Heavy-flavor-conserving hadronic weak decays of heavy baryons

摘要

A bstract More than two decades ago, we studied heavy-flavor-conserving weak decays of heavy baryons within the framework that incorporates both heavy-quark and chiral symmetries. In view of the first observation of Ξ ~( b ) _(?) ?→?Λ ~( b ) _(0) π _(?) by LHCb recently, we have reexamined these decays and presented updated predictions. The predicted rates for Ξ ~( b ) _(?) ?→?Λ ~( b ) _(0) π _(?) in the MIT bag and diquark models are consistent with experiment. The major theoretical uncertainty stems from the evaluation of baryon matrix elements. The branching fraction of Ξ~( c ) → Λ~( c ) π is predicted to be of order 10_(?4). It is suppressed relative to ? Ξ b → Λ b π $$ mathrm{mathcal{B}}left({Xi}_bo {Lambda}_bpi ight) $$ owing to the shorter lifetime of Ξ~( c ) relative to Ξ~( b ) and the destructive nonspectator W -exchange contribution. The kinematically accessible weak decays of the sextet heavy baryon Ω~( Q ) are Ω~( Q ) → Ξ~( Q ) π . Due to the absence of the ? 6 ? ? 3 ? $$ {mathrm{mathcal{B}}}_6-{mathrm{mathcal{B}}}_{{}_3^{-}} $$ transition in the heavy quark limit and the ? 6 ? ? 6 $$ {mathrm{mathcal{B}}}_6-{mathrm{mathcal{B}}}_6 $$ transition in the model calculations, Ω~( Q ) → Ξ~( Q ) π vanish in the heavy quark limit.