Factorization in leptonic radiative B -> gamma eν decays

We discuss factorization in exclusive radiative leptonic B->\gamma e\nu decays using the soft-collinear effective theory. The form factors describing these decays can be expanded in a power series in Lambda/E_\gamma with E_\gamma the photon energy. We write down the most general operators in the effective theory which contribute to the form factors at leading order in Lambda_QCD/E_\gamma, proving their factorization into hard, jet and soft contributions, to all orders in alpha_s.