Comment on `Gauge Invariance and k(T)-Factorization of Exclusive Processes'
Aug, 2008
5 pages
Published in:
- Phys.Lett.B 674 (2009) 182-187
e-Print:
- 0808.1526 [hep-ph]
Report number:
- DESY-09-035
View in:
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Abstract: (Elsevier)
We point out mistakes made in the one-loop calculation of some diagrams for the process πγ∗→γ in the preprint arXiv:0807.0296 , and present correct results. Especially, we have difficulty to understand their argument that a highly off-shell gluon generates a light-cone (infrared) singularity. It is shown by means of the Ward identity that the gauge-dependent light-cone singularity found in arXiv:0807.0296 does not exist. It is then shown that a hard kernel derived in the kT factorization of exclusive processes is gauge invariant and free of the light-cone singularity.Note:
- 7 pages, 5 figures, a co-author was added, new method was adopted, the conclusion remains the same
- photon pi: exclusive reaction
- singularity: light cone
- pi: wave function
- invariance: gauge
- factorization
- photon pi --> photon
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