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Complementarity of Terrestrial Neutrino Experiments in Searching for  13

Complementarity of Terrestrial Neutrino Experiments in Searching for  13. Pasquale Migliozzi INFN - Napoli. P.M., F. Terranova Phys. Lett. B 563 (2003) 73 M. Komatsu, P.M., F. Terranova J. Phys. G. 29 (2003) 443. Outline. Definition of “on-peak” and “off-peak” experiment

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Complementarity of Terrestrial Neutrino Experiments in Searching for  13

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  1. Complementarity of TerrestrialNeutrinoExperiments in Searching for13 Pasquale Migliozzi INFN - Napoli P.M., F. Terranova Phys. Lett. B 563 (2003) 73 M. Komatsu, P.M., F. Terranova J. Phys. G. 29 (2003) 443

  2. Outline • Definition of “on-peak” and “off-peak” experiment • Two familiesscheme • Three familiesscheme • Possible scenarios after first results of the planned experiments and implications • q13 is so small the all give null result • q13 is larger than 7° • 4° < q13 < 7° • Conclusion Pasquale Migliozzi - INFN Napoli

  3. Two families scheme Maximum oscillation rate at Dm2L/4E=p/2  on peak In principle very easy, in practice very difficult! Pasquale Migliozzi - INFN Napoli

  4. 90% allowed regions for different exps as a function of the time 1990 1994 1997 Atmospheric exps Frejus Kamiokande IMB Super-K Macro Dm2 (10-3eV2) 2003 1998 1999 2000 2001 YEAR Dm2 versus YEAR NB Posc goes like (Dm2)2 From ’94 to ’03 it decreased by a factor 100!! Very difficult the tuning at the atmospheric mass scale! Impact both on nmnt and nm ne oscillation searches Pasquale Migliozzi - INFN Napoli

  5. Phase I exps Comparing different scenariosin a two families scheme Limits at 90% C.L. on sin22q13 and q13 (Dm223=2.5x10-3 eV2; sin2q23=1) LI = nominal CNGS; HI = nominal CNGS x 1.5 NB The CNGS sensitivity is limited by statistics  very important high intensity proton beam Pasquale Migliozzi - INFN Napoli

  6. Comment • Historically different projects have been compared by looking at the sensitivity computed assuming the two families scheme. However, this approximation is to simple: neutrino are at least three and are connected among them. • Interplay between q13 and the CP phase • The sensitivity depends on solar parameters Pasquale Migliozzi - INFN Napoli

  7. O1 leading term O2: 1 at osc. max O3: 0 at osc. max O4: suppressed by a2 The oscillation probability in the full PMNS scenario The hierarchy among the different O terms depends on the “on peak”-”off peak” choice Pasquale Migliozzi - INFN Napoli

  8. O1 O2 O3         O4             Different dependence on sign(Dm223)  Possible sinergy between JHF and NuMI-OA

  9. O1       O3             O2            O3            • Different hierarchy of O terms • Possible synergies between “on” and “off” –axis exps.

  10. All Phase I exps give null result Can we start the construction of future facilities (Super-Beams, Neutrino Factories) on firm bases? Can we safely exclude large values of q13 such that CP is not visible at future facilities (i.e. stop future programs)? The answer is no!

  11. Some considerations • To have an unambiguous answer the exps should • Perform a pure measurement of q13 (e.g. reactors) • Be able to disentangle q13-d intrinsic correlations which could result into an apparent suppression of q13 (e.g. neutrino + anti-neutrino run) • Have maximal q13 sensitivity for maximal CP violation • The only thing we can do with the proposed experiments is to OPTIMIZE THE DATA TAKING! Pasquale Migliozzi - INFN Napoli

  12. OPERA alone 5y HI beam Limits on a taken from a global fit to all available data: atmospheric+solar+reactor* /OPERA alone *M. Maltoni et al. hep-ph/0309130 3s allowed Three families analysis:sin22q13 as a function of solar and atmospheric Dm2 a = Dm2sol/|Dm2atmo| This plot has been obtained in the worst case: the larger value of q13 (varying dCP) is taken Pasquale Migliozzi - INFN Napoli

  13. Accelerator expts. sensitivity vs dCP There are dip values for which the sensitivity on q13 is even better than the one compute in the 2-flavour approximation (dCP=0). • Notice the different • behaviour on Dm2 of the • CNGS sensitivity • Possible measurement • of the sign of Dm231? Pasquale Migliozzi - INFN Napoli

  14. Dm2>0 Dm2<0 What happens if an exp decides to start with anti-neutrinos? At the present NuMI-OA is supposed to start data-taking with n BAD CHOICE: results similar to JHF, no synergies GOOD CHOICE: would be data-taking with anti-n, synergies! Pasquale Migliozzi - INFN Napoli

  15. q13 issue • The measurement of q13 is made complicated by the fact that oscillation probability is affected by matter effects and possible CP violation • Because of this, there is not a unique mathematical relationship between oscillation probability and q13 • Especially for low values of q13, sensitivity of an experiment to seeing nmnedepends very much on d • Several experiments with different conditions and with both n and anti-n will be necessary to disentangle these effects Pasquale Migliozzi - INFN Napoli

  16. q13 is larger than 7° Signal already visible at MINOS/ICARUS/OPERA

  17. CNGS at the start-up of JHF-SK • 3 years data taking at the CNGS • Sensitivity: sin22q13 < 0.035 @ 90%C.L. (a factor 4 better than CHOOZ) • Indication (90%C.L) of ne appearance if q13 > 7° 90% C.L. allowed region Pasquale Migliozzi - INFN Napoli Dm2<0 Dm2>0

  18. q13=5° q13=10° Allowed regions for JHF (5 years) + CNGS (8years) Dm2<0 Dm2>0 Dm2<0 Dm2>0 Pasquale Migliozzi - INFN Napoli

  19. Mass hierarchy with CNGS? Pasquale Migliozzi - INFN Napoli

  20. q13 in the range 4° to 7° Off-peak exps do not contribute to the q13 business Run JHF with n and NuMI-OA with anti-n will be the optimal solution to lift the d-q13 correlation Run both JHF and NuMI-OA with n in order to measure the sign(Dm223) (e.g. the two exps have different matter effects) V. Barger et al. Phys. Lett. B 560 (2003) 75 P. Huber et al. Nucl. Phys. B 654 (2003) 3 H. Minakata et al. Phys. Rev. D 68 (2003) 013010

  21. Conclusion • Null result at Phase I exps : WARNING!dCP could be huge but hiddenby the choice of the neutrino run. A dangerous manifestation of the ( d-q13) correlation! • The anti-n choice (done after the n run or in parallel by NUMI-OA) ismandatory to take decisions about the Phase II • Positive result at MINOS or CNGS: Great time for oscillation physics!Synergic use of MINOS+ CNGS + JHF + NuMI-OA: • to constrain (d-q13) • to determine the sign of Dm2atm • 4° < q13 < 7° Another great season for Japanese neutrino physics!Signal seen at JPARC. NuMI-OA contribute to precision measurementof (d-q13) in anti-n mode, sign Dm2atm in neutrino mode Pasquale Migliozzi - INFN Napoli

  22. Final remark For a successful future one should first exploit and optimise the present

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