Study of the identity effects of pions produced in. pi. /sup -/p interactions at p = 40 GeV/c

The effective-mass spectra of two-pion and three-pion systems produced in ..pi../sup -/p interactions at p = 40 GeV/c are analyzed. Interference effects are observed for ..pi../sup + -/..pi../sup + -/ systems at an effective mass M< or approx. =0.4 GeV. The effect is more pronounced for ..pi../sup -/..pi../sup -/ systems than for ..pi../sup +/..pi../sup +/, which can be due to the different mechanisms of production of ..pi../sup +/ and ..pi../sup -/ mesons. Interference of three identical pions, which cannot be explained by only two-particle correlations, is observed. For systems of nonidentical pions no such correlations are observed.