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If q 13 is large, then what ?

If q 13 is large, then what ?. Hisakazu Minakata Tokyo Metropolitan University . Title too timely? Yes, but meant to be a speculative one when proposed. Apparently q 13 is large. 6 events at T2K ! . Released in June 15@KEK. T2K appearance event distribution. MINOS also saw excess.

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If q 13 is large, then what ?

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  1. If q13 is large, then what ? Hisakazu Minakata Tokyo Metropolitan University

  2. Title too timely? Yes, but meant to be a speculative one when proposed Nufact2011@CERN-UNIGE

  3. Apparently q13 is large 6 events at T2K ! Released in June 15@KEK Nufact2011@CERN-UNIGE

  4. T2K appearance event distribution Nufact2011@CERN-UNIGE

  5. MINOS also saw excess Nufact2011@CERN-UNIGE

  6. Global analysis Fogli et al. June 29 • All n experiments coherently support q13 ~ 8 degree Nufact2011@CERN-UNIGE

  7. We will soon hear more about this from reactors! Nufact2011@CERN-UNIGE

  8. There are two issues (at least) Nufact2011@CERN-UNIGE

  9. Two issues of large q13 • What is the influence of large q13 on strategies of future n oscillation experiments ? • What the large q13 means? Physics behind the large q13 Smirnov’s talk Mohapatra’s talk … Nufact2011@CERN-UNIGE

  10. Wide possibilities are now open for CP • Conventional nmsuperbeam can do a much better job for CP (and possibly for mass hierarchy) than it was thought • This means that we should reconsider about strategy for CP • I believe megaton-scale water Cherenkov / 100 kt liquid Ar is still needed for robust discovery of CPV • Yet, the paths to go there could have more variety “guerrilla type” approaches possible Nufact2011@CERN-UNIGE

  11. Various options become possible for CP Nufact2011@CERN-UNIGE

  12. Reactor accelerator combination HM-Sugiyama 04 Huber et al. 09 Nufact2011@CERN-UNIGE

  13. n + n-bar combination in NOnA / T2K NOVA@wine&cheese June17 Nufact2011@CERN-UNIGE

  14. Reactor-accelerator & n+n-bar methods • Apparently the methods works, but unlikely to cover all the d space • Quantitative estimation of CP sensitivity required very interesting !! • Results of CP sensitivity studies indicate the importance of mass hierarchy resolution Nufact2011@CERN-UNIGE

  15. Various options possible… MEMPHYS: Dashed line = combining SPL + beta Campagne et al. 07 Nufact2011@CERN-UNIGE

  16. What do you propose? Nufact2011@CERN-UNIGE

  17. Opening the possibility of “all in one” • With large q13 ~ Chooz limit a megaton scale water Cherenkov can do many • With intense n and n-bar beam it can measure d • With gigantic atmospheric n events it could determine mass hierarchy • in situ measurement of everything in a single detector • It can do proton decay • It can do many astrophysics too Kakuno-san’s talk water Cherenkov vs. liquid Ar vs. TASD debatable Nufact2011@CERN-UNIGE

  18. Issues in precision measurement of CP Nufact2011@CERN-UNIGE

  19. megaton class detectors (examples) T2K II MEMPHYS Nufact2011@CERN-UNIGE

  20. CP sensitivity is not maximal at sin2q13=0.1 MEMPHYS Nufact2011@CERN-UNIGE

  21. T2KK vs. T2K II Comparison hep-ph/0504026 Total mass of the detectors = 0.54 Mton fid. mass 4 years neutrino beam + 4 years anti-neutrino beam 4MW! T2KK Mass hierarchy CP violation (sind≠0) T2K 3 s (thick) 2 s (thin) Nufact2011@CERN-UNIGE

  22. Precision CP requires … • T2K-T2KK comparison seems to indicate necessity of mass hierarchy resolution • importance of lifting sign Dm2 degeneracy • Comparison of different error treatments in nn-bar shows the relative cross section error affects CP sensitivity Supported by analysis in Kakuno-san’s talk n cross section measurement crucially important Nufact2011@CERN-UNIGE

  23. Does large q13 require new oscillation formula? Nufact2011@CERN-UNIGE

  24. Large q13 corrections to Cervera et al. formula Good perturbative formula for small q13 with s13 ~ Dm221 / Dm231 = e : 2nd order formula Cervera et al. 00 But, for large q13 ~10 deg. s13 ~\sqrt{e } higher order corrections needed PNC ~ s134, or ~ s132 e Computed: K. Asano-H.M. JHEPJune7, 2011 Nufact2011@CERN-UNIGE

  25. Some features of the new formula rD=Dm221/Dm231rA=a/Dm231D=Dm231 / 2E All the d dependence is in half-integer power of e General theorems! Nufact2011@CERN-UNIGE

  26. Correction terms are small All the correction terms are of order ~e2 General theorems! rD=Dm221/Dm231rA=a/Dm231D=Dm231 / 2E Nufact2011@CERN-UNIGE

  27. Is parameter degeneracy affected by large q13? Nufact2011@CERN-UNIGE

  28. P degeneracy well understood Cervera et al. formula HM-Uchinami JHEP10 Nufact2011@CERN-UNIGE

  29. Is P degeneracy unchanged for large q13? Cervera et al. formula • One can show on general ground that PNC must be order (Dm221 / Dm231)2 ~ 0.001 • Difference between Cervera sol. and our solutions is tiny (apart from a particular region) PNC ~ s134, or ~s132 Dm221 / Dm231 Nufact2011@CERN-UNIGE Asano-HM JHEP11

  30. What large q13 means? Nufact2011@CERN-UNIGE

  31. What large q13 means? • Large q13 is natural because in U=Vl+Vn two angles are large, and hence extremely small q13 is not expected, • Anarchy ? • The above argument assumes no symmetry is hidden symmetries which enforce q13 =0 somewhat discouraged (?) unless you have good reasons Nufact2011@CERN-UNIGE

  32. Large q13 in QLC context QLC based on observation: q12 + qC = p/4 Raidal 04, HM-A.Smirnov 04 Bimaximal mixing from neutrinos Bimaximal mixing from charged leptons Large q13 prefers bimaximal mixing from n Nufact2011@CERN-UNIGE

  33. Conclusion • large q13 opens up wide range of possibilities for hunting CP & mass hierarchy • While guerrilla type approach is possible, a charming case would be to determine all at once by a megaton-scale detector (+proton decay) Hyper-K • Yet, precision measurement would require resolution of sign-Dm2 degeneracy • Physical meaning of the large q13 has to be understood Nufact2011@CERN-UNIGE

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