π → lνγ form factors at two-loop

lνγ Form Factors at Two - loop

Within Chiral Perturbation Theory (CHPT) we compute the form factors A, V and γ = A/V in the π → lνγ decay to O(p 6).

Two-Loop Form Factors in QED

We evaluate the on shell form factors of the electron for arbitrary momentum transfer and finite electron mass, at two loops in QED, by integrating the corresponding dispersion relations, which involve the imaginary parts known since a long time. The infrared divergences are parameterized in terms of a fictitious small photon mass. The result is expressed in terms of Harmonic Polylogarithms of ...

1 The form factors of ωπ 0 and π + π − at ψ(2S)

The form factors of ωπ 0 and π + π − at ψ(2S)

Form Factors for B → π and D → π Transitions

Armed with the information on the form factor f + (0) inferred from recent CLEO measurements of SU(3)-breaking effects in charmed meson decays, we have studied the form factor f + . In the heavy quark limit, f Bπ + (q ) is related to f + (q ) in the kinematic region close to zero recoil. Assuming pole dominance for its q dependence, f + (0) is estimated to be ≈ 0.39 . If the requirement of heav...