Observation of the $W$-Annihilation Decay $D^{+}_{s} \rightarrow \omega \pi^{+}$ and Evidence for $D^{+}_{s} \rightarrow \omega K^{+}$

Abstract

We report on the observation of the W-annihilation decay Ds+→ωπ+ and the evidence for Ds+→ωK+ with a data sample corresponding to an integrated luminosity of 3.19 fb−1 collected with the BESIII detector at the center-of-mass energy s = 4.178 GeV. We obtain the branching fractions B(Ds+→ωπ+)=(1.77±0.32stat.±0.11sys.)×10−3 and B(Ds+→ωK+)=(0.87±0.24stat.±0.07sys.)×10−3, respectively.