1. e-pair Search in CSD Tsutomu Fukuda Nagoya-univ.

2. Why using e-pair? e-pair is from nu-int. → Brick finding By using e-pair ( request parallelism between 2trks), we can reject a few too many BG. In other words, we can pick up trks at high efficiency. For example, we can use 3/4CSD Trk or BaseTrk, of course 4hold Trk. For Direct VTX hunting in down stream event.

3. Search e-pair in CSD Trk This time, I use ¾ CSD Trk. Scanning Area is 121mm x 95mm. Data set is 23CSD/15event. < 500micron, < 40mrad → e-pair candidate Number of CSD Trk

4. Estimate BG pair made by random Noise # of CSD trks # of pairs ● is Estimated MC BG. － is Poisson distribution. < 500micron < 40mrad P n = m n /n! * e -m P 0 = e -m N pair = N CSDTrk *(1-P 0 ) = N CSDTrk *(1-e -m ) m=(500 micron ) 2 π/(121 mm * 95 mm ) * (0.04 rad ) 2 π/(1.3 rad ) 2 *N CSDTrk

5. Position difference vs Angle difference (BG) dr da

6. DATA vs BG DATAEstimated BG da dr

7. DATA vs BG DATAEstimated BG Manual check : compton trk make ghost. da dr

8. Where is e-pair ? CSD PL01 PL06 ~ 6.5mm (~1X 0 ) ~ 4.2mm dr da

9. Where is e-pair ? CSD PL01 PL06 ~ 4.2mm dr da ~ 6.5mm (~1X 0 )

10. 39030 ● DATA ● BG e-pair

11. 14850 ● DATA ● BG Comptons make ghost Film edge Xray mark Comptons make ghost

12. Summary For searching e-pair in CSD, I propose one of technique of analysis. I will develop this technique.

13. Other CSD

14. 16660 ● DATA ● BG

15. 16918 ● DATA ● BG

16. 16919 ● DATA ● BG

17. 16969 ● DATA ● BG

18. 17023 ● DATA ● BG

19. 20122 ● DATA ● BG

20. 31638 ● DATA ● BG

21. 33540 ● DATA ● BG

22. 34406 ● DATA ● BG

23. 34841 ● DATA ● BG

24. 38537 ● DATA ● BG

25. 39031 ● DATA ● BG

26. 41586 ● DATA ● BG

27. 41613 ● DATA ● BG

28. 50855 ● DATA ● BG

29. 51264 ● DATA ● BG

30. 53486 ● DATA ● BG

31. 54963 ● DATA ● BG