Future precision neutrino experiments and their theoretical Madrid, Spain November 22, 2007 Walter Winter Universität Würzburg

Nov. 22, 2007UAM Walter Winter2 Contents Introduction: Neutrino oscillation phenomenology Introduction: Neutrino oscillation phenomenology Future neutrino oscillation experiments Future neutrino oscillation experiments Why these measurements? Why these measurements? Testing the theory space: One example Testing the theory space: One example Summary Summary

Neutrino oscillation phenomenology

Nov. 22, 2007UAM Walter Winter4 Neutrino oscillations with two flavors Mixing and mass squared difference:  “disappearance”:  “appearance”: Amplitude ~Frequency Baseline: Source - Detector Energy

Nov. 22, 2007UAM Walter Winter5 Three flavor neutrino oscillations (the “standard” picture) Coupling strength:  13 Atmospheric oscillations: Amplitude:  23 Frequency:  m 31 2 Solar oscillations: Amplitude:  12 Frequency:  m 21 2 Suppressed effect:  CP Does this parameter explain the baryon asymmetry? Only upper bound so far! Key to CP violation in the lepton sector! (Super-K, 1998; Chooz, 1999; SNO ; KamLAND 2002) Two large mixing angles!  m 21 2 <<  m 31 2

Nov. 22, 2007UAM Walter Winter6 Neutrino oscillations: current knowledge (Maltoni, Schwetz, Tortola, Valle, )

Nov. 22, 2007UAM Walter Winter7 Matter effects in -oscillations (MSW) Ordinary matter contains electrons, but no ,  Ordinary matter contains electrons, but no ,  Coherent forward scattering in matter has net effect on electron flavor because of CC (rel. phase shift) 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 Matter effects proportional to electron density and baseline Hamiltonian in matter: Hamiltonian in matter: Y: electron fraction ~ 0.5 (electrons per nucleon) (Wolfenstein, 1978; Mikheyev, Smirnov, 1985) Matter potential not CP-/CPT-invariant!

Future neutrino oscillation experiments

Nov. 22, 2007UAM Walter Winter9 A multi-detector reactor experiment … for a “clean” measurement of  13 Double Chooz size Daya Bay size (Minakata et al, 2002; Huber, Lindner, Schwetz, Winter, 2003) Identical detectors, L ~ km Unknown systematics important for large luminosity NB: No sensitivity to  CP and mass hierarchy!

Nov. 22, 2007UAM Walter Winter10 On the way to precision: Neutrino Beams Accelerator- based neutrino source Often: near detector (measures flux times cross sections) Far detector Baseline: L ~ E/  m 2 (Osc. length)   ?

Nov. 22, 2007UAM Walter Winter11 Example: MINOS Measurement of atmospheric parameters with high precision Measurement of atmospheric parameters with high precision Flavor conversion ? Flavor conversion ? Fermilab - Soudan L ~ 735 km Far detector: 5400 t Near detector: 980 t 735 km Beam line

Nov. 22, 2007UAM Walter Winter12 The hunt for  13 Example scenario; bands reflect unknown  CP Example scenario; bands reflect unknown  CP New generation of experiments dominates quickly! New generation of experiments dominates quickly! Neutrino factory: Uses muon decays    + e + e Reach down to sin 2 2  13 ~ (~ osc. amplitude!) Neutrino factory: Uses muon decays    + e + e Reach down to sin 2 2  13 ~ (~ osc. amplitude!) O(1,000,000) events/year in 50 kt 3000 km from source! (from: FNAL Proton Driver Study) GLoBES 2005

Nov. 22, 2007UAM Walter Winter13 Neutrino factory Ultimate “high precision” instrument!? Ultimate “high precision” instrument!? Muon decays in straight sections of storage ring Muon decays in straight sections of storage ring Technical challenges: Target power, muon cooling, charge identification, maybe steep decay tunnels Technical challenges: Target power, muon cooling, charge identification, maybe steep decay tunnels (from: CERN Yellow Report ) p Target , K  Decays  -Accelerator  Cooling “Wrong sign” “Right sign” “Wrong sign” “Right sign” (Geer, 1997; de Rujula, Gavela, Hernandez, 1998; Cervera et al, 2000)

Nov. 22, 2007UAM Walter Winter14 IDS-NF launched at NuFact 07 International 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: [hep-ph]) Successor of the International Scoping Study for a „future neutrino factory and superbeam facility“: Physics case made in physics WG report (370 pp) (arXiv: [hep-ph]) Initiative from ~ to present a design report, schedule, cost estimate, risk assessment for a neutrino factory Initiative from ~ to present a design report, schedule, cost estimate, risk assessment for a neutrino factory In Europe: Close connection to „Euro us“ proposal within the FP 07; for UAM: Andrea Donini (deputy coordinator of WP 6); in Spain also: IFIC Valencia In Europe: Close connection to „Euro us“ 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? In the US: „Muon collider task force“ - How can a neutrino factory be „upgraded“ to a muon collider?

Nov. 22, 2007UAM Walter Winter15 Appearance channels:  e  Complicated, but all interesting information there:  13,  CP, mass hierarchy (via A) (see e.g. Akhmedov, Johansson, Lindner, Ohlsson, Schwetz, 2004) Anti-nus

Nov. 22, 2007UAM Walter Winter16 Problems with degeneracies Connected (green) or disconnected (yellow) degenerate solutions in parameter space Connected (green) or disconnected (yellow) degenerate solutions in parameter space Affect measurements Example:  13 -sensitivity Affect measurements Example:  13 -sensitivity (Huber, Lindner, Winter, 2002) Discrete degeneracies: ( ,  13 )-degeneracy (Burguet-Castell et al, 2001) sgn-degeneracy (Minakata, Nunokawa, 2001) (  23,  /2-  23 )-degeneracy (Fogli, Lisi, 1996) Discrete degeneracies: ( ,  13 )-degeneracy (Burguet-Castell et al, 2001) sgn-degeneracy (Minakata, Nunokawa, 2001) (  23,  /2-  23 )-degeneracy (Fogli, Lisi, 1996)

Nov. 22, 2007UAM Walter Winter17 Resolving degeneracies Example: „Magic“ baseline for NF L= ~ 4000 km (CP) + ~7500 km (degs) today baseline configuration of a neutrino factory (ISS report, arXiv: ) L= ~ 4000 km (CP) + ~7500 km (degs) today baseline configuration of a neutrino factory (ISS report, arXiv: ) (Huber, Winter, 2003)

Nov. 22, 2007UAM Walter Winter18 NF precision measurements (Gandhi, Winter, 2006)(Huber, Lindner, Winter, 2004)  CP precision  13 precision  CP dep. 33 corresponds to ~ 5 to 10 degrees at 1 

Why these measurements?

Nov. 22, 2007UAM Walter Winter20 Lepton masses and the seesaw Charged lepton mass terms Effective neutrino mass terms cf., CC interaction Rotates left-handed fields Block-diag. Eff. 3x3 case

Nov. 22, 2007UAM Walter Winter21 Experiments vs. neutrino mass models Mass models describe masses and mixings (mass matrices) by symmetries, GUTs, anarchy arguments, etc. Mass models describe masses and mixings (mass matrices) by symmetries, GUTs, anarchy arguments, etc. From that: predictions for observables From that: predictions for observables Example: Literature research for  13 Example: Literature research for  13 (Albright, Chen, 2006) Peak generic or biased? Experiments provide important hints for theory

Nov. 22, 2007UAM Walter Winter22 Performance indicators for theory What observables test the theory space most efficiently? Magnitude of  13 (see before!) Magnitude of  13 (see before!) Mass hierarchy (strongly affects textures) Mass hierarchy (strongly affects textures) Deviations from max. mixings (  -  symmetry?) Deviations from max. mixings (  -  symmetry?) |sin 2  12 -1/3| (tribimaximal mixings?) |sin 2  12 -1/3| (tribimaximal mixings?) |sin  CP -1| (CP violation) (leptogenesis?) |sin  CP -1| (CP violation) (leptogenesis?)  C +  12 ~  /4 ~  23 (indicator for quark-lepton unification?)  C +  12 ~  /4 ~  23 (indicator for quark-lepton unification?) (Antusch et al, hep-ph/ ) Connection with quark sector!

Nov. 22, 2007UAM Walter Winter23 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 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  13 preferred;  CP ~  (CP conservation) From complex matrices: maximal mixings, large  13 preferred;  CP ~  (CP conservation) Can one combine such an approch with very simple=generic assumptions on flavor symmetries, quark-lepton unification etc.? Can one combine such an approch with very simple=generic assumptions on flavor symmetries, quark-lepton unification etc.? (Haba, Murayama, 2000) (12, 13, 23)

Testing the theory space: One example

Nov. 22, 2007UAM Walter Winter25 Bottom-up approach: Procedure A conventional approach: A conventional approach: Bottom-up approach: Bottom-up approach: Theory (e.g. GUT, flavor symmetry) Yukawa coupling structure Fit (order one coeff.) to data!? Theory (e.g. flavor symmetry) Yukawa coupling structure Yukawa couplings with order one coeff. Connection to observables ModelTextureRealization Generic assumptions (e.g. QLC) m : 11 : n Diag., many d.o.f. No diag., reduce d.o.f. by knowledge on data

Nov. 22, 2007UAM Walter Winter26 Benefits of bottom-up approach Key features: 1. Construct all possibilities given a set of generic assumptions  New textures, models, etc. 2. Learn something about parameter space  Spin-off: Learn how experiments can most efficiently test this parameter space! Very generic assumptions Automated procedure: generate all possibilities Interpretation/ analysis Select solutions compatible with data Cannot foresee the outcome! Low bias!?

Nov. 22, 2007UAM Walter Winter27 Quark versus lepton mixings Basic idea: Use same parameterization to compare mixing angles, phase(s) 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? Why should that be interesting at all if there was no connection suspected between the two sectors? < V CKM U PMNS

Nov. 22, 2007UAM Walter Winter28 Generic assumptions from quark-lepton unification? Phenomenological hint e.g. („Quark-Lepton- Complementarity“ - QLC) Phenomenological hint e.g. („Quark-Lepton- Complementarity“ - QLC) (Petcov, Smirnov, 1993; Smirnov, 2004; Raidal, 2004; Minakata, Smirnov, 2004; others) Is there one quantity  ~  C which describes all mixings and hierarchies? Is there one quantity  ~  C which describes all mixings and hierarchies? Remnant of a unified theory? Remnant of a unified theory? Lepton Sector Quark Sector Symmetry breaking(s) E Unified theory  

Nov. 22, 2007UAM Walter Winter29 Manifestation of  Mass hierarchies of quarks/charged leptons: m u :m c :m t =  6 :  4 :1, m d :m s :m b =  4 :  2 :1, m e :m  :m  =  4 :  2 :1 (motivated by flavor symmetries) Mass hierarchies of quarks/charged leptons: m u :m c :m t =  6 :  4 :1, m d :m s :m b =  4 :  2 :1, m e :m  :m  =  4 :  2 :1 (motivated by flavor symmetries) Neutrino masses: m 1 :m 2 :m 3 ~  2 :  :1, 1:1:  oder 1:1:1 Neutrino masses: m 1 :m 2 :m 3 ~  2 :  :1, 1:1:  oder 1:1:1 Mixings Example: Mixings Example: 1 3333 1 2222 3333 22221 V CKM ~ U PMNS ~ V CKM + U bimax ? Combination of  and max. mixings?  Generic assumption!

Nov. 22, 2007UAM Walter Winter30 Extended QLC in the 3x3-case 1. Generate all possible (real) U l, U with mixing angles (262,144) 2. Calculate U PMNS and read off mixing angles; select only realizations compatible with data (2,468) 3. Calculate mass matrices using eigenvalues from last slide with and determine leading order coefficients  a few Textures (19)  No diagonalization necessary Cutoff given by current precision ~  2 Example: 1

Nov. 22, 2007UAM Walter Winter31 New textures from extended QLC New sum rules and systematic classification of textures New sum rules and systematic classification of textures Example: „Diamond“ textures with new sum rules, such as (includes coefficients from underlying realizations) Can be obtained from two large mixing angles in the lepton sector! „Entangled“ mixings? Example: „Diamond“ textures with new sum rules, such as (includes coefficients from underlying realizations) Can be obtained from two large mixing angles in the lepton sector! „Entangled“ mixings? (Plentinger, Seidl, Winter, hep-ph/ )

Nov. 22, 2007UAM Walter Winter32 Distribution of observables Parameter space analysis based on realizations Parameter space analysis based on realizations Large   3 preferred Large   3 preferred Compared to the GUT literature: Some realizations with very small sin 2 2  13 ~ Compared to the GUT literature: Some realizations with very small sin 2 2  13 ~ (Plentinger, Seidl, Winter, hep-ph/ ) Tribimaximal?

Nov. 22, 2007UAM Walter Winter33 How exps affect this parameter space Strong pressure from  13 and  12 measurements Strong pressure from  13 and  12 measurements  12 can emerge as a combination between maximal mixing and  C !  „Extended“ QLC  12 can emerge as a combination between maximal mixing and  C !  „Extended“ QLC (Plentinger, Seidl, Winter, hep-ph/ )

Nov. 22, 2007UAM Walter Winter34 Introducing complex phases Vary all complex phases with uniform distributions Vary all complex phases with uniform distributions Calculate all valid realizations and textures (n:1)  Landscape interpretation with some mass structure? (see e.g. Hall, Salem, Watari, 2007) Calculate all valid realizations and textures (n:1)  Landscape interpretation with some mass structure? (see e.g. Hall, Salem, Watari, 2007) Want ~  C -precision (~12 o ) for  CP ? Want ~  C -precision (~12 o ) for  CP ? (Winter, 2007) (U l ≠ 1)

Nov. 22, 2007UAM Walter Winter35 Distributions in the  13 -  CP -plane delta ~ theta_C necessary! delta ~ theta_C necessary! (Winter, 2007; beta beam from Burguet-Castell et al, 2005) Clusters contain 50% of all realizations of one texture

Nov. 22, 2007UAM Walter Winter36 The seesaw in extended QLC (Plentinger, Seidl, Winter, arXiv: ) Generate all mixing angles and hierarchies by Only real cases!

Nov. 22, 2007UAM Walter Winter37 See-saw statistics (NH) … based on realizations Often: Mild hierarchies in M R found Resonant leptogenesis? Flavor effects? Often: Mild hierarchies in M R found Resonant leptogenesis? Flavor effects? Charged lepton mixing is, in general, not small! Charged lepton mixing is, in general, not small! Special cases rare, except from M R ~ diagonal! Special cases rare, except from M R ~ diagonal! (Plentinger, Seidl, Winter, arXiv: )

Nov. 22, 2007UAM Walter Winter38 Seesaw-Textures (NH,  13 small) Obtain 1981 texture sets {M l, M D, M R } Obtain 1981 texture sets {M l, M D, M R } (Plentinger, Seidl, Winter, arXiv: ; )  = 0,  2

Nov. 22, 2007UAM Walter Winter39 What are the textures good for? Example: Froggatt-Nielsen mechanism

Nov. 22, 2007UAM Walter Winter40 Outlook: Towards model building Example: Froggatt-Nielsen mechanism Use M-fold Z N product flavor symmetry Example: Froggatt-Nielsen mechanism Use M-fold Z N product flavor symmetry   -powers are determined by flavor symmetry quantum numbers of left- and right-handed fermions! How much complexity is actually needed to reproduce our textures?  Depends on structure in textures! How much complexity is actually needed to reproduce our textures?  Depends on structure in textures! (Plentinger, Seidl, Winter, in preparation) PRELIMINARY Our 1981 textures PRELIMINARY Systematic test of all possible charge assignments!

Nov. 22, 2007UAM Walter Winter41 One example Z 5 x Z 4 x Z 3 Z 5 x Z 4 x Z 3 Case 205, Texture 1679 Case 205, Texture 1679 ( Quantum numbers (example): 1 c, 2 c, 3 c :(1,0,1), (0,3,2), (3,3,0) l 1, l 2, l 3 : (4,3,2), (0,1,0), (0,2,2) e 1 c, e 2 c, e 3 c : (3,0,2), (2,0,2), (1,2,0) Quantum numbers (example): 1 c, 2 c, 3 c :(1,0,1), (0,3,2), (3,3,0) l 1, l 2, l 3 : (4,3,2), (0,1,0), (0,2,2) e 1 c, e 2 c, e 3 c : (3,0,2), (2,0,2), (1,2,0) Realization: can e.g. be realized with (  12,  13,  23 ) ~ (33 o,0.2 o,52 o ) Realization: can e.g. be realized with (  12,  13,  23 ) ~ (33 o,0.2 o,52 o ) (Plentinger, Seidl, Winter, in preparation) Absorb overall scaling factor in absolute scale! 0 ~  3,  4, …!

Nov. 22, 2007UAM Walter Winter42 Summary Future experiments may test sin 2 2  13 down to ~ and measure  CP at the level of about 10 degrees (1  for sin 2 2  13 = ) Future experiments may test sin 2 2  13 down to ~ and measure  CP at the level of about 10 degrees (1  for sin 2 2  13 = ) We parameterize U PMNS in the same way as V CKM  What can we learn from a comparison? We parameterize U PMNS in the same way as V CKM  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 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  ~  C : Want e.g. Cabibbo-angle precision for  CP ? Extended QLC is one such assumption which connects neutrino physics with the quark sector via  ~  C : Want e.g. Cabibbo-angle precision for  CP ? Why use more complicated non-Abelian flavor symmetries if one can generate thousands of models from a priori very simple assumptions? Why use more complicated non-Abelian flavor symmetries if one can generate thousands of models from a priori very simple assumptions?