1. Sergio Palomares-Ruiz June 22, 2005 Super-NO A Based on O. Mena, SPR and S. Pascoli hep-ph/0504015 a long-baseline neutrino experiment with two off-axis detectors

2. June 22, 2005 Sergio Palomares-Ruiz What we know and what we do not know about neutrinos We don’t know if there are sterile neutrinos We don’t know if there are sterile neutrinos We don’t know what the absolute mass of neutrinos is We don’t know what the absolute mass of neutrinos is We don’t know what is their nature: Majorana or Dirac We don’t know what is their nature: Majorana or Dirac We don’t know what is the mass mechanism We don’t know what is the mass mechanism We know that neutrinos do oscillate: have mass We know that neutrinos do oscillate: have mass We know that there are only 3 light active neutrinos We know that there are only 3 light active neutrinos

3. June 22, 2005 Sergio Palomares-Ruiz Solar sector  m 2 21 = (7.6 - 8.6) 10 -5 eV 2 sin 2  12 = (0.28 – 0.33) Reactor sector sin 2  13 < 0.041 Atmospheric sector |  m 2 31 | = (1.5 – 3.4) 10 -3 eV 2 sin 2 2  23 > 0.92 We don’t know the octant of  23 We don’t know the octant of  23 We don’t know whether there is CP violation in the lepton sector We don’t know whether there is CP violation in the lepton sector We don’t know the type of mass hierarchy We don’t know the type of mass hierarchy We don’t know whether  13 is different from 0 We don’t know whether  13 is different from 0 We know We know O. Mena and S. J. Parke, Phys. Rev. D69:117301, 2004

4. June 22, 2005 Sergio Palomares-Ruiz Degeneracies (  23,  /2 -  23 ) (  23,  /2 -  23 ) ( ,  13 ) ( ,  13 ) sign(  m 2 31 ) sign(  m 2 31 ) % % H. Minakata and H. Nunokawa, JHEP 0110:001,2001 ~ sin  ~ cos 

5. June 22, 2005 Sergio Palomares-Ruiz Resolving degeneracies : (  23,  /2 -  23 ) Atmospheric neutrino experiments Atmospheric neutrino experiments Sub-GeV events (solar term) Sub-GeV events (solar term) Multi-GeV events (matter effect) Multi-GeV events (matter effect) Very long-baseline neutrino experiments Very long-baseline neutrino experiments Through the solar term contribution Through the solar term contribution Neutrino factories and  beams Neutrino factories and  beams e →  and e →  e →  and e → 

6. June 22, 2005 Sergio Palomares-Ruiz Resolving degeneracies: ( ,  13 ) Long-baseline neutrino experiments Long-baseline neutrino experiments Reduce degeneracy under special configurations Reduce degeneracy under special configurations Reactor neutrino experiments Reactor neutrino experiments Only sensitive to  13 Only sensitive to  13 Atmospheric neutrino experiments Atmospheric neutrino experiments Neutrino factories and  beams Neutrino factories and  beams

7. June 22, 2005 Sergio Palomares-Ruiz Resolving degeneracies: sign(  m 2 31 ) Atmospheric neutrino experiments Atmospheric neutrino experiments Multi-GeV events Multi-GeV events Long-baseline neutrino experiments Long-baseline neutrino experiments Off-axis experiments Off-axis experiments Neutrino Factories and  beams Neutrino Factories and  beams Need of matter effects →  13  0

8. June 22, 2005 Sergio Palomares-Ruiz Off-axis concept D. Beavis et al., BNL Proposal E-889 Neutrinos produced in two body decays:  →  + 

9. June 22, 2005 Sergio Palomares-Ruiz Experimental set-up NO A Medium energy beam Medium energy beam 50 (30) kton calorimeter 50 (30) kton calorimeter L = 810 km L = 810 km Off-axis distance = 10 km Off-axis distance = 10 km → E = 2.3 GeV → E = 2.3 GeV 3.7 (6.5) x 10 20 pot/yr 3.7 (6.5) x 10 20 pot/yr Proton Driver = Proton Driver = 18.5 (25) x 10 20 pot/yr 18.5 (25) x 10 20 pot/yr Super-NO A NO A + another off-axis detector with the same L/E (L = 200 km) NO A + another off-axis detector with the same L/E (L = 200 km) We will consider 50 kton Liquid Argon detectors (high efficiency) We will consider 50 kton Liquid Argon detectors (high efficiency) Only neutrinos Only neutrinos 5 years 5 years No A 2nd detector = Super-No A D. S. Ayres et al. [NO A Collaboration], hep-ph/0503053

10. June 22, 2005 Sergio Palomares-Ruiz Probabilities Up to second order in  13,  12 /  13,  12 /A and  12 L Up to second order in  13,  12 /  13,  12 /A and  12 L A. Cervera et al., Nucl. Phys. B579:17, 2000 P(  → e ) = x 2 f 2 + 2 x y f g cos(  -  ) + y 2 g 2 x ≡ sin  23 sin 2  13 y ≡ (  m 2 21 /  m 2 31 ) cos  23 sin 2  12 f ≡  sin(  -AL/2)/(  - AL/2) g ≡ sin(AL/(2  ))/(AL/(2  ))  ≡  m 2 31 L / (4 E )

11. June 22, 2005 Sergio Palomares-Ruiz Asymmetry O. Mena, SPR and S. Pascoli, hep-ph/0504015

12. June 22, 2005 Sergio Palomares-Ruiz O. Mena, SPR and S. Pascoli, hep-ph/0504015

13. June 22, 2005 Sergio Palomares-Ruiz Bi-event plot for NO A O. Mena, SPR and S. Pascoli, hep-ph/0504015 P = A cos  cos  + B sin  sin  + C It collapses to a line if: (AB - AB) cos  sin  B = A B = -A cos  sin  NO A NO A 0.9 <  <  1.3

14. June 22, 2005 Sergio Palomares-Ruiz Bi-event plots for Super-NO A O. Mena, SPR and S. Pascoli, hep-ph/0504015 P F = A F cos  cos  + B F sin  sin  + C F P N = A N cos  cos  + B N sin  sin  + C N B F = A F B N = A N It collapses to a line if: (A F B  – A  B F ) cos  sin  It is always a line

15. June 22, 2005 Sergio Palomares-Ruiz Measurable integrated asymmetry O. Mena, SPR and S. Pascoli, hep-ph/0504015 PD 95% C.L.  2 analysis 99% 95% 90%

16. June 22, 2005 Sergio Palomares-Ruiz Comparison with NO A and T2K pot/yr = 6.5 x 10 20 pot/yr (PD) = 25 x 10 20 12 km off-axis 3 yrs + 3 yrs 6 yrs + 6 yrs with NO A + 3 yrs + 3 yrs with 2nd detector at second maximum With Super-No A only 5 yrs to get there D. S. Ayres et al. [NO A Collaboration], hep-ph/0503053

17. June 22, 2005 Sergio Palomares-Ruiz Conclusions Resolving degeneracies is a crucial task Resolving degeneracies is a crucial task Super-NO A: 2 off-axis (LAr) detectors with same L/E using the NuMI beam → determination of sign(  m 2 31 ) free of degeneracies Super-NO A: 2 off-axis (LAr) detectors with same L/E using the NuMI beam → determination of sign(  m 2 31 ) free of degeneracies Only need of 5 years of neutrino run to resolve the type of hierarchy down to sin 2 2  13 = 0.02 with Proton Driver (for all values of  ) Only need of 5 years of neutrino run to resolve the type of hierarchy down to sin 2 2  13 = 0.02 with Proton Driver (for all values of  ) Better capabilities than NO A + T2K at HK for determining the type of mass hierarchy Better capabilities than NO A + T2K at HK for determining the type of mass hierarchy