gamma production in p 20Ne and pN interactions at 300 GeV.

Data on the multiplicity and inclusive spectra of {gamma} produced in inelastic {ital p} {sup 20}Ne and {ital pN} interactions at 300 GeV are presented. The {gamma} multiplicity for {ital p} {sup 20}Ne interactions is 11.43{plus minus}0.23, and the ratio of {l angle}{ital n}{sub {gamma}}{r angle} for {ital p} {sup 20}Ne and {ital pN} interactions is 1.48{plus minus}0.05. From an analysis of the effective-mass distributions, {l angle}{ital n}{sub {pi}}{sup 0}{r angle}=4.91{plus minus}0.52 and {l angle}{ital n}{sub {eta}}{sup 0}{r angle}=1.47{plus minus}0.33. In fact, {eta}{sup 0} production is much higher in {ital p} {sup 20}Ne interactions ({ital R}({eta}{sup 0}/{pi}{sup 0})=0.66{plus minus}0.12 for {ital n}{sub {ital p}}{ge}2) than in {ital pN} interactions ({ital R}({eta}{sup 0}/{pi}{sup 0}) =0.06{plus minus}0.04). No {eta}{prime}(958) signal is seen. Strong correlations between {l angle}{ital n}{sub {gamma}}{r angle} and {ital n}{sub {ital p}}, the number of secondary protons, are observed, primarily from the central and target fragmentation regions. Inclusive {ital y}{sup *} and {ital p}{sub {perpendicular}} spectra are analyzed and evidence for low-energy cascading and rescattering of fast particles in the projectile fragmentation region is discussed. The data are compared to the predictions of the additive quark model, the Lund model, and the dual parton model.