Investigation ofρ-meson production inπpinteractions at 3.9 GeV /c

Abstract

We have investigated the $\rho$-meson production mechanism in the three reactions ${\pi }^{\pm }p\to {\rho }^{\pm }p$ and ${\pi }^{-}p\to {\rho }^{0}n$ at 3.9 GeV/c ($s=8.2\mathrm{}$ ${\mathrm{GeV}}^2$) 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 $I=0\mathrm{}$ exchange contribution in the forward direction. This differential cross section has a zero at $-t=0.45\mathrm{}$ ${\mathrm{}(\mathrm{G}\mathrm{e}\mathrm{V}/\mathrm{c})\mathrm{}}^2$ and is fitted by the dual absorptive model of Harari with an interaction radius of ∼ 1.2 F. The total $I=0\mathrm{}$ 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.