D-Meson Spectra, Their Strong Decays and M1 Transitions

The present study provides an extensive investigation of the mass spectra, and their strong decays and M1 transitions, of D-mesons in a Relativistic Independent Quark Model (RIQM). The quark–antiquark interaction is described by an equal components of scalar and vector potentials of square-root form, supplemented with essential corrections arising from center-of-mass motion, gluon-exchange effects, and pionic contributions. These refinements enable accurate reproduction of the ground- and excited-state masses, which exhibit reasonable agreement with experimental and lattice QCD results. The radial and orbital excitations, covering the 5S, 3P, and 3D states, have been systematically computed. The obtained spin-averaged masses and fine-structure splitting correspond closely with those reported by PDG and LHCb. Employing the momentum-space wave functions, the pseudoscalar and vector decay constants are evaluated, yielding results reasonably consistent with those obtained from lattice QCD and QCD sum-rule calculations. The two-body strong decay widths of various charmed resonances are evaluated through the Heavy Quark Effective Theory (HQET) in combination with the chiral Lagrangian approach. The magnetic-dipole (M1) transitions are also examined. The predicted strong decay widths for highly excited states follow the observed experimental and theoretical results. Additionally, the vector–pseudoscalar–pseudoscalar (VPP) coupling constants are extracted, offering valuable understanding of meson–meson interaction. Overall, the consistency of the present results indicates that this relativistic potential model provides a phenomenologically consistent description of the spectroscopic and decay properties of heavy–light D-mesons.