Future precision neutrino experiments Future precision neutrino experiments and their theoretical motivationand their theoretical motivation

@UAM@UAMMadrid, SpainMadrid, Spain

November 22, 2007November 22, 2007

Walter WinterWalter WinterUniversität WürzburgUniversität Würzburg

Nov. 22, 2007 UAM 2007 - Walter Winter 2

ContentsContents

Introduction: Introduction: Neutrino oscillation phenomenologyNeutrino oscillation phenomenology

Future neutrino oscillation experiments Future neutrino oscillation experiments Why these measurements?Why these measurements? Testing the theory space: One exampleTesting the theory space: One example SummarySummary

Neutrino oscillation phenomenologyNeutrino oscillation phenomenology

Nov. 22, 2007 UAM 2007 - Walter Winter 4

Neutrino oscillations with two flavorsNeutrino oscillations with two flavorsMixing and mass squared difference:Mixing and mass squared difference:

“disappearance”: “disappearance”:

“appearance”: “appearance”:

Amplitude~Frequency

Baseline: Source - Detector

Energy

Nov. 22, 2007 UAM 2007 - Walter Winter 5

Three flavor neutrino oscillationsThree flavor neutrino oscillations(the “standard” picture)(the “standard” picture)

Coupling strength: 13

Atmosphericoscillations:Amplitude: 23

Frequency: m312

Solaroscillations:Amplitude: 12

Frequency: m212

Suppressed effect: CP

Does this parameter explain the baryon

asymmetry?

Only upper bound so far!Key to CP violationin the lepton sector!

(Super-K, 1998;Chooz, 1999; SNO 2001+2002; KamLAND 2002)

Two large mixing angles!m21

2 << m312

Nov. 22, 2007 UAM 2007 - Walter Winter 6

Neutrino oscillations: current knowledgeNeutrino oscillations: current knowledge

(Maltoni, Schwetz, Tortola, Valle, 2004-2007)

Nov. 22, 2007 UAM 2007 - Walter Winter 7

Matter effects in Matter effects in -oscillations (MSW)-oscillations (MSW) Ordinary matter Ordinary matter

contains electrons, contains electrons, but no but no ,,

Coherent forward Coherent forward scattering in matter scattering in matter has net effect on electron flavor because of CC (rel. phase shift)has net effect on electron flavor because of CC (rel. phase shift)

Matter effects proportional to electron density and Matter effects proportional to electron density and baselinebaseline 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 oscillationFuture neutrino oscillationexperimentsexperiments

Nov. 22, 2007 UAM 2007 - Walter Winter 9

A multi-detector reactor experimentA multi-detector reactor experiment… for a “clean” measurement of … for a “clean” measurement of 1313

Double Choozsize

Daya Baysize

(Minakata et al, 2002; Huber, Lindner, Schwetz, Winter, 2003)

Identical detectors, L ~ 1.1-1.7 km

Unknownsystematics

important for large

luminosity

NB: No sensitivity to CP and

mass hierarchy!

Nov. 22, 2007 UAM 2007 - Walter Winter 10

On the way to precision:On the way to precision:Neutrino BeamsNeutrino Beams

Accelerator-based neutrino

source

Often: near detector (measures flux times

cross sections)

Far detector

Baseline: L ~ E/m2

(Osc. length)

?

Nov. 22, 2007 UAM 2007 - Walter Winter 11

Example: MINOSExample: MINOS Measurement of atmosphericMeasurement of atmospheric

parameters with high precisionparameters with high precision Flavor conversion ?Flavor conversion ? Fermilab - Soudan

L ~ 735 km

Far detector: 5400 tNear detector: 980 t

735 km

Beam line

Nov. 22, 2007 UAM 2007 - Walter Winter 12

The hunt for The hunt for 1313

Example scenario; bands Example scenario; bands reflect unknown reflect unknown CPCP

New generation of New generation of experiments dominates experiments dominates quickly!quickly!

Neutrino factory:Neutrino factory:Uses muon decaysUses muon decays + + ee + e + e

Reach down to Reach down to sinsin22221313 ~ 10 ~ 10-5 -5 -- 1010-4 -4

(~ osc. amplitude!)(~ osc. amplitude!)

O(1,000,000) events/yearO(1,000,000) events/yearin 50 kt detector @ 3000 in 50 kt detector @ 3000 km from source!km from source!(from: FNAL Proton Driver Study)

GLoBES 2005

Nov. 22, 2007 UAM 2007 - Walter Winter 13

Neutrino factoryNeutrino factory Ultimate “high precision” instrument!?Ultimate “high precision” instrument!? Muon decays in straight sections of storage Muon decays in straight sections of storage

ringring Technical challenges: Target power, muon Technical challenges: Target power, muon

cooling, charge identification, maybe steep cooling, charge identification, maybe steep decay tunnelsdecay 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, 2007 UAM 2007 - Walter Winter 14

IDS-NF launched at NuFact 07IDS-NF launched at NuFact 07International design study for a neutrino factoryInternational design study for a neutrino factory

Successor of the International Scoping Study for a „future Successor of the International Scoping Study for a „future neutrino factory and superbeam facility“:neutrino factory and superbeam facility“:Physics case made in physics WG report (370 pp) Physics case made in physics WG report (370 pp) (arXiv:0710.4947 [hep-ph])(arXiv:0710.4947 [hep-ph])

Initiative from ~ 2007-2012 to present a design report, Initiative from ~ 2007-2012 to present a design report, schedule, cost estimate, risk assessment for a neutrino schedule, cost estimate, risk assessment for a neutrino factoryfactory

In Europe: Close connection to „EuroIn Europe: Close connection to „Eurous“ proposal us“ proposal within the FP 07; for UAM: within the FP 07; for UAM: Andrea DoniniAndrea Donini (deputy (deputy coordinator of WP 6); in Spain also: IFIC Valencia coordinator of WP 6); in Spain also: IFIC Valencia

In the US: „Muon collider task force“ - How can a neutrino In the US: „Muon collider task force“ - How can a neutrino factory be „upgraded“ to a muon collider?factory be „upgraded“ to a muon collider?

Nov. 22, 2007 UAM 2007 - Walter Winter 15

Appearance channels: Appearance channels: ee

Complicated, but all interesting information there: Complicated, but all interesting information there: 1313, , CPCP, mass hierarchy (via A), mass hierarchy (via A)

(see e.g. Akhmedov, Johansson, Lindner, Ohlsson, Schwetz, 2004)

Anti-nus

Nov. 22, 2007 UAM 2007 - Walter Winter 16

Problems with degeneraciesProblems with degeneracies Connected (green) or Connected (green) or

disconnected (yellow) disconnected (yellow) degenerate solutions in degenerate solutions in parameter spaceparameter space

Affect measurementsAffect measurementsExample: Example: 1313-sensitivity-sensitivity

(Huber, Lindner, Winter, 2002)(Huber, Lindner, Winter, 2002)

Discrete degeneracies: Discrete degeneracies: ((,,1313)-degeneracy)-degeneracy(Burguet-Castell et al, 2001)(Burguet-Castell et al, 2001)

sgn-degeneracy sgn-degeneracy (Minakata, Nunokawa, 2001)(Minakata, Nunokawa, 2001)

((2323,,/2-/2-2323)-degeneracy )-degeneracy (Fogli, Lisi, 1996)(Fogli, Lisi, 1996)

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Resolving degeneraciesResolving degeneraciesExample: „Magic“ baseline for NFExample: „Magic“ baseline for NF

L= ~ 4000 km (CP) + L= ~ 4000 km (CP) + ~7500 km (degs) today ~7500 km (degs) today baseline configuration of baseline configuration of a neutrino factory a neutrino factory (ISS report, (ISS report, arXiv:0710.4947arXiv:0710.4947))

(Huber, Winter, 2003)(Huber, Winter, 2003)

Nov. 22, 2007 UAM 2007 - Walter Winter 18

NF precision measurementsNF precision measurements

(Gandhi, Winter, 2006)(Huber, Lindner, Winter, 2004)

CP precision 13 precision

CP dep.

3 corresponds to ~ 5 to 10

degrees at 1

Why these measurements?Why these measurements?

Nov. 22, 2007 UAM 2007 - Walter Winter 20

Lepton masses and the seesawLepton masses and the seesaw

Charged leptonmass terms

Effective neutrinomass terms

cf., CC interaction

Rotates left-handedfields

Block-diag.

Eff. 3x3 case

Nov. 22, 2007 UAM 2007 - Walter Winter 21

Experiments vs. neutrino mass models Experiments vs. neutrino mass models Mass models describe masses and mixings (Mass models describe masses and mixings (mass mass

matricesmatrices) by symmetries, GUTs, anarchy arguments, etc.) by symmetries, GUTs, anarchy arguments, etc. From that: predictions for observablesFrom that: predictions for observables Example: Literature research for Example: Literature research for 1313

(Albright, Chen, 2006)

Peak generic or biased?

Experimentsprovide important

hints for theory

Nov. 22, 2007 UAM 2007 - Walter Winter 22

Performance indicators for theoryPerformance indicators for theoryWhat observables test the theory space most efficiently?What observables test the theory space most efficiently?

Magnitude of Magnitude of 1313 (see before!) (see before!) Mass hierarchyMass hierarchy

(strongly affects textures)(strongly affects textures) Deviations from max. mixingsDeviations from max. mixings

((-- symmetry?) symmetry?) |sin|sin221212-1/3|-1/3|

(tribimaximal mixings?)(tribimaximal mixings?) |sin|sinCPCP-1|-1| (CP violation) (CP violation)

(leptogenesis?)(leptogenesis?) CC++1212 ~ ~ /4 ~ /4 ~ 2323

(indicator for quark-lepton (indicator for quark-lepton unification?) unification?)

(Antusch et al, hep-ph/0404268)

Connection with quark sector!

Nov. 22, 2007 UAM 2007 - Walter Winter 23

One example for predictions: AnarchyOne example for predictions: Anarchy Assume: No structure in Yukawa Assume: No structure in Yukawa

couplings, all coefficients random couplings, all coefficients random and O(1) and O(1) oror: Low energy theory is sufficiently : Low energy theory is sufficiently complicated to justify random matricescomplicated to justify random matrices

From complex matrices: maximal From complex matrices: maximal mixings, large mixings, large 1313 preferred; preferred; CPCP ~ ~ (CP conservation) (CP conservation)

Can one combine such an approch Can one combine such an approch with very simple=with very simple=genericgeneric assumptions on flavor symmetries, assumptions on flavor symmetries, quark-lepton unification etc.?quark-lepton unification etc.?

(Haba, Murayama, 2000)

(12, 13, 23)

Testing the theory space:Testing the theory space:One exampleOne example

Nov. 22, 2007 UAM 2007 - Walter Winter 25

Bottom-up approach: ProcedureBottom-up approach: Procedure A conventional approach:A conventional approach:

Bottom-up approach:Bottom-up approach:

Theory(e.g. GUT,

flavor symmetry)

Yukawacouplingstructure

Fit (orderone coeff.)to data!?

Theory(e.g. flavor symmetry)

Yukawacouplingstructure

Yukawacouplingswith orderone coeff.

Connection to observables

Model Texture Realization

Genericassumptions(e.g. QLC)

m : 1 1 : n

Diag.,many d.o.f.

No diag.,reduce d.o.f. by knowledge on data

Nov. 22, 2007 UAM 2007 - Walter Winter 26

Benefits of bottom-up approachBenefits of bottom-up approach

Key features:Key features:

1.1. Construct Construct allall possibilities possibilities given a set of generic given a set of generic assumptions assumptions New textures, models, etc. New textures, models, etc.

2.2. Learn something about Learn something about parameter spaceparameter space Spin-off: Learn how experiments can most Spin-off: Learn how experiments can most efficiently test this parameter space!efficiently test this parameter space!

Very genericassumptions

Automatedprocedure:generate allpossibilities

Interpretation/analysis

Select solutions

compatible with data

Cannot foresee the outcome! Low bias!?

Nov. 22, 2007 UAM 2007 - Walter Winter 27

Quark versus lepton mixingsQuark versus lepton mixings

Basic idea: Use same Basic idea: Use same parameterization parameterization to compare mixing to compare mixing angles, phase(s)angles, phase(s)

Why should that be interesting at all if there was no connection Why should that be interesting at all if there was no connection suspected between the two sectors?suspected between the two sectors?

0.970.97 0.230.23 0.0040.004

0.230.23 0.970.97 0.0420.042

0.0080.008 0.0420.042 1.001.00

0.79-0.880.79-0.88 0.47-0.610.47-0.61 <0.20<0.20

0.19-0.520.19-0.52 0.42-0.730.42-0.73 0.58-0.820.58-0.82

0.20-0.530.20-0.53 0.44-0.740.44-0.74 0.56-0.80.56-0.8

VCKM UPMNS

Nov. 22, 2007 UAM 2007 - Walter Winter 28

Generic assumptions from Generic assumptions from quark-lepton unification?quark-lepton unification?

Phenomenological hint e.g.Phenomenological hint e.g.

(„Quark-Lepton-(„Quark-Lepton-Complementarity“ - QLC)Complementarity“ - QLC)(Petcov, Smirnov, 1993; Smirnov, 2004; Raidal, 2004; Minakata, Smirnov, 2004; others)

Is there Is there oneone quantity quantity ~ ~ CC

which describes all mixings which describes all mixings and hierarchies? and hierarchies?

Remnant of a Remnant of a unified theoryunified theory??

LeptonSector

QuarkSector

Symmetrybreaking(s)

E Unified theory

Nov. 22, 2007 UAM 2007 - Walter Winter 29

Manifestation of Manifestation of Mass hierarchies of quarks/charged leptons: Mass hierarchies of quarks/charged leptons:

mmuu:m:mcc:m:mtt==66::44:1, m:1, mdd:m:mss:m:mbb==44::22:1, :1,

mmee:m:m:m:m==44::22:1 :1 (motivated by flavor symmetries)(motivated by flavor symmetries)

Neutrino masses: mNeutrino masses: m11:m:m22:m:m33~~22:::1, 1:1::1, 1:1: oder 1:1:1 oder 1:1:1

MixingsMixings Example: Example:11 33

11 22

33 22 11

VCKM ~

UPMNS ~ VCKM

+Ubimax ?Combination of

and max. mixings? Generic assumption!

Nov. 22, 2007 UAM 2007 - Walter Winter 30

Extended QLC in the 3x3-caseExtended QLC in the 3x3-case1.1. Generate all possible (real) UGenerate all possible (real) Ull, U, U

with mixing angles with mixing angles (262,144)(262,144)

2.2. Calculate UCalculate UPMNSPMNS and read off mixing angles; and read off mixing angles;select only select only realizationsrealizations compatible with data compatible with data (2,468)(2,468)

3.3. Calculate mass matrices using eigenvalues from last Calculate mass matrices using eigenvalues from last slide withslide with

and determine and determine leading order coefficientsleading order coefficients a few a few Textures Textures (19)(19) No diagonalization necessaryNo diagonalization necessary

Cutoff givenby current

precision ~ 2

Example:

1

Nov. 22, 2007 UAM 2007 - Walter Winter 31

New textures from extended QLCNew textures from extended QLC New sum rules and systematic classificationNew sum rules and systematic classification

of texturesof textures Example: Example:

„Diamond“ textures„Diamond“ textureswith new sum rules, with new sum rules, such assuch as

(includes coefficients from underlying realizations)(includes coefficients from underlying realizations)

Can be obtainedCan be obtained from two large mixing angles in the from two large mixing angles in the lepton sector! lepton sector! „Entangled“ mixings?„Entangled“ mixings?

(Plentinger, Seidl, Winter, hep-ph/0612169)

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Distribution of observablesDistribution of observables Parameter space analysis based on realizationsParameter space analysis based on realizations Large Large 33 preferred preferred Compared to the GUT literature:Compared to the GUT literature:

Some realizations with very small sinSome realizations with very small sin22221313 ~3.3 10 ~3.3 10-5-5

(Plentinger, Seidl, Winter, hep-ph/0612169)

Tribimaximal?

Nov. 22, 2007 UAM 2007 - Walter Winter 33

How exps affect this parameter spaceHow exps affect this parameter space Strong pressure from Strong pressure from 1313 and and 1212 measurements measurements

1212 can emerge as a combination between can emerge as a combination between

maximal mixing and maximal mixing and CC! ! „Extended“ QLC „Extended“ QLC

(Plentinger, Seidl, Winter, hep-ph/0612169)

Nov. 22, 2007 UAM 2007 - Walter Winter 34

Introducing complex phasesIntroducing complex phases Vary all complex Vary all complex

phases with phases with uniformuniform distributionsdistributions

Calculate all validCalculate all validrealizations andrealizations andtextures (n:1)textures (n:1) Landscape Landscape interpretation withinterpretation withsome mass structure?some mass structure?(see e.g. Hall, Salem, Watari, 2007)(see e.g. Hall, Salem, Watari, 2007)

Want ~Want ~CC-precision-precision(~12(~12oo) for ) for CPCP??

(Winter, 2007)

(Ul ≠ 1)

Nov. 22, 2007 UAM 2007 - Walter Winter 35

Distributions in the Distributions in the 1313--CPCP-plane-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, 2007 UAM 2007 - Walter Winter 36

The seesaw in extended QLCThe seesaw in extended QLC(P

lentinger, Seidl, W

inter, arXiv:0707.2379)

Generate allmixing angles and

hierarchies by

Only real cases!

Nov. 22, 2007 UAM 2007 - Walter Winter 37

See-saw statistics (NH)See-saw statistics (NH)… based on realizations… based on realizations

Often: Mild hierarchies Often: Mild hierarchies in Min MRR found found

Resonant leptogenesis?Resonant leptogenesis?Flavor effects?Flavor effects?

Charged lepton mixing is, in general, not small!Charged lepton mixing is, in general, not small!

Special cases Special cases rare, except rare, except from Mfrom MRR ~ ~

diagonal! diagonal! (Plentinger, Seidl, Winter, arXiv:0707.2379)

Nov. 22, 2007 UAM 2007 - Walter Winter 38

Seesaw-Textures Seesaw-Textures (NH, (NH, 1313 small) small)

Obtain 1981 texture sets {MObtain 1981 texture sets {M ll, M, MDD, M, MRR}}

(Plentinger, Seidl, Winter, arXiv:0707.2379;http://theorie.physik.uni-wuerzburg.de/~winter/Resources/SeeSawTex/)

= 0, 2

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What are the textures good for?What are the textures good for?Example: Froggatt-Nielsen mechanismExample: Froggatt-Nielsen mechanism

Nov. 22, 2007 UAM 2007 - Walter Winter 40

Outlook: Towards model buildingOutlook: Towards model building Example:Example:

Froggatt-NielsenFroggatt-Nielsenmechanismmechanism Use M-fold ZUse M-fold ZNN product productflavor symmetryflavor symmetry-powers are determined -powers are determined

by flavor symmetry by flavor symmetry quantum numbers of quantum numbers of left- and right-handed left- and right-handed fermions!fermions!

How much complexity How much complexity is actually needed tois actually needed toreproduce our textures?reproduce our textures? Depends on structure Depends on structurein textures!in textures! (Plentinger, Seidl, Winter, in preparation)

PRELIMINARY

Our 1981 textures

PRELIMINARY

Systematic test ofall possible charge

assignments!

Nov. 22, 2007 UAM 2007 - Walter Winter 41

One exampleOne example ZZ5 5 x Zx Z4 4 x Zx Z33

Case 205, Texture 1679Case 205, Texture 1679(http://theorie.physik.uni-wuerzburg.de/~winter/Resources/SeeSawTex/)

Quantum numbers (example):Quantum numbers (example):11

cc, , 22cc, , 33

cc:: (1,0,1), (0,3,2), (3,3,0)(1,0,1), (0,3,2), (3,3,0)

ll11, l, l22, l, l33: : (4,3,2), (0,1,0), (0,2,2)(4,3,2), (0,1,0), (0,2,2)

ee11cc, e, e22

cc, e, e33cc: : (3,0,2), (2,0,2), (1,2,0)(3,0,2), (2,0,2), (1,2,0)

Realization: can e.g. be realized with Realization: can e.g. be realized with ((1212,,1313,,2323) ~ (33) ~ (33oo,0.2,0.2oo,52,52oo)) (Plentinger, Seidl, Winter, in preparation)

Absorb overallscaling factor inabsolute scale!0 ~ 3, 4, …!

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SummarySummary Future experiments may test sinFuture experiments may test sin22221313 down to ~ 10 down to ~ 10-5-5 and and

measure measure CPCP at the level of about 10 degrees (1 at the level of about 10 degrees (1for for sinsin22221313 = 10 = 10-3-3))

We parameterize UWe parameterize UPMNSPMNS in the same way as V in the same way as VCKMCKM What can we learn from a comparison? What can we learn from a comparison?

One may learn about the theory space and distributions of One may learn about the theory space and distributions of observables from „automated model building“ using observables from „automated model building“ using generic assumptionsgeneric assumptions

Extended QLC is one such assumption which connects Extended QLC is one such assumption which connects neutrino physics with the quark sector via neutrino physics with the quark sector via ~ ~ CC: : Want e.g. Cabibbo-angle precision for Want e.g. Cabibbo-angle precision for CPCP??

Why use more complicated non-Abelian flavor symmetries Why use more complicated non-Abelian flavor symmetries if one can generate thousands of models from if one can generate thousands of models from a prioria priori very very simple assumptions?simple assumptions?