  The ratio R_K=Gamma(Ke2)/Gamma(Kmu2) provides a very powerful probe for the
weak interactions structure. This ratio of decay rates is calculated with very
high precision within the Standard Model but the corrections due to the
presence of New Physics could be as high as 3%. The data obtained by the NA48
experiment at the CERN SPS accelerator during a 56 hours special run in 2004
has been analyzed.The precision of the preliminary result for R_K is two times
better than the world average but is still insufficient to probe the existence
of physics Beyond the Standard Model. Currently the experiment is taking data
dedicated to the sub-percent precision measurement of R_K.
