Results from the NA48 experiment on the semileptonic decays of charged kaons

In the 2003 and 2004 years the NA48/2 experiment collected a large sample of K± decays. Using a run with minimal trigger conditions a sample of 2.5 × 10 K± → πμνμ (K± μ3) events and 4.0 × 10 K± → πeνe (K± e3) were collected. These samples allow a precise measurement of the form factors according to various parameterisations. In this report the event selections and the fitting procedure are described and preliminary results are presented.