Measurements of the absolute branching fractions of the doubly Cabibbo-suppressed decays D⁺→ K⁺π⁰, D⁺→ K⁺η and D⁺→ K⁺η^

Using 20.3\, fb⁻¹ of e⁺e⁻ collision data collected at a center-of-mass energy of 3.773\,GeV with the BESIII detector, we present improved measurements of the absolute branching fractions of the doubly Cabibbo-suppressed decays D⁺→ K⁺π⁰, D⁺→ K⁺η and D⁺ → K⁺ η^ with the double-tag method. The statistical significance of each signal decay exceeds $10σ$. The branching fractions are determined to be B(D⁺→ K⁺ π⁰) = (1.45 ± 0.06 ± 0.06)× 10⁻⁴, B(D⁺→ K⁺ η) = (1.17 ± 0.10 ± 0.03)× 10⁻⁴ and B(D⁺→ K⁺ η^) = (1.88 ± 0.15 ± 0.06)× 10⁻⁴, where the first uncertainties are statistical and the second systematic. These results are consistent with the world average values but with significantly improved precision.