Relatore
Venelin Kozhuharov
(Univerity of Sofia "St. Kl. Ohridski")
Descrizione
The ratio $R_K = \Gamma(K^{\pm}\to e^{\pm}\nu) /
\Gamma(K^{\pm}\to \mu^{\pm}\nu) $ 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
corrections due to the presence of New Physics could be as high
as 3\%. The data obtained by the NA48 experiment in two years of
data taking at the CERN SPS accelerator has been analyzed. The
obtained result for $R_K$ is two times more precise than the
world average but is still insufficient to probe the existence of
physics Beyond the
Standard Model. A new run in 2007, aimed for a sub-percent
precision measurement of $R_K$, has been proposed and approved.
