Precision calculations of the D₍ₛ₎D₍ₛ₎V and B₍ₛ₎B₍ₛ₎V couplings from light-cone sum rules

We present an improved calculation of the $HHV$ (H=D₍ₛ₎,\, B₍ₛ₎, V= ρ, K^, ω, and φ) coupling constants gHHV beyond leading order in αₛ from QCD light-cone sum rules (LCSRs) by means of the light-cone distribution amplitudes (LCDAs) of light vector mesons. Near the light-cone, the next-to-leading order QCD corrections for the vacuum-to-vector-meson correlation function are included at leading power in δV = mV/mQ ($Q=b,c$) within the framework of hard-collinear factorization. The higher-twist corrections from two-particle and three-particle vector meson LCDAs are systematically incorporated at leading order in αₛ by applying the method of background field in LCSRs. Based on these improvements, we perform a systematic computation of the strong coupling constants gH HV and extract the effective coupling β of the heavy meson chiral perturbation theory (HMχPT). Furthermore, we accomplish the analysis for the relation between the coupling gHHV and the residue of the H→ V transition form factor A₀ at heavy pseudoscalar pole. Additionally, we provide a detailed investigation of the $SU(3)$ flavour symmetry breaking effects and conduct a comparative analysis with results from previous studies.