Physics Working Group INTERNATIONAL NEUTRINO FACTORY AND SUPERBEAM SCOPING STUDY MEETING

1. Physics Working Group INTERNATIONAL NEUTRINO FACTORY AND SUPERBEAM SCOPING STUDY MEETING RAL – 25 April, 2006 Y. Nagashima OSAKA UNIVERSITY Status, prospects and what to do here Acknowledgements: Grateful to all ISS speakers from whom I have taken material.

2. Council members EU: P. Hernandez, S.King, M. Lindner, K. Long (deputy chair),M. Mezzetto US: D.Harris , W.Marciano, L. Roberts, H.Murayama Asia: Y.Nagashima (chair), K. Nakamura, O. Yasuda • Four subgroupsand conveners • Theoretical : S. King • Phenomenological: O. Yasuda • Experimental: K. Long • Muon: L. Roberts(added after CERN meeting)

3. Plenary meetings to date: • CERN: 22 – 24 September, 2005 • KEK: 23 – 26 January, 2006 • Work shops: (Physics) • London: 14 – 21 November, 2005 • Boston: 6-10 March, 2006 • + Phone meetings ~bi weekly This presentation is a summary of KEK and Boston meetings

4. Mission: Theory Subroup • Establish the neutrino physics case • Robust arguments for peers • ‘Elevator pitch’ for decision makers If you happen to be on an elevator with a powerful senator, can you explain why you want to spend ~B$ on your project in 30 seconds ? H.Murayama

5. H.Murayama Many of these questions usually reside in GUT scale and beyond,

6. S.King, P.Huber • It is very difficult to establish a one-to-one correspondence between GUT scale predictions and low energy observables. • A given model, however, usually has generic predictions for low energy observables. • Therefore studying neutrinos allows to gain considerable insight into phenomena which otherwise would be in accessible. • Colliders can not probe this kind of physics, since any effects in scattering amplitudes are suppressed by MGUT, ~O(10-10) at LHC !

7. Top down approaches • The Origin of Flavor Can be tested experimentally Predicted by theory S. King L.Everett More on SUSY E.Arganda • Connection with String theory (P.Langacker) • Minimal see-saw unlikely. • Motivates extended see-saw such as double see-saw • and type II (triplet Higgs).

8. Generation M.C.Chen More on neutrino mass Mass Hierarchy and small mixing in quarks and charged leptons suggestshidden symmetry.Symmetry broken by a VEV ~0.02mu:mc:mt~ md2:ms2:mb2~ me2:mm2:mt2 ~4: 2: 1 • Broken Flavor symmetry H. Murayama Neutrino Different from quark sector ? Many neutrino models

9. * Experimental test ifNew reactor experiment? Gadolinium-loaded SK? Precision comparable to LBL : S. Choubey More on mixing P.Harrison Bottom up approaches * Quark-Lepton Complementarity: Minakata: A.Smirnov inNOVE03

10. M.Fukugita, Tegmark • Neutrinos in Cosmology Leptogenesis, Dark matter, Dark Energy • Mass from Large Scale Structure • Now ∑ mni < 0.4 eV • Future s(∑ mni) ~ 0.04 eV

11. Mass varying neutrino(D.Marfatia) • The neutrino couples to light scalers • A possible candidate for Dark Energy. • Explains all existing data with one sterile neutrino, • yet predicts no LSND effect • A possible signal: Dm2(K2K) ≠Dm2(Atmosphere)

12. Mission – Phenomenological SubroupLook for new physics, survey models and determine necessary precision to: test the unitarity and/or NSI (non standard interaction)

13. M. Sorel Status of 3+2 scheme(Note: 3+1 scheme unlikely) • Can accommodate all data • Implies: Too low BG forsuperbeams, wrong near detector non-osc. assumption • Eventually checked by MiniBOONE !? • If confirmed: Some new interesting physics:

14. Z.Xing Z. Xing Unitarity triangles for lepton sector • In see-saw mechanism: 6x6-Matrix unitary;in all realistic scenarios: • Matter effects change unitarity triangles • Example: Higher Emakes sides comparable; • Easier to calculate area • Easier to establish CP viol. S.Geer J.Lopez More on unitarity

15. A.Friedland Non Standard Interaction: Another reason to do silver channel(nent) S.Antusch O.Yasuda More on new physics predictions

16. Current proton drivers: 108 muons/s(MEG) 4 MW PD: 1011-12 muons/s(PRISM) NF Frontend: 1014 muons/s Muon physics subgroup: • Lepton-flavour violating processes – clear synergy with neutrino oscillations • Neutrino Factory could provide copious source of muons for: • Rare decays: • Flavour-change in scattering Y.Kuno

17. Y.Kuno J.Hisano x L.Roberts K.Jungmann More on muon phys.

18. Kanemura LFV in DIS processes Physics with High Energy Muon beam • Slepton mixing (SUSY) introduces LFV at one loop • t-associated LFVinteresting for Higgs-boson mediated processes • Use DIS process: m N -> t X at neutrino factoryO(102) events for 50 GeV • Also possible with neutrino beam (in preparation)

19. Mission: Experimental subgroup: • Use realistic assumptions on the performance • of accelerator and detector to: • Evaluate and compare performances of • Superbeam Beta beam Neutrino factory First: Recent Progress on Facilities at Large q13

20. P.Fisher Non-Accelerator Physics Blaidwood Reactor Experiment in US2-detctors K.Jungmann More on 2b decay

21. VLBNO All parameters in one experiment ? As good as any other SB experiments. Use wide band beam to measure both 1st and 2nd maximum W.Marciano; Slides: T.Kirk Also H.Kirk, this conference

22. T.Kajita, K.Nakamura sin22q13=0.05 T2KK • Split T2HK detector into two and place one in Korea • Long baseline helps to resolve degeneracy at Kamioka. • T2KK reach comparable or better than NOvA and T2HK combined P.Oddone

23. Reminder: Studies before ISSSB outperforms NF at large q13Very little study on Beta Beam Poor knowledge on systematics (Fig. from Huber, Lindner, Winter, hep-ph/0412199)

24. E.Couce Beta Beam studyFacilities using a Water Cherenkov detector • Principle advantage of betabeam: No intrinsic beam BG • High gamma beta beambest alternative (even “low flux”)

25. P. Huber et al. Comparisons: dCP-q13 SB still outperforms BB and NF At large q13 More on BB E.Couce M.Mezzetto E.Fernandez

26. For small q13 (<0.01) • Superbeams will not address 13, mass hierarchy, or CP violation • A clear case for NF and/or -beam • Yet, many people take an attitude “Wait until what SB finds, NF is useful only for small q13” • However, Will we get the funds to get a neutrino factory even if all previous investments end up “unsuccessful”? (de Gouvêa: )  Investigate NF performance at high q13

27. Huber, Lindner, Rolinec, Winter n Factory Optimization • Use a Better Detector • 100 kton, magetised iron • Two performance assumptions: Threshold moreimportant thanresolution ‘Better’: – Threshold – Resolution ‘Baseline’: – Threshold – Resolution

28. Huber, Lindner, Rolinec, Winter “Magicbaseline” Better Threshold n factory with better detector q13 sensitivity vs L Better detector threshold makes L=2000-3000 km very efficient q13-baseline for exclusion limit

29. Huber, Lindner, Rolinec, Winter, to appear Optimization for large q13 ? : E vs L • Mass hierarchy no problem for L >> 1000 km • CP fraction for CP violation (3s):“Standard” Baseline detector Preliminary • “Optimal appearance”L=1000 km/Em=20 GeVlooks good Better detector W.Winter More on NF

30. W. Better detector: Largeq13 Preliminary • Can compete with the superbeam upgrades (prel.) • Both better Eres and threshold useful at large q13 • Large Dr+better detector prefers shorter baselines (1000-2000km); Em small OK

31. Golden + (Silver, Platinum) Improves sensitivity to CP violation at large q13 Requires its own baseline? P.Huber Golden Now we have a good handle to make NF competitive at large q13 Need to demonstrate with realistic detectors !!

32. W.Winter Interactions: Physics-Detector • “Close the loop”Better detector = key component in large q13 discussion! Need best possible detector with 1. Better low energy efficiences2. Better energy resolution? • Understanding of systematics is critical. Crosssections, Backgrounds, matter distribution, etc. At large q13, it is the limiting factor. • In addition: ne detection, silver channel concepts etc. • Consider what physics the near detector can do ? Good place for new physics ? More on Matter effects crosssection DE, and Eth J.Peltoniemi M.Warner J.Sobczyk

33. W.Winter m+ m- m+ m- silver MB J,Campagne L.Roberts K.Jungmann More on flux, E spectrum m phys. requirement Interactions: Physics-Accelerator • Physics: What muon energy really required? 40 GeV enough for q13, dCP, mass hierarchy ? • Physics: How large can flux uncertainty be? • Storage ring+possible NF program?

34. Avoid too many options mixed up • Discuss different options in one section and choose one “representative” for main line of argumentation? • Need that representative here at RAL if we are to finish in August !!!

35. Our goal: ‘to understand the physics of flavour’ • Requires high precision, high sensitivity measurements of neutrino oscillations • Also LVF in muons, 02 decay. Next 5 years Improve the precision on the atmospheric parameters Measure sin22q13 >0.1, and find CP violation. Next 10 years Demonstrate visibility of sub-leading transitions: Explore sin22q13 down to 0.01 Solve mass hierarchy Then, precision era: when ???????

36. Hep-ex/0509019 Era of sensitivity & precision NF can be a principal actor at the era of precision Timescales: the challenge This graph is made by the same people who believe NF is good only for small q13. Hypnotized, be not ! てぃｓｇｒ

37. K.Long NF roadmap: key decision points • Ambitious, science-driven schedule • Issue now is to establish vibrant R&D programme • Vision for International Design Study phase: • International collaboration; coordinated effort: • Concept development – full system • Accelerator R&D • Detector R&D

38. Summary • We have to show NF is good at large q13, too. • We have to close the loop and come up with a representative plan to achieve the goal in August. • Plan a strategy to accelerate R&D, to achieve early realization of NF.

39. Back up slides

40. Origin of neutrino mass • Effects of physics beyond the SM as effective operators • Can be expanded systematically (Weinberg) • The origin of neutrino mass lies in the lowest order effect of physics and thus the most sensitive probe for new physics at high scales.

42. SUSYmotivated prediction

43. Transition Detection Production New interactions can happen in three places

44. Neutrino Oscillation Appearance Probability

45. 13& reactor experiments • <E> ~ a few MeV  only disappearance experiments  sin2(213) measurement independent of -CP • 1-P(e e) = sin2(213)sin2(m231L/4E) + O(m221/m231) •  weak dependence in m221 • a few MeV e + short baselines  negligible matter effects (O[10-4] )  sin2(213) measurement independent of sign(m213) 13 & beam experiments Appearance probability :  dependences in sin(223), sin(23), sign(m231), -CP phase in [0,2]

46. Conclusions(Reactors：T.Lasserre NO-VE 06) • A new reactor neutrino experiment dedicated to 13 is now being accepted as an important milestone of the neutrino oscillation program • Reactor & Beam programs provide complementary measurements of 13 • An early value of 13 will help to define the optimum CP- program • Several projects of reactor experiment in the pipelines • First generation : sin2(213)~0.02-0.03 • Rate + Shape  Near/Far normalization error dominates (<1% error) • Motionless detectors: Double Chooz, KASKA, RENO • Towards the Second Generation: sin2(213)<0.02 • Movable detectors : Daya-bay, Braidwood and motionless Triple Chooz • Multi-detector phased programs  better cross checks • But what is the systematic error induced by moving ‘100 tons’ detectors? • A further increase of the mass: sin2(213)<0.01 • Movable detectors : Daya-bay, Braidwood • Motionless detectors: Angra , Triple Chooz • Shape only  uncorrelated background dominates !!! • 1000 mwe: Daya Bay, Angra  Need more mass • 450 mwe: Braidwood , Triple Chooz  Need more mass + x >5 times better bkg rejection

47. Ongoing Experiments “After 5 years

48. Super-Beam < 1MW  ~4MW • Expect to measureDm213: • 23%  10% MINOS •  2% T2K, NOvA • Find non-zero q13 • sin22q13 ~ 10-2 Super Beam Phase II • Dm213 　 1% • sin22q13  ~10-3 • mass-hierarchy up tosin22q13 ~ 10-2 • forall value of dNOvA • Search for CP violation

49. Near Future / ”next 10 yrs” P.Huber et al., hep-ph/0403068 NOA Super Beam: opportunity Ｘ1０ improvementover ongoing experiments