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
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