Baryonic D Decay $D_s^{+}\to p\bar{n}$ and Its Implication

Abstract

The channel $D_s^{+}\to p\bar{n}$ is the only kinematically allowed baryonic D decay. It proceeds solely through the W-annihilation topology. Hence, a recent observation of this mode by CLEO will shed light on the dynamics of W-annihilation. At the short-distance level, its branching ratio is very small, of order $10^{-6}$, owing to chiral suppression. It receives long-distance contributions through final-state scattering of the leading tree and color-suppressed amplitudes. Assuming that the long-distance enhancement of W-annihilation in the baryonic D decay is similar to that in the mesonic $D_s^{+}$ decay, where the latter can be obtained from the analysis of the diagrammatic approach, we find that $D_s^{+}\to p\bar{n}$ becomes visible. The observation of this baryonic D decay implies the dynamical enhancement of the W-annihilation topology in the $D_s^{+}$ decay.

7 pages, 2 figures, one reference added, to appear in PLB