Bibliographic Details
| Title: |
Photon distribution amplitudes in QCD |
| Authors: |
Ball, Patricia1 patricia.ball@durham.ac.uk, Braun, V.M.2, Kivel, N.2 |
| Source: |
Nuclear Physics B. Jan2003, Vol. 649 Issue 1/2, p263. 34p. |
| Subjects: |
Photon emission, Quantum chromodynamics |
| Abstract: |
We develop a consistent technique for the calculation of real photon emission in hard exclusive processes, which is based on the background field formalism and allows a convenient separation of hard electromagnetic and soft hadronic components of the photon. The latter ones are related to matrix-elements of light-cone operators in the electromagnetic background field and can be parametrized in terms of photon distribution amplitudes. We construct a complete set of photon distribution amplitudes up to and including twist-4, for both chirality-conserving and chirality-violating operators. The distribution amplitudes involve several non-perturbative parameters and, most importantly, the magnetic susceptibility of the quark condensate. We review and update previous estimates of the susceptibility and also give new estimates of parameters describing higher-twist amplitudes from QCD sum rules. [Copyright &y& Elsevier] |
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| Database: |
Engineering Source |
