Measurement of the decay UPSILON(2S). --> pi pi. UPSILON(1S)

We have investigated the hadronic transitions UPSILON(2S) ..-->.. ..pi../sup 0/..pi../sup 0/UPSILON(1S) ..-->.. ..gamma gamma gamma gamma..l +l/sup -/ (l = ..mu.. or e) and UPSILON(2S) ..-->.. ..pi../sup +/..pi../sup -/UPSILON(1S) ..-->.. ..pi../sup +/..pi.. /sup -/e/sup +/e/sup -/ using the Crystal Ball detector at the DESY e/sup +/e/sup -/ storage ring DORIS II. Using the present world-average value of B/sub l/l(UPSILON(1S)) = 2.9 +- 0.3)% we derive branching ratios B(UPSILON(2S) ..-->.. ..pi../sup 0/..pi../sup 0/UPSILON(1S)) = (8.0 +- 1.5)% and B(UPSILON(2S) ..-->.. ..pi../sup +/..pi../sup -/UPSILON(1S)) = (16.9 +- 4.0)%. We also present results on the invariant-mass spectra and the angular distributions of the dipion system.