Factorization of heavy-to-light baryonic transitions in SCET

In the framework of the soft-collinear effective theory, we demonstrate that the leading-power heavy-to-light baryonic form factors at large recoil obey the heavy quark and large energy symmetries. Symmetry breaking effects have several origins but all of them are suppressed by Λ/mb or Λ/E, where Λ is the hadronic scale, mb is the b quark mass and E∝mb is the energy of light baryon in the final state. Including the energy release dependence, we derive the scaling law for form factors ξΛ,p∝Λ2 /E2, which is in accordance with the implication from the experimental measurement on the branching ratio of Λb → pπ-. At leading order in αs, the leading-power baryonic form factors can factorize into the soft and collinear matrix elements without encountering any divergence. A leading-power factorization formula for nonleptonic b-baryon decays is also established. (orig.)