Hard- and soft-gluonic effects in charmed-baryon decays

Abstract

The QCD-enhanced effective weak hamiltonian for the Weinberg-Salam model including hardgluonic corrections is used to calculate the experimentally measured ratio$\Gamma (\Lambda _c^ + \to p\bar K^0 )/\Gamma (\Lambda _c^ + \to \Lambda \pi ^ + )$. The same effective weak hamiltonian was used to describeD→K π decays. In these decays, it failed; agreement with experiments was possible only when some soft-gluonic effects were included. The same situation is encountered in charmed-baryon decays. Predictions are also given for theΛ ⁺ _c →Ξ ⁰ K ⁺,Λ ⁺ _c →Λ ⁺⁺ K ⁻ and$\Lambda _c^ + \to \Lambda ^ + \bar K^0$ decays.