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arXiv · hep-ph/0308303

Spectator interactions and factorization in B -> pi ell nu decay

M. Beneke·Th. Feldmann
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Abstract

We investigate the factorization of different momentum modes that appear in matrix elements for exclusive B meson decays into light energetic particles for the specific case of B -> pi form factors at large pion recoil. We first integrate out hard modes with virtualities of order m_b^2 (m_b being the heavy quark mass), and then hard-collinear modes with virtualities m_b Lambda (Lambda being the strong interaction scale). The resulting effective theory contains soft and collinear fields with virtualities Lambda^2. We prove a previously conjectured factorization formula for B -> pi form factors in the heavy quark limit to all orders in alpha_s, paying particular attention to `endpoint singularities' that might have appeared in hard spectator interactions.

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M. Beneke, Th. Feldmann. 2003-08-28. Spectator interactions and factorization in B -> pi ell nu decay. https://doi.org/10.1140/epjcd%2Fs2003-03-121-6

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