Study of the reaction pi(-)p up arrow ->pi(-)pi(+)n on a polarized proton target at 1.78 GeV/c. Experiment and amplitude analysis

We present the results of an experimental study of the reaction of dipion p roduction by a beam of negative pions with momentum 1.78 GeV/c on polarized proton and liquid hydrogen targets. The experiment covers the region of di pion masses near the mass of the rho-meson and small transferred momenta \t \ < 0.2 (GeV/c)(2). The complete set of spin density matrix elements was re constructed and model-independent and model-dependent amplitude analyses of the reaction were performed. The experiment allows us to exclude the ambig uity of the amplitude analysis existing at high energies. The results conta in evidence in favour of the existence of a sigma(750) 00(++). The data als o allows us to estimate the intercept of the a(1)-meson Regge trajectory. T he experiment was performed at the ITEP proton synchrotron, Moscow. (C) 199 9 Elsevier Science B.V.