Weak Decays of Doubly Heavy Baryons: the $1/2\to 1/2$ case

Abstract

Very recently, the LHCb collaboration has observed in the final state $Λ_c^+ K^-π^+π^+$ a resonant structure that is identified as the doubly-charmed baryon $Ξ_{cc}^{++}$. Inspired by this observation, we investigate the weak decays of doubly heavy baryons $Ξ_{cc}^{++}$, $Ξ_{cc}^{+}$, $Ω_{cc}^{+}$, $Ξ_{bc}^{(\prime)+}$, $Ξ_{bc}^{(\prime)0}$, $Ω_{bc}^{(\prime)0}$, $Ξ_{bb}^{0}$, $Ξ_{bb}^{-}$ and $Ω_{bb}^{-}$ and focus on the decays into spin $1/2$ baryons in this paper. At the quark level these decay processes are induced by the $c\to d/s$ or $b\to u/c$ transitions, and the two spectator quarks can be viewed as a scalar or axial vector diquark. We first derive the hadronic form factors for these transitions in the light-front approach and then apply them to predict the partial widths for the semi-leptonic and non-leptonic decays of doubly heavy baryons. We find that a number of decay channels are sizable and can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC.