Systematic analysis of D (ₒ) meson semi-leptonic decays in the covariant light-front quark model

Abstract The weak decays of the D (ₒ) D (s) meson provide a pivotal platform to advance our understanding of the Standard Model (SM) and to explore New Physics (NP). In recent years, experiments have collected a significant amount of data on the D (ₒ) D (s) meson decays, particularly from BESIII, which provides substantial support for theoretical research. In this work, we systematically investigate the semi-leptonic decays of D (ₒ) D (s) meson to pseudoscalar (P), scalar (S), vector (V), and axial-vector (A) mesons within the framework of the covariant light-front quark model (CLFQM). We calculate the form factors of the transitions D (ₒ) P, S, V, A D (s) → P, S, V, A and the branching ratios of the corresponding semi-leptonic decays, then compare them with experimental data and results from other theoretical models. The form factor values of the transitions D (ₒ) P, V D (s) → P, V obtained from the CLFQM are consistent with those of other theoretical models and available data in most cases. However, significant discrepancies are found in some specific D (ₒ) S, A D (s) → S, A transitions, such as D a₀ (980), a₀ (1450) D → a 0 (980), a 0 (1450) and D (ₒ) K₁₁ D (s) → K 1 B, compared to other theoretical calculations. The predicted branching ratios for the semi-leptonic decays D P (V) _ D → P (V) ℓ ν</m