1. Measuring Atmospheric Parameters with SuperBeams Enrique Fernández Martínez Departamento de Física Teórica and IFT Universidad Autónoma de Madrid

2. Outline Introduction Oscillation parameters Experiments description Subleading effects in disappearance m 2 atm and the sign degeneracy 23 and the octant degeneracy The effects of 13 and T2K-1 bounds revised Conclusions

3. The oscillation parameters What we already know Solar sector Atm sector What we still dont know sin2 13 < 0.40 cp Mass hierarchy Octant of 23 M. C. González García hep-ph/0410030 23 = 35º–55º 12 = 28º–38º

4. Fluxes T2K-1SPL flux from decay at flux from decay L=130Km Old SPL fluxes courtesy of Gilardoni New fluxes Campagne et al. hep-ex/0411062 L=295Km T2K fluxes courtesy of J.J. Gómez Cadenas OA2º

5. Event Rates T2K-1 B1B2B3B4 No osc. N 75322282273757 Signal N 46101381239 SPL - + No osc. N 2424525467 Signal N 17461614 L=130Km 5yr exposure with a 22.5Kt water cerenkov detector for T2K-1 2yr + 8yr exposure with a 440Kt water cerenkov detector for the SPL L=295Km Statistics dominatedSystematics dominated 4 energy bins of 200MeV Between 0.4 – 1.2GeV

6. The importance of energy resolution 13 = 0º = 0º T2K-1SPL 90% CL contours 5% systematic error and backgrounds taken into account

7. The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE27.0

8. The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV

9. The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV

10. The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV E3 = 0.8 - 1.0GeV

11. The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV E3 = 0.8 - 1.0GeV E4 = 1.0 - 1.2GeV

12. The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV E3 = 0.8 - 1.0GeV E4 = 1.0 - 1.2GeV

13. The disappearance channel Where 231213 2sin2 2 cos ~ J sin 2 13 < 0.4 05.0 2 L sol E m 2 2 12 E. K. Akhmedov et al. hep-ph/0402175 A. Donini et al. hep-ph/0411402 E m atm 2 2 23

14. The sign degeneracy Input: 13 = 0º = 0º L L sol atm + O 2 2 sin 2 2sin1 2 23 2 L sol + O 2

15. The sign degeneracy L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 Input: 13 = 0º = 0º

16. The sign degeneracy Fit assuming inverted hierarchy Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2

17. The octant degeneracy Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2

18. The octant degeneracy Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2

19. The effect of 13 Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2

20. The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

21. The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

22. The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

23. The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º, 6º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

24. The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º, 6º, 8º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

25. The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º, 6º, 8º, 10º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

26. The effect of Input: 13 = 8º = 0º Assuming = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

27. The effect of Input: 13 = 8º = 0º Assuming = 0º, 90º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

28. The effect of Input: 13 = 8º = 0º Assuming = 0º, 90º, 180º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23

29. T2K-1 errors revised m 2 = (2.43 – 2.60)·10 -3 eV 2 sin 2 2 > 0.97 tan 2 = 0.73 – 1.39 m 2 = (2.50 ± 0.06)·10 -3 eV 2 sin 2 2 > 0.98 Y. Itow et al. hep-ex/0106019 m 2 = (2.45 – 2.56)·10 -3 eV 2 sin 2 2 > 0.98 tan 2 = 0.76 – 1.31 Present: m 2 = (1.7 – 3.5)·10 -3 eV 2 sin 2 2 > 0.9 tan 2 = 0.53 – 2.04 m 2 = (-2.63 – -2.49)·10 -3 eV 2 Input: 13 = 0º 23 = 45º = 0º 90% CL

30. T2K-1 errors revised m 2 = (2.42 – 2.61)·10 -3 eV 2 sin 2 2 = 0.94 – 0.99 tan 2 = 0.62 – 0.85, 1.21 – 1.66 m 2 = (2.44 – 2.58)·10 -3 eV 2 sin 2 2 = 0.95 – 0.99 tan 2 = 0.63 – 0.81, 1.24 – 1.58 Present: m 2 = (1.7 – 3.5)·10 -3 eV 2 sin 2 2 > 0.9 tan 2 = 0.53 – 2.04 m 2 = (-2.64 – -2.47)·10 -3 eV 2 90% CL Input: 13 = 0º 23 = 40º = 0º

31. Conclusions The measurement of 13 and will rely heavily on an improvement of the measure of 23 and m 2 23 Precision measurements of 23 and m 2 23 need energy resolution and events above and below the oscillation peak The errors on the 23 and m 2 23 are somewhat larger due to the dependence of the disappearance signal on 13, and the mass hierarchy This dependence can be exploited combined with the appearance channel to solve degeneracies

32. T2K-2 T2K-1 5% systematic error

33. T2K-2 T2K-1 2% systematic error

34. No background and no systematic Systematic 0% No Background Systematic 5% With Background Errors dominated by statistics

35. 10% systematic Systematic 10%Systematic 5% Errors dominated by statistics

36. Energy Resolution Red histogram for true QE events Figure taken from Y. Itow et al. hep-ex/0106019

37. Double energy resolution 4 bins of 200MeV 8 bins of 100MeV

38. Double energy resolution 4 bins of 200MeV 8 bins of 100MeV