Pion Photoproduction Amplitude Relations in the 1/N_c Expansion
High Energy Physics - Phenomenology
2009-11-10 v1
Abstract
We derive expressions for pion photoproduction amplitudes in the 1/N_c expansion of QCD, and obtain linear relations directly from this expansion that relate electromagnetic multipole amplitudes at all energies. The leading-order relations in 1/N_c compare favorably with available data, while the next-to-leading order relations seem to provide only a small improvement. However, when resonance parameters are compared directly, the agreement at O(1/N_c) or O(1/N_c^2) is impressive.
Keywords
Cite
@article{arxiv.hep-ph/0412294,
title = {Pion Photoproduction Amplitude Relations in the 1/N_c Expansion},
author = {Thomas D. Cohen and Daniel C. Dakin and Richard F. Lebed and Daniel R. Martin},
journal= {arXiv preprint arXiv:hep-ph/0412294},
year = {2009}
}
Comments
19 pages, ReVTeX, 50 eps files combine into 5 compound figures