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.
|Original language||English (US)|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|State||Published - Oct 16 2009|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)