Isovector unpolarized quark distribution in the nucleon in the large-N-c limit - art. no. 034024

We calculate the isovector (flavor-nonsinglet) unpolarized quark and antiqu ark distributions in the nucleon at a low normalization point in the large- N-c limit. The nucleon is described as a soliton of the effective chiral th eory. The isovector distribution appears in the next-to-leading order of th e 1/N-c expansion. Numerical results for the quark and antiquark distributi ons compare well with the parametrizations of the data at a low normalizati on point. This large-N-c approach gives a flavor asymmetry of the antiquark distribution (violation of the Gottfried sum rule) in good agreement with the measurements. [S0556-2821(99)01701-4].