Investigation of rho-meson production in πp interactions at 3.9 GeV/c

We have investigated the ρ-meson production mechanism in the three reactions π^±p->ρ^±p and π⁻p->ρ⁰n at 3.9 GeV/c (s=8.2 GeV²) using the prism-plot technique. Differential cross sections at all momentum transfers are presented. A significant backward peak has been found in all three reactions. The differential cross sections for these backward peaks are given and are compared with the equivalent pion elastic and charge-exchange cross sections in the backward direction. Using a linear combination of the three differential cross sections we have isolated the I=0 exchange contribution in the forward direction. This differential cross section has a zero at -t=0.45 (GeV/c)² and is fitted by the dual absorptive model of Harari with an interaction radius of 1.2 F. The total I=0 cross section is calculated and compared with similarly determined cross sections at higher momenta. An analysis of the properties of the other possible spin-parity exchanges is also presented.