Ericson fluctuations in the $\pi^{\pm}p$ systems in the energy range 2 to 3.5 GeV

Existing data on pi /sup +or-/p total cross-sections and 180 degrees elastic differential cross-sections in the energy range 2<E/sub cm /<3.5 GeV are used to estimate the fluctuating differential cross- section within the statistical models of Ericson and Frautschi. A mass spectrum of the form rho (m)=a(m/m/sub 0/)/sup b/exp(cm) describes correctly the fluctuations observed in total cross-sections and in 180 degrees elastic differential cross-sections. The mass spectrum is found to be denser for pi /sup -/p than for pi /sup +/p. (23 refs).