Model-independent analysis of π−n → pπ−π−π0 and π−n → ρ−π−p final states at 5 and 9 GeV/c

Abstract

The final state π−n → pπ−π−π0 is investigated by means of the LPS technique. Cross-sections, mass spectra and four-momentum transfer distributions in each sector are reported. The sector corresponding to the π−n → (pπ−)(π−π0) grouping is the most aboundantly populated and it is dominated by ρ− production. A model-independent analysis of the three-body final state π−n → ρ−π−p allows us to evaluate the natural- and unnatural-parity exchange contributions as a function of the fourmomentum transfer to the ρ− and of the (pπ−) mass.