The K^-^+ S-wave from the D^+ K^-^+^+ decay
Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K -pi + S-wave amplitude from the decay D + to K -pi +pi +. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K -pi + system.