson, D_{0}^{*}(2100), provides a good description of the data.
• The difference between decay and scattering Dπ phases is attributed to ρ^{-} exchange.

Conclusions:

• The lightest charmed scalar meson is likely lighter than D_{0}^{*}(2300).
• Accurate extraction of heavy meson properties requires methods respecting chiral symmetry, unitarity, and analyticity.
• This finding is analogous to studies of light scalar mesons.