V. Picciarelli

A ϱ−π− enhancement at 1.32 GeV observed in 5 GeV/c π−d interactions

Abstract In the reaction π−d → p p π−π−πo at 5.04 GeV′c, a ϱ−π− enhancement at 1.32 GeV is observed. Its statistical significance is about 4 standard deviations. The production cross-section (15 μ b) excludes its identification with the (ϱoπ±) A2 resonance.

ϱπ resonances in π+π−πo system

Abstract Results on the analysis of neutral ϱπ system from π + d interactions at 5.1 GeV/ c are presented. Evidence for a new isoscalar resonance (ϱπ) is reported. Its mass, width and cross section are M = 1.636 GeV, Γ = 0.112 GeV and σ = 53 μ b, respectively. There is no evidence for H and A 1 o resonance production.

Ao2 production in π+d interaction

Abstract In ( π + π − π 0 ) invariant mass from the reaction π + d→p s p π + π − π o at 5.1 GeV/ c in the 81 cm Saclay D.B.C. exposed at CERN PS, we observed a peak at 1.32 ± 0.01 GeV with Γ = 0.12 ± 0.02 GeV. This peak has a ϱπ structure and corresponds to a T = 1, J P = 2 + resonant state.

Nππ enhancements observed in the reaction π−n → pπ−π−πo at 5 GeV/c

Abstract In the search for nucleon resonance production in the reaction π−d → (ps)pπ−π−πo at 5 GeV/c, the (pπ−πo) and (pπ−π−) spectra are investigated. Signals are observed in the 1.7 GeV region; however their characteristics do not fully agree with what is known on nucleon resonance structures from phase shift analysis. While these discrepancies are not as significative as that reported in the preceding letter; they also point toward difficulties in correlating resonant structures in production reactions to those observed in formation processes.

A 3 + production in π+d interactions at 5.1 GeV/c

ConclusionsThe present experiment confirms the production of the A3 resonance. The mass valueM = (1.673±0.040) GeV is in fairly good agreement with that found at different energies, but the width Г = (0.24±0.05) GeV is larger.The analysis shows a dominant fπ decay mode.The slope of the differential cross-section is similar to that found at higher energy, while the total cross-section is higher in comparison with that found at different incident energies.