Charged kaon analysis Ratio o preliminary result Total

Charged kaon analysis Ratio o/ (preliminary result) Total statistics : 14 pb-1 ± + – 0 , 0. 3306 0. 0012 (stat) + (? )(sys. ) e ± 0 , 0 0 • World Data • 0. 3331 0. 0028 (fit), 0. 3316 0. 0032 (Average) (PDG) • 0. 339 0. 007 (CMD-2 preliminary, 2000) • 0. 3329 0. 0047 (USHER - 1992) • 0. 3355 0. 0057 (WEISSENBERG - 1976) • 0. 305 0. 018 (ZELLER - 1969) • 0. 3277 0. 0065 (AERBACH - 1967) K K 0 Cuts : -peak : 0. 225 Ge. V/c<Pcms<0. 245 Ge. V/c -peak : 0. 195 Ge. V/c<Pcms<0. 215 Gev/c Corrections for K

Charged kaon analysis BR o and (preliminary estimation) Total statistics : 4 pb-1 o • • • Exp. ratio = 0. 1916 0. 0006 MC ratio = 0. 1972 0. 0024 Exp. data corrected by MC = 0. 2056 0. 0026 (stat. ) + (? ) (sys. ) • • • Exp. ratio = 0. 5587 0. 0011 MC ratio = 0. 5788 0. 0047 Exp. data corrcted by MC = 0. 6130 0. 0050 (stat. ) + (? ) (sys. )

Main problem for charged kaons Kaon track splitting (15 %) : Correct Vertex • RED - momentum distribution of secondary particles from KINE bank, if presents vertex from DVFS, MC data • PINK - momentum distribution of secondary particles from DVFS bank, MC data

Main problem for charged kaons Secondary vertex selection (used for kaon BR as normalization factor): Momentum spectrum after corrections • Corrections : | Pkaon - Psecondary | < 40 Me. V • 0. 14 < | - | kaon - secondary| | < 3. 0

Main problem for charged kaons Other tasks : • Estimation of trigger efficiency • Background / track reconstruction dependency • Investigations of systmatic errors