A. W. Key

EVIDENCE FOR N* RESONANCES OF MASSES 2080 AND 2190 MeV.

Abstract The spectrum of invariant mass for p π + π − π 0 combinations from π − p → π + π − π − π 0 , at 3 GeV/ c , shows peaks at 2080 and 2190 MeV. Evidence is presented to show that the 2080 enhancement decays through the ( N ∗ (1236)ϱ) channel.

Missing mass analysis of the A−2 at 6.0 GeV/c

Abstract The missing mass spectrum in the region of the A − 2 has been measured in the reaction π − p→X − p at 6.0 GeV/ c in the interval 0.27 t | c ) 2 , with an optical spark chamber system which simultaneously observed the decay X − → ηπ − . A signal of 230 events above background per five MeV interval is observed at the A 2 peak, with a signal-to-background ratio of greater than 1:1. A single D-wave Breit-Wigner distribution with a quadratic background gives a good fit to the data, yielding the parameters M 0 =(1.324±0.003) GeV/ c 2 and Γ 0 =(0.104±0.009) GeV/ c 2 . The spectrum is incompatible with a dipole shape.

A comparison of the reactions π+p → (Nπ)+π+π+π− at 4.5 GeV centre-of-mass energy

SummaryA comparative study has been made of the final states pπ+π+π−π0 and nπ+π+π+π− resulting from π+p interactions at 10.3 GeV/c incident beam momentum. Copious resonance production is seen in both final states, and evidence for production via double-diffraction dissociation is presented. In general, both final states tend to exhibit similar production properties.RiassuntoSi è fatto uno studio comparativo degli stati finali pπ+π+π−π0 e nπ+π+π+π− che risultano dalle interazioni π+p ad un impulso del fascio incidente di 10.3 GeV. Si vede una notevole produzione di risonanze in entrambi gli stati finali e si presenta una prova della produzione attraverso la dissociazione di diffrazione doppia. In generale, entrambi gli stati finali tendono a mostrare proprietà di produzione simili.РеэюмеПроводится сравнительное исследование конечных состояний рπ+π+π−π0 и nπ+π+π+π−, обраэуюшихся в π+р вэаимодействиях при импульсе падаюшего пучка 10.3 ГзВ/с. Наблюдается интенсивное рождение реэонансов в обоих конечных состояниях. Приводится подтверждение для случая рождения череэ двойную дифракционную диссоциацию. В обшем случае оба конечных состояния проявляют аналогичные свойства по отнощению к рождению.