Observation of D-s(+) -> p(n)over-bar and confirmation of its large branching fraction

Abstract

The baryonic decay D-s(+) -> p (n) over bar is observed, and the corresponding branching fraction is measured to be (1.21 +/- 0.10 +/- 0.05) x 10(-3), where the first uncertainty is statistical and second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII e(+)e(-) double-ring collider with a center-of-mass energy of 4.178 GeV and an integrated luminosity of 3.19 fb(-1). The result confirms the previous measurement by the CLEO Collaboration and is of greatly improved precision. This result will improve our understanding of the dynamical enhancement of the W-annihilation topology in the charmed meson decays.