1/N_c Corrections in Meson-Baryon scattering

Abstract

We develop expressions that organize s-channel meson-baryon scattering amplitudes according to the 1/N c expansion of QCD. The vector operator ∆ ≡ J t −I t (the difference of t-channel isospin and spin exchange quantum numbers), which parametrizes the 1/N c corrections, is here shown to equal K ′ − K, the difference between s-channel final-and initial-state "grand spin" quantum numbers. We derive the full expression describing scattering in the s channel, which is a complete parametrization of the amplitude to all orders in 1/N c .

Pion electroproduction amplitude relations in the1/Ncexpansion

“…The expression of these pion-baryon constraints in terms of s-channel observables is explored in Refs. [22].…”

“…[19] showed that static pion-baryon couplings with I = J are suppressed by a relative factor of 1/N s-channel observables is explored in Refs. [22].…”