1. Sabino Meola Charged kaon group meeting 12 October 2005 Status of analysis

2. Sabino Meola Charged kaon group meeting 12 October 2005 The aim is to measure two relative branching ratios Two normalization samples: - to events in order to obtain a cancellation of the systematic errors. - to events in order to keep under control the track-to-cluster association efficiency.

3. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS K 00  3 The measurement strategy is articulated in 5 steps: 1.Neutral vertex (4  ).  →   association. 3.Kinematic fit. 4.Track to cluster association. 5.Background rejection.

4. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS K 00  3

5. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS K 00  3

6. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS K 00  3 Signal increase by a factor ~ 3.

7. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS K 00  3 Background to signal ratio ~ 1:1 (K 00 p 3 scaled by 23%)

8. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS Ke3 The measurement strategy is articulated in 3 steps: 1.Neutral vertex (2  ). 2.Track to cluster association. 3.Background rejection.

9. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS Ke3 We consider the E 2 miss -P 2 miss

10. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS Ke3 Background to signal ratio 6:1

11. Sabino Meola Charged kaon group meeting 12 October 2005 K 00 e4 VS Ke3 Evaluate the contribution e TCA on data using a sample of Ke3 events. Purity ~ 98%.

12. Sabino Meola Charged kaon group meeting 12 October 2005 Conclusions The measurement method allows to estimate the K 00  3 background contribution directly from data. Normalization to    3 events guarantees a cancellation of the systematic effects. The high purity sample of Ke3 events allows to evaluate on data the track-to-cluster association efficiency. Will benefit of 2 fb -1 statistics.