0 nbb decay to the excited state 0 + of 130 Xe

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# 0 nbb decay to the excited state 0 + of 130 Xe - PowerPoint PPT Presentation

## 0 nbb decay to the excited state 0 + of 130 Xe

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1. 0nbb decay to the excited state 0+ of 130Xe Comparison of the GE and SC analyses S. Di Domizio, December 2010

2. Part 1: comparison of the methods In the following slides I will evaluate the efficiencies using the SC cuts with the GE and SC algorithms

3. Efficiency – scenario1 – SC – 536 e = (0.82 +/- 0.03)%

4. Efficiency – scenario1 – SC – 734 e = (0.82 +/- 0.02)%

5. Efficiency – scenario1 – SC – 1257 e = (0.80 +/- 0.03)%

6. Efficiency – scenario2 – SC - 1257 e = (2.58 +/- 0.04)%

7. Efficiency – scenario2 – SC – 1270 e = (2.56 +/- 0.03)%

8. Efficiency – scenario3 – SC – 536 e = (1.72 +/- 0.03)%

9. Efficiency – scenario3 – SC – 1991 e = (1.76 +/- 0.03)%

10. GE – scenario1 - 1257 Using GE algorithms and SC cuts

11. GE – scenario2 - 1270 Using GE algorithms and SC cuts

12. GE – scenario3 - 1257 Using GE algorithms and SC cuts

13. Part 2: comparison of the results In the following slides I will summarize the differences in the two approaches and will extract the half life limits

14. Comparison statistics GE SC N·t = 9.11 x 1025 y N·t = 8.74 x 1025 y values reported in the note N·t = 9.50 x 1025 y N·t = 8.96 x 1025 y Forgot to include the three “dead” channels 2, 3 and 50 “My” evaluation with “SC” method efficiency Geometric only total (with psa, noise, etc.)‏ GE SC GE SC scenario1 0.60% 0.80% scenario1 0.48% 0.64% scenario2 2.29% 2.58% scenario2 1.93% 2.18% scenario3 1.41% 1.75% scenario3 1.19% 1.48%

15. Result (GE)‏ G < 6.74 x 10-25 y-1 90%CL T1/2 > 1.03 x 1024 y 90%CL Posterior pdf for G

16. Result (SC)‏ G < 5.98 x 10-25 y-1 90%CL T1/2 > 1.16 x 1024 y 90%CL Posterior pdf for G

17. Part 3: the approach proposed by Frank In the following slides I will show the method and the results I obtained by treating the difference between GE and SC analysis as a systematic error

18. Treating the differences as syst errors Use the approach discussed in Adam's internal note scenario efficiency 1 (0.56+/-0.08)% Statistics: N·t = (9.23 +/- 0.27) x 1025 y 2 (2.06+/-0.13)% 3 (1.34+/-0.15)%

19. Result (combined)‏ G < 6.39 x 10-25 y-1 90%CL T1/2 > 1.09 x 1024 y 90%CL Posterior pdf for G

20. Summary GE: T1/2 > 1.0 x 1024 y @90%CL SC: T1/2 > 1.2 x 1024 y @90%CL GE+SC: T1/2 > 1.1 x 1024 y @90%CL

21. Method comparison Consider the limit case of an experiment with two crystals where one has 100% dead time and the other has 0 dead time. Since no coincidences can be recorded in these conditions, the number of signal and background counts will be zero. The SC approach would give a finite value for both the efficiency and the accumulated statistics, thus resulting in a non trivial limit for the half life of the process. The GE approach would give a finite value for the statistics and a null value for the efficiency, therefore nothing can be said about the half life of the process.

22. Treating the differences as syst errors