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Future precision neutrino experiments and their theoretical motivation

Future precision neutrino experiments and their theoretical motivation

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Future precision neutrino experiments and their theoretical motivation

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  1. Future precision neutrino experiments and their theoretical motivation @UAM Madrid, Spain November 22, 2007Walter Winter Universität Würzburg

  2. Contents • Introduction: Neutrino oscillation phenomenology • Future neutrino oscillation experiments • Why these measurements? • Testing the theory space: One example • Summary UAM 2007 - Walter Winter

  3. Neutrino oscillation phenomenology

  4. Neutrino oscillations with two flavors Mixing and mass squared difference:na “disappearance”:nb “appearance”: ~Frequency Amplitude Baseline: Source - Detector Energy UAM 2007 - Walter Winter

  5. Three flavor neutrino oscillations(the “standard” picture) Atmosphericoscillations:Amplitude: q23Frequency: Dm312 Two large mixing angles!Dm212 << Dm312 Solaroscillations:Amplitude: q12Frequency: Dm212 Coupling strength: q13 Suppressed effect: dCP (Super-K, 1998;Chooz, 1999; SNO 2001+2002; KamLAND 2002) Only upper bound so far!Key to CP violationin the lepton sector! Does this parameter explain the baryon asymmetry? UAM 2007 - Walter Winter

  6. Neutrino oscillations: current knowledge (Maltoni, Schwetz, Tortola, Valle, 2004-2007) UAM 2007 - Walter Winter

  7. Matter effects in n-oscillations (MSW) • Ordinary matter contains electrons, but no m, t • Coherent forward scattering in matter has net effect on electron flavor because of CC (rel. phase shift) • Matter effects proportional to electron density and baseline • Hamiltonian in matter: (Wolfenstein, 1978; Mikheyev, Smirnov, 1985) Y: electron fraction ~ 0.5 (electrons per nucleon) Matter potential not CP-/CPT-invariant! UAM 2007 - Walter Winter

  8. Future neutrino oscillationexperiments

  9. A multi-detector reactor experiment… for a “clean” measurement of q13 Identical detectors, L ~ 1.1-1.7 km Daya Baysize Unknownsystematics important for large luminosity NB: No sensitivity to dCP andmass hierarchy! Double Choozsize (Minakata et al, 2002;Huber, Lindner, Schwetz, Winter, 2003) UAM 2007 - Walter Winter

  10. On the way to precision:Neutrino Beams nb? Accelerator-based neutrinosource na Far detector Often: near detector (measures flux times cross sections) Baseline: L ~ E/Dm2 (Osc. length) UAM 2007 - Walter Winter

  11. Example: MINOS • Measurement of atmosphericparameters with high precision • Flavor conversion ? Fermilab - SoudanL ~ 735 km Beam line Near detector: 980 t Far detector: 5400 t 735 km UAM 2007 - Walter Winter

  12. The hunt for q13 • Example scenario; bands reflect unknown dCP • New generation of experiments dominates quickly! • Neutrino factory:Uses muon decaysm nm + ne + eReach down to sin22q13 ~ 10-5 -10-4 (~ osc. amplitude!) O(1,000,000) events/yearin 50 kt detector @ 3000 km from source! GLoBES 2005 (from: FNAL Proton Driver Study) UAM 2007 - Walter Winter

  13. Neutrino factory • Ultimate “high precision” instrument!? • Muon decays in straight sections of storage ring • Technical challenges: Target power, muon cooling, charge identification, maybe steep decay tunnels Decays Target Cooling m-Accelerator m n p p, K m “Right sign” “Wrong sign” “Right sign” “Wrong sign” (from: CERN Yellow Report ) (Geer, 1997; de Rujula, Gavela, Hernandez, 1998; Cervera et al, 2000) UAM 2007 - Walter Winter

  14. IDS-NF launched at NuFact 07International design study for a neutrino factory • Successor of the International Scoping Study for a „future neutrino factory and superbeam facility“:Physics case made in physics WG report (370 pp) (arXiv:0710.4947 [hep-ph]) • Initiative from ~ 2007-2012 to present a design report, schedule, cost estimate, risk assessment for a neutrino factory • In Europe: Close connection to „Euronus“ proposal within the FP 07; for UAM: Andrea Donini (deputy coordinator of WP 6); in Spain also: IFIC Valencia • In the US: „Muon collider task force“ - How can a neutrino factory be „upgraded“ to a muon collider? UAM 2007 - Walter Winter

  15. Appearance channels: nmne • Complicated, but all interesting information there: q13, dCP, mass hierarchy (via A) Anti-nus (see e.g. Akhmedov, Johansson, Lindner, Ohlsson, Schwetz, 2004) UAM 2007 - Walter Winter

  16. Problems with degeneracies • Connected (green) or disconnected (yellow) degenerate solutions in parameter space • Affect measurementsExample: q13-sensitivity • Discrete degeneracies: (d,q13)-degeneracy(Burguet-Castell et al, 2001)sgn-degeneracy (Minakata, Nunokawa, 2001)(q23,p/2-q23)-degeneracy (Fogli, Lisi, 1996) (Huber, Lindner, Winter, 2002) UAM 2007 - Walter Winter

  17. Resolving degeneraciesExample: „Magic“ baseline for NF • L= ~ 4000 km (CP) + ~7500 km (degs) today baseline configuration of a neutrino factory (ISS report, arXiv:0710.4947) (Huber, Winter, 2003) UAM 2007 - Walter Winter

  18. NF precision measurements dCP precision q13 precision 3s corresponds to ~ 5 to 10 degrees at 1s dCP dep. (Huber, Lindner, Winter, 2004) (Gandhi, Winter, 2006) UAM 2007 - Walter Winter

  19. Why these measurements?

  20. Lepton masses and the seesaw Block-diag. Eff. 3x3 case Charged leptonmass terms Effective neutrinomass terms cf., CC interaction Rotates left-handedfields UAM 2007 - Walter Winter

  21. Experiments vs. neutrino mass models • Mass models describe masses and mixings (mass matrices) by symmetries, GUTs, anarchy arguments, etc. • From that: predictions for observables • Example: Literature research for q13 Experimentsprovide importanthints for theory Peak generic or biased? (Albright, Chen, 2006) UAM 2007 - Walter Winter

  22. Performance indicators for theoryWhat observables test the theory space most efficiently? • Magnitude of q13 (see before!) • Mass hierarchy(strongly affects textures) • Deviations from max. mixings(nm-nt symmetry?) • |sin2q12-1/3|(tribimaximal mixings?) • |sindCP-1| (CP violation)(leptogenesis?) • qC+q12 ~ p/4 ~ q23(indicator for quark-lepton unification?) (Antusch et al, hep-ph/0404268) Connection with quark sector! UAM 2007 - Walter Winter

  23. One example for predictions: Anarchy • Assume: No structure in Yukawa couplings, all coefficients random and O(1) or: Low energy theory is sufficiently complicated to justify random matrices • From complex matrices: maximal mixings, large q13 preferred; dCP ~ p (CP conservation) • Can one combine such an approch with very simple=generic assumptions on flavor symmetries, quark-lepton unification etc.? (12, 13, 23) (Haba, Murayama, 2000) UAM 2007 - Walter Winter

  24. Testing the theory space:One example

  25. Bottom-up approach: Procedure Connection to observables Diag.,many d.o.f. • A conventional approach: Theory(e.g. GUT,flavor symmetry) Yukawacouplingstructure Fit (orderone coeff.)to data!? • Bottom-up approach: Model m : 1 Texture 1 : n Realization Theory(e.g. flavor symmetry) Yukawacouplingstructure Yukawacouplingswith orderone coeff. Genericassumptions(e.g. QLC) No diag.,reduce d.o.f. by knowledge on data UAM 2007 - Walter Winter

  26. Benefits of bottom-up approach Very genericassumptions Automatedprocedure:generate allpossibilities Select solutionscompatible with data Interpretation/analysis Key features: • Construct all possibilities given a set of generic assumptions  New textures, models, etc. • Learn something about parameter space Spin-off: Learn how experiments can most efficiently test this parameter space! Cannot foresee the outcome! Low bias!? UAM 2007 - Walter Winter

  27. Quark versus lepton mixings VCKM UPMNS • Basic idea: Use same parameterization to compare mixing angles, phase(s) • Why should that be interesting at all if there was no connection suspected between the two sectors? UAM 2007 - Walter Winter

  28. Generic assumptions from quark-lepton unification? • Phenomenological hint e.g.(„Quark-Lepton-Complementarity“ - QLC)(Petcov, Smirnov, 1993; Smirnov, 2004; Raidal, 2004; Minakata, Smirnov, 2004; others) • Is there one quantity e ~ qCwhich describes all mixings and hierarchies? • Remnant of a unified theory? E Unified theory e Symmetrybreaking(s) e e LeptonSector QuarkSector UAM 2007 - Walter Winter

  29. Manifestation of e ~ 0.2 • Mass hierarchies of quarks/charged leptons: mu:mc:mt=e6:e4:1, md:ms:mb=e4:e2:1, me:mm:mt=e4:e2:1 (motivated by flavor symmetries) • Neutrino masses: m1:m2:m3~e2:e:1, 1:1:e oder 1:1:1 • Mixings Example: UPMNS ~ VCKM+Ubimax ? VCKM ~ Combination ofe and max. mixings? Generic assumption! UAM 2007 - Walter Winter

  30. Extended QLC in the 3x3-case Cutoff givenby current precision ~ e2 • Generate all possible (real) Ul, Unwith mixing angles (262,144) • Calculate UPMNS and read off mixing angles;select only realizations compatible with data (2,468) • Calculate mass matrices using eigenvalues from last slide withand determine leading order coefficients a few Textures (19) • No diagonalization necessary 1 Example: UAM 2007 - Walter Winter

  31. New textures from extended QLC • New sum rules and systematic classificationof textures • Example: „Diamond“ textureswith new sum rules, such as(includes coefficients from underlying realizations)Can be obtainedfrom two large mixing angles in the lepton sector! „Entangled“ mixings? (Plentinger, Seidl, Winter, hep-ph/0612169) UAM 2007 - Walter Winter

  32. Distribution of observables • Parameter space analysis based on realizations • Large q13 preferred • Compared to the GUT literature:Some realizations with very small sin22q13 ~3.3 10-5 Tribimaximal? (Plentinger, Seidl, Winter, hep-ph/0612169) UAM 2007 - Walter Winter

  33. How exps affect this parameter space • Strong pressure from q13 and q12 measurements • q12 can emerge as a combination between maximal mixing and qC!  „Extended“ QLC (Plentinger, Seidl, Winter, hep-ph/0612169) UAM 2007 - Walter Winter

  34. Introducing complex phases (Ul ≠ 1) • Vary all complex phases with uniform distributions • Calculate all validrealizations andtextures (n:1) Landscape interpretation withsome mass structure?(see e.g. Hall, Salem, Watari, 2007) • Want ~qC-precision(~12o) for dCP? (Winter, 2007) UAM 2007 - Walter Winter

  35. Distributions in the q13-dCP-plane • delta ~ theta_C necessary! (Winter, 2007; beta beam from Burguet-Castell et al, 2005) Clusters contain 50% of all realizations of one texture UAM 2007 - Walter Winter

  36. The seesaw in extended QLC Generate allmixing angles andhierarchies byOnly real cases! (Plentinger, Seidl, Winter, arXiv:0707.2379) UAM 2007 - Walter Winter

  37. See-saw statistics (NH)… based on realizations • Often: Mild hierarchies in MR foundResonant leptogenesis?Flavor effects? • Charged lepton mixing is, in general, not small! • Special cases rare, except from MR ~ diagonal! (Plentinger, Seidl, Winter, arXiv:0707.2379) UAM 2007 - Walter Winter

  38. Seesaw-Textures (NH, q13 small) • Obtain 1981 texture sets {Ml, MD, MR} (Plentinger, Seidl, Winter, arXiv:0707.2379; http://theorie.physik.uni-wuerzburg.de/~winter/Resources/SeeSawTex/) x = 0, e2 UAM 2007 - Walter Winter

  39. What are the textures good for?Example: Froggatt-Nielsen mechanism UAM 2007 - Walter Winter

  40. Outlook: Towards model building Our 1981 textures • Example:Froggatt-NielsenmechanismUse M-fold ZN productflavor symmetry • e-powers are determined by flavor symmetry quantum numbers of left- and right-handed fermions! • How much complexity is actually needed toreproduce our textures? Depends on structurein textures! Systematic test ofall possible charge assignments! PRELIMINARY PRELIMINARY (Plentinger, Seidl, Winter, in preparation) UAM 2007 - Walter Winter

  41. One example • Z5 x Z4 x Z3 • Case 205, Texture 1679(http://theorie.physik.uni-wuerzburg.de/~winter/Resources/SeeSawTex/) • Quantum numbers (example):n1c, n2c, n3c: (1,0,1), (0,3,2), (3,3,0)l1, l2, l3: (4,3,2), (0,1,0), (0,2,2)e1c, e2c, e3c: (3,0,2), (2,0,2), (1,2,0) • Realization: can e.g. be realized with (q12,q13,q23) ~ (33o,0.2o,52o) Absorb overallscaling factor inabsolute scale!0 ~ e3, e4, …! (Plentinger, Seidl, Winter, in preparation) UAM 2007 - Walter Winter

  42. Summary • Future experiments may test sin22q13 down to ~ 10-5 and measure dCP at the level of about 10 degrees (1s, for sin22q13 = 10-3) • We parameterize UPMNS in the same way as VCKM What can we learn from a comparison? • One may learn about the theory space and distributions of observables from „automated model building“ using generic assumptions • Extended QLC is one such assumption which connects neutrino physics with the quark sector via e ~ qC: Want e.g. Cabibbo-angle precision for dCP? • Why use more complicated non-Abelian flavor symmetries if one can generate thousands of models from a priori very simple assumptions? UAM 2007 - Walter Winter