1. Neutrino Oscillation Physics at a Neutrino Factory Rob Edgecock RAL/CERN-AB

2. Outline Neutrino Factory accelerator “ “ detector Reminder of phenomenology Atmospheric parameters Sign of  m 2 23  13 and  Degeneracies Conclusions

3. Neutrino Factory Accelerator Important parameters: Muon energy= 20 or 50 GeV Intensity= 10 21 Muon energy= 20 or 50 GeV Intensity= 10 21 muon decays/year

4. Neutrino Factory Accelerator Advantages of a Neutrino Factory: Muon decay: Muon decay: Pure beam of equal numbers of  and e Pure beam of equal numbers of  and e Can look for: Can look for: First requires “simple” detector First requires “simple” detector High intensity (especially e ) High intensity (especially e ) Precisely known intensity and composition Precisely known intensity and composition Precisely known energy spectra Precisely known energy spectra

5. Neutrino Factory Detectors Magnetised iron calorimeter 20m long 10m radius 40kT Events in 1 year: 1.0x10 5 2.4x10 6 1.2x10 6 3500km 1.1x10 5 5.9x10 7 3.5x10 7 732km Signal sin 2  13 =0.0 1 Baseline

6. Neutrino Factory Detectors For e or  identification  Liquid argon TPC, etc e-id up to 5 GeV

7. Neutrino Factory Detectors LANNDD - 70kT - 61m x 44m - up to 1T - 18.5MA - coil: 71kT - yoke: 677kT

8. Phenomenology P(   e ) to lowest order in the matter effect: where To first order, ignoring matter effect and CP:

9. Phenomenology 20 GeV NF at 3500km

10. Physics Precise measurement of atmospheric parameters Precise measurement of atmospheric parameters Sign of  m 2 23 Sign of  m 2 23  13  13   Solar parameters Solar parameters e   e  

11. Physics From Bueno et al Nucl Phys B589 (2000) 577 Characterise as: - electrons - right-sign muons - wrong-sign muons - others Plots are for: E = 30 GeV L = 7400 km 10 20  decays 10 kT detector

12. Atmospheric Parameters Fitting to plots, after kinematic cuts No background Perfect resol n Background and resol n Resolutions achieved:1% in 10% in

13. Sign of  m 2 Only e have CC interactions with electrons in matter  effective mass Modifies transition probability:  where

14. Sign of  m 2 Integrated Energy bins 2x10 20 muon decays SMA parameters

15.  …….in case where one/both solar parameters small! Determined from a fit to energy spectra Determined from a fit to energy spectra This time, wrong sign muons dominate This time, wrong sign muons dominate No backgroundBackground 90% CL 732km 3500km 7332km

16.  Probably the most important parameter Probably the most important parameter The good news The good news

17.  The bad news…….matter effect……. The bad news…….matter effect…….

18.  …….and correlations…….. …….and correlations……..

19.  …….and degeneracies …….and degeneracies  13 =8 o,  =-90 o, 0 o, 90 o, 180 o

20. Degeneracies Degeneracy: 2 or more parameter sets fit the same data Three types, all of which can effect measurement of  &  13 : (1) (2) (3) They limit the accuracy of the parameter measurement (1) 

21. Degeneracies  13 large NB depends on L/E  possible solutions Two baselines and E-dependence at NF NF + SB combination Two off-axis detectors e   as well as e  

22.  13 =8 o,  =-90 o, 0 o, 90 o, 180 o Degeneracies NuFact at 2810km + SB at 130KM NuFact at 732km + SB at 130KM large small

23. Silver Channel Golden:Silver: 40kT magnetised iron at 3000km 4kT emulsion at 732km  Parameters:  = 90 o  = 5 o Lines of equivalent probability Solve ambiguities for all  and   1 o

24. Sensitivities Intermediate and long baseline best Resolution: ~0.1 o for  13 ~20 o for 

25. Comparisons 90% CL JHF-HK = 4MW, 1000kT; 6 years, 2 years NuFact-II = 5.3 x10 20 useful  /yr, 50kT; 4 years  

26. Comparisons

27. Conclusions Neutrino Factory is the ultimate long baseline facility Neutrino Factory is the ultimate long baseline facility In one year…… atmospheric parameters: sign of : 400  sin 2  13 : 4 x 10 -4 at 90% CL  : 90 o to <2 x 10 -5 In one year…… atmospheric parameters: sign of : 400  sin 2  13 : 4 x 10 -4 at 90% CL  : 90 o to <2 x 10 -5 The only serious competition from combinations of others The only serious competition from combinations of others Can also do a wide range of other physics: - short baseline, high intensity neutrino physics - high intensity slow muon physics - test bed for other projects: muon collider proton machines Can also do a wide range of other physics: - short baseline, high intensity neutrino physics - high intensity slow muon physics - test bed for other projects: muon collider proton machines 1% in 10% in