The reaction π−p → ηn up to pη1 = 450 MeV/c: experimental results and partial-wave analysis

An accurate measurement of $\text{d}\text{σ}\text{d}\text{Ω}\text{(π}{}^{\mathrm{?}}\text{p}\text{→ η}\text{n}\text{)}$ at 1531 MeV total energy (expanded) up to l = 4 Legendre polynomials) requires reconsideration of previous angular distribution fits which were expanded only up to l = 2 and of subsequent partial-wave analysis. An energy-dependent partial-wave analysis has been performed here for $\text{p}{}_{\mathrm{\eta }}{}^1$ up to 450 MeV/c. In addition to the well-known S₁₁ (1520 MeV) resonance, either the P₁₁ (1532 MeV) or the P₁₃ (1530 MeV) resonance is found to be strongly coupled to the η-n channel. In both cases, the P₁₁ (1729 MeV) resonance is needed as is the weakly coupled D₁₃ (1525 MeV) resonance. The decay states in the ηn channelare compared to the SU(3) and SU(6)_W predictions.