Resonance production in π+d reactions at 5.4 GeV/c

Abstract

The reactions π+n → pπ+π−, π+n → pπ+π−πo and π+n → pK+K− have been studied at 5.4 GeV/c. Cross sections (normalized to the reaction π−p → nπ+π−) are estimated as 1.60 ± 0.25 mb, 1.43 ± 0.24 mb and 0.14 ± 0.03 mb, respectively. Resonance parameters, production cross sections, and density-matrix elements are presented for the ϱo and fo produced in the pπ+π− final state; cross sections are given for ϱ, Δ(1236), ωo, ηo and A2o resonances produced in the pπ+π−πo final state. Density-matrix elements are presented for the ωo and the variation of these elements as a function of beam momentum is discussed. Evidence is presented for a low-mass enhancement in the pπ−πo system produced diffractively in the reaction π+n → (pππ)oπ+. We see no indication of φo(1020) or S∗ (1070) production in the K+K− system.