Phys. Rev. D 80, 076006 (2009) [12 pages]Pion electroproduction amplitude relations in the 1/Nc expansionReceived 8 May 2009; published 16 October 2009 We derive expressions for pion electroproduction amplitudes in the 1/Nc expansion of QCD, and obtain from them linear relations between the electromagnetic multipole amplitudes that hold at all energies. The leading-order relations in 1/Nc compare favorably with available data (especially away from resonances), but the next-to-leading-order relations tend to provide only small or no improvement. © 2009 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevD.80.076006
DOI:
10.1103/PhysRevD.80.076006
PACS:
11.15.Pg, 13.60.Le, 25.30.Rw
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