Article ID Journal Published Year Pages File Type
8191081 Physics Letters B 2012 8 Pages PDF
Abstract
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 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. At leading order, the leading power baryonic form factor ξΛ,p(E), in which two hard-collinear gluons are exchanged in the baryon constituents, can factorize into the soft and collinear matrix elements convoluted with a hard-kernel of order αs2. Including the energy release dependence, we derive the scaling law ξΛ,p(E)∼Λ2/E2. We also find that this form factor ξΛ(E) is numerically smaller than the form factor governed by soft processes, although the latter is formally power-suppressed.
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Physical Sciences and Engineering Physics and Astronomy Nuclear and High Energy Physics
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