Study of the Ds+ → π-π+π+ decay and measurement of f0 masses and widths

From a sample of 848 +/- 44 D-s(+) --> pi (-) pi (+) pi (+) decays, we find Gamma (D-s(+) --> pi (-) pi (+) pi (+))/Gamma (D-s(+)--> phi pi (+)) = 0.245 +/- 0.028(-0.012)(+0.019). Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels rho (0)(770)pi (+), rho (0)(1450)pi (+,) f(0)(980)pi (+), f(2)(1270)pi (+), and f(0)(1370)pi (+). We also present the values obtained for masses and widths of the resonances f(0)(980) and f(0)(1370).