Resonant structure in the. pi. /sup +/. pi. /sup +/. pi. /sup -/. pi. /sup -/ system between 1. 5 and 1. 9 GeV

Resonant structure is studied in the 1.5-to-1.9-GeV mass region of the neutral four-pion system in the reaction ..pi../sup +/n..-->..p..pi../sup +/..pi../sup +/..pi../sup -/..pi../sup -/ at 6 GeV/c incident momentum. The rho/sup 0/ and A/sup + -//sub 2/ content are determined as a function of the four-pion mass. The 4..pi.. mass spectrum is best fitted by two resonances, both of which decay predominantly into rho/sup 0/..pi../sup +/..pi../sup -/, each with evidence for an appreciable A/sub 2/..pi.. component.