Neutrino physics: Neutrino physics: experiments and experiments and infrastructureinfrastructure

Anselmo Cervera VillanuevaUniversité de GenèveOrsay, 31/01/06

22 Overview Overview

Measuring oscillation parametersCurrent status and objectivesOngoing experiments and near futureLooking for CP violation:

FacilitiesDetectorsStrategies

Open questionsConclusions

33 Measuring osc. parametersMeasuring osc. parameters

295 Km295 Km

EE~0.7 GeV~0.7 GeV

detector

detectorso

urc

eso

urc

e

ee

ee

ee

99.6%

0.4% 0.4%

96%

4%oscillation

ParameterParameter Current Current knowledgeknowledge ChannelChannel ExperimentsExperiments

m223|, 20% error disappearance Atmospheric + K2K

m212, 10% error e or e disapp. Solar + Kamnland

<10o e disapp Chooz (reactor)

Sign of m223 unknown

CP unknown

atmosphericatmospheric

solarsolar

CP CP ee →→ or or → → ee

||mm222323|, |, 2323 disappdisapp

Sign of Sign of mm2223 23 ee →→ or or → → ee ((matter effectsmatter effects))

4E27.1sin2sin

222 Lm

P

→ → e e or or ee →→

T2K13=80

44 Strategies Strategies

oθ 813

e ~

~

e ~

~

oscillations withoutoscillations without ee

oscillations withoscillations with ee

),( ),( 2sin )( 21212

2232313

2 mPmPθP solaratme ),( ) no( 2

2323 mPP atme solaratmCP PP sin2sin 13

science fictionscience fiction

science fictionscience fiction

atmosphericatmospheric solarsolar interferenceinterference

132 2sin θ

LΔm

Eν

223

4

current beamscurrent beamsConventional beamsConventional beamsSuper-beamsSuper-beams

current beamscurrent beams Conventional beamsConventional beamsSuper-beamsSuper-beams

future beamsfuture beams Beta-beamsBeta-beamsNeutrino factoryNeutrino factory

232 2sin θ

LΔm

Eν

212

4

LΔm

Eν

223

4

~e

future beamsfuture beams Neutrino factoryNeutrino factory

future beamsfuture beams Neutrino factoryNeutrino factory

Also CP violation

Also CP violation

55

The sun and the atmosphere cannot tell us much more

We need hand made neutrinos:We can chose the right L and the right E. L/E is not the relevant quantity anymore because of matter effects

To know the beam composition and energy: with near detectorswith near detectors

reduce systematic errors

Look at the right channel: appropriate neutrino sourceneutrino source

Build large detectors (the statistics is essential)

Chose the right technology for the channel to detect:MuonsMuons: segmented calorimeters, water cherenkov, liquid argon

ElectronsElectrons: low Z calorimeters, water cherenkov, liquid argon

TausTaus: emulsions

And very important:A good knowledge of neutrino cross sections is crucial

near detectorsnear detectors

66 In 5 years from now In 5 years from now

Conventional neutrino beams: long baseline experiments

NUMI beam: NUMI beam: MINOSMINOS(2005)(2005) CNGS beam: CNGS beam: OPERAOPERA (2006) (2006)

Nuclear reactor experiments

Measure preciselyMeasure preciselythe atmospheric parameters the atmospheric parameters

Demonstrate

Explore Explore 13 13 down todown to 5500

sinsin22(2(21313)~0.03)~0.03

Double-Chooz Double-Chooz (2007)(2007)

Magnetised iron calorimeter Emulsions

77 Super-beams (2009-2015)Super-beams (2009-2015)Off-axes technique:

narrow band beamImprove beam purity

Increase beam powerAdjust L/E to the oscillation maximum

go down to go down to 1313~3~300

or sinor sin22(2(21313)~0.01)~0.01

Upgraded NuMi beam~14mrad off-axis6.51020 POT/year

(251020 with Proton Driver) 30kton liquid scintill. detector30kton liquid scintill. detector

24% effic. for e detection

Approved by FNAL PAC in April, 2005.

NuMi off axes: NuMi off axes: NOvANOvA (2010) (2010)

JPARC beam: JPARC beam: T2KT2K (2009) (2009)

Farther improve Farther improve

atmospheric parameters atmospheric parameters

88

In the next 10 years 13 could be measured

However these experiments cannot address CP violation

100

50

30

99 CP violationCP violation

asymmetry is a few % and requires excellent flux normalization (neutrino fact., beta beam or off axis beam with not-too-near near detector)

atmsolar

solarCP

ee

eeCP

PP

P

PP

PPA

/2sin

2sin sin

)()(

)()(

132

13

),( ),( 2sin )( 21212

2232313

2 mPmPθP solaratme solaratmCP PP sin2sin 13

atmosphericatmospheric solarsolar interferenceinterference

NOTES:1. sensitivity is more or less independent of 13 down

to max. asymmetry point

2. This is at first maximum! Sensitivity at low values of 13 is better for short baselines, sensitivity at large values of 13 is better for longer baselines (2d max or 3d max.)

3. sign of asymmetry changes with max. number.

for sin = 1

2sin

sin13

solarCP

P

2sinsin 13 CP

-beam example-beam example

1100

We need to produce and measure neutrinos and antineutrinos

Either produce e and detect or vice versa

Problems:The asymmetry is small

Systematic errors need to be very well controlled:Beam composition: for super-beamssuper-beams

Neutrino cross sections: mostly for low energy beamslow energy beams

Detection efficiencies

Correlation with other parameters:13 and sign(m2

23) through matter effects.

Degeneracies: Ambiguities related with lack of knowledge on:Sign(m2

23)

23or 23

1111 Improved Super-beamsImproved Super-beams

T2HK: 4 MW power, MT detector

SPL to Frejus

TRE

CERN SPLLSM-FréjusNear detector

130km

New optimisation: 4 MW;

Energy: 2.2 3.5 GeV

Particle production

440 kTon

1122 Beta-beamsBeta-beams

Pure e or e beam no beam systematicsLow energy beam cross section systematicsUse same detectors as super-beams !!!Could use existing facilities at CERN

189

1810

eνFNe e

eLiHe e63

62

neutrinos of Emax=~600MeV

1133 Neutrino factoryNeutrino factory

50% 50% eno beam systematicsHigh energy beam no cross section systematicsComplicated and expensive: a lot of R&D needed

HARP, MICE, etc

India

CERN layoutCERN layout

1144 Detectors IDetectors I

3D active detector:ImagingCalorimetryCherenkov

Interesting option: very challengingA lot of ongoing R&D

Well known technique: Super-KInteresting for e/ separation in low energy beams

Liquid Argon TPCLiquid Argon TPC

Water CherenkovWater Cherenkov

1155 Detectors IIDetectors II

Full active with liquid scintillator: Super-NOvAOr Sampling Iron CalorimeterThe measurement of the muon charge is essentialInteresting for neutrino factory:

Golden channel

Tracking Magnetised CalorimetersTracking Magnetised Calorimeters

Interesting to solve degeneracies in a neutrino factory:

The CP term has opposite sign

Silver channel

Hybrid emulsion detectorsHybrid emulsion detectors

e

e

A possible detector structure

Stainless steel or LeadFilm

Air Gap

DONUT/OPERA-like target + Emulsion spectrometer

B

~ 3Xo ~10Xo

Low density and long X0 material as targetConservative assumption of 10 µm accuracy in the film by film alignment(0.5mrad angular resolution with 20mm gap structure)

mu

1166 StrategiesStrategies

1. Both (B+SPL) and NUFACT outperform e.g. T2HK on most cases.

2. Combination of B+SPL is really powerful.

3. For sin2213 below 0.01 NUFACT as such outperforms anyone

4. For large values of 13 systematic errors dominate.

1177 Systematics and degeneraciesSystematics and degeneracies

At large values of 13 systematic errors dominate:

Matter effects in neutrino factory

Neutrino cross sections in -beams

Neutrino cross sections and beam flux normalization in super-beams

Same channel 2 baselines (750, 3500)

2 channels: golden and silverSame baseline

Degeneracies can be solved combining different channels or baselines

1188 Some open questions Some open questions

Can we control systematic errors ?Measurements in a near station should be addressed

The neutrino factory studies are not optimised for large 13 since low energy neutrinos (second oscillation maximum) are not detected

One should aim to see the second maximum by lowering the muon detection threshold (from 5 to 1.5 GeV)

Reduce the density of the detectorA magnetised NOvA would do the job

Is it possible to achieve wrong sign electron detection ?

The performances of the different detectors are not know at the same level. Full simulations with input from existing detectors should be carried out for all of them

The measurement of the different parameters requires different optimizations for each facility. That means that probably one needs a combination of facilities

All these questions are being addressed at the moment by ISS/BENE All these questions are being addressed at the moment by ISS/BENE

1199 OutlookOutlook

IF CP violation exists in neutrinos it should be observable

It is possible to conceive a major neutrino infrastructure for Europe with outstanding performance (e.g. the CP violating phase would be observed over most of the phase space)

The detailed choice should be based on reasonable cost estimate and performance evaluation, and the range in 13.

effort is now targeted at: for NUFACT: improving matter effects determination and the detectors concepts for the low energy option: understanding the sources of systematic errors when dealing with low energy events

Some encouraging progress has already been made but a detector design study with extensive prototyping will be needed to be in a position to make serious proposals by the end of this decade.

Nowadays the neutrino is the less known of the elementary particles and a clear gate to new physics

Priority must be for neutrino facilities