Analysis of $D$+ → $K¯$0$e$+$ν$$e$ and $D$+ → $π$0$e$+$ν$$e$ semileptonic decays

Using 2.93 fb–1 of data taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we study the semileptonic decays D+ → K¯0e+νe and D+ → π0e+νe. Here, we measure the absolute decay branching fractions B(D+ → K¯0e+νe) = (8.60 ± 0.06 ± 0.15) × 10–2 and B(D+ → π0e+νe) = (3.63 ± 0.08 ± 0.05) × 10–3, where the first uncertainties are statistical and the second systematic. We also measure the differential decay rates and study the form factors of these two decays. With the values of |Vcs| and |Vcd| from Particle Data Group fits assuming CKM unitarity, we obtain the values of the form factors at q2 = 0, $f$ $^{K}_{+}$(0) = 0.725 ± 0.004 ± 0.012 and $f$ $^{π}_{+}$(0) = 0.622 ± 0.012 ± 0.003. Taking input from recent lattice QCD calculations of these form factors, we determine values of the CKM matrix elements |Vcs| = 0.944 ± 0.005 ± 0.015 ± 0.024 and |Vcd| = 0.210 ± 0.004 ± 0.001 ± 0.009, where the third uncertainties are theoretical.