Measurement of the branching fractions of doubly Cabibbo-suppressed D decays

By analyzing e⁺e⁻ collision data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector, corresponding to an integrated luminosity of 20.3 fb⁻¹, we measure the branching fractions of the doubly Cabibbo-suppressed (DCS) decays D⁰→ K⁺π⁻, D⁰→ K⁺π⁻π⁻π⁺, D⁰→ K⁺π⁻π⁰, D⁰→ K⁺π⁻π⁰π⁰, D⁺→ K⁺π⁺π⁻, and D⁺→ K⁺K⁺K⁻. We also perform the first searches for D⁰→ K⁺π⁻η, D⁰→ K⁺π⁻π⁰η, D⁺→ K⁺π⁺π⁻η, D⁺ → K⁺ (π⁺π⁻η)_non−η′, and D⁺ → K⁺ηη and report the first observations and evidence for some of these final states. Combining the measurements with the world averages of the corresponding Cabibbo-favored (CF) decays, the ratios of the DCS/CF branching fractions are obtained. For the D⁺ → K⁺ (π⁺π⁻η)_non−η′ decay, the ratio is significantly larger than the corresponding ratios of the other DCS decays.