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Simone Gilardoni24 Aprile 2003 DPNC
Introduction to theNeutrino Factory
Simone GilardoniDPNC - Université de Genève
CERN - AB/ABP Division
Simone Gilardoni24 Aprile 2003 DPNC
Neutrino oscillation
Observation: ν into another ν of different flavour
Results: NEUTRINOS HAVE MASSMASS STATES ≠FLAVOUR STATES
Parameters:• 3 masses
– Two ∆m2 differences
• Three mixing angles• One delta phase
−
−
−=
−
−
3
2
1
1212
1212
1313
1313
2323
232310000
0010
0
00
001
ννν
ννν
δ
δ
τ
µ cssc
ces
esc
cssc
i
ie
Simone Gilardoni24 Aprile 2003 DPNC
Neutrino Oscillations
ii
iU νν αα ∑=Mixing described by
For 3-flavour eigenstates U is Maki-Nakagawa-Sakata (MNS):
−−−−−−=
−
231312231312231223131223
231312231312231223131223
1312131213
ccescscseccsssscesssccecssscessccc
Uii
ii
i
δδ
δδ
δ
6 parameters: 3 mixing angles - θ23,θ12 and θ13
CP-violation angle - δ
2 mass differences - ∆m223 and ∆m2
12
Transition probability: ( )
∆=→
νµ θθνν
ELmP e 4
sinsin2sin2232
232
132
Simone Gilardoni24 Aprile 2003 DPNC
Three family oscillation
−
−
−=
−
−
3
2
1
1212
1212
1313
1313
2323
2323
10000
0010
0
00
001
ννν
ννν
δ
δ
τ
µ cssc
ces
esc
cssc
i
ie
Atmospheric Neutrinos
SolarNeutrinos Phase δ CP
• Super-K atm.
• P(νµ→ νµ)
• Maximal mixing
• ∆m2 ≈ 3 10-3 eV2
• L/E = 1 GeV/500 km
• SNO
• P(νe→ νx)
• Large Mixing (LMA)
• Kamland
•L/E ≈ MeV/1.5 1011m
• Limit from CHOOZ
• Goal of next generation of neutrino-beam
•If θ13 is zero, IMPOSSIBLE to observe CP violation
Simone Gilardoni24 Aprile 2003 DPNC
Two friends for Nufact
SNO: D2O detector
Non-νe flux in solar neutrinos
Kamland: νe disappearance from Nuclear Reactor
LMA solution for solar neutrinos
Simone Gilardoni24 Aprile 2003 DPNC
THE last results
G.Fogli et al., PR D66, 010001-406,(2002)
The LMA solution for solar neutrinos is confirmed
The L/E oscillation pattern is confirmed
Simone Gilardoni24 Aprile 2003 DPNC
B.Kaiser
Simone Gilardoni24 Aprile 2003 DPNC
Road Map
• Experiments to look for θ13– Look for νµ→ νe in νµ beam (ICARUS, MINOS)– Off-axis beam (JHF-SK, off axis NUMI)– Low energy SuperBeams
• Experiments to look for CP/T violation or for θ13 (if too small)
– Beta-beams (combined with SuperBeam)
– Neutrino Factory
+++→−++→ eeFNeeeLiHe νν 181866
µννµ +++→+ ee
Simone Gilardoni24 Aprile 2003 DPNC
Sensitivity of Nufact
0.1o 1o 2.5o
5o
13o
Simone Gilardoni24 Aprile 2003 DPNC
JHF ready in 2007
Construction2001~2006 (approved)
JAERI@Tokai-mura(60km N.E. of KEK)
(0.77MW)
Super Conductingmagnet for ν beam line
Near ν detectors@280m and@~2km
1021POT(130day)≡ “1 year”
Simone Gilardoni24 Aprile 2003 DPNC
Far Detectors
48m × 50m ×500m,
Total mass = 1 Mton
1st Phase (2007~, ≥5yrs)Super-Kamiokande(22.5kt)
2nd Phase (201x~?)Hyper-Kamiokande(~1Mt)
Simone Gilardoni24 Aprile 2003 DPNC
Proposal for a CERN - Super Beam
Simone Gilardoni24 Aprile 2003 DPNC
Nufact CERN layout
Simone Gilardoni24 Aprile 2003 DPNC
Nufact FAQ
• Why neutrinos from stored muons:– Pure νµ, νe beam– Switching the helicity by switching the muon sign– Hope for a muon collider (may be… one day…)
• Why high energy ?– High cross section neutrino interaction– Small E/L (50GeV/3500 km)
• Why so many neutrinos?
• Is there someone that can do better before?– See the roadmap
Simone Gilardoni24 Aprile 2003 DPNC
Beam Composition
Nufact Beam WANF Beam
The scales are different !
Simone Gilardoni24 Aprile 2003 DPNC
Energy and flux specs
NuFact near detector
1020 µ decay/year4.0 106 ν CC evt. 1.7 106 ν CC evt.
per kg-year
Minos near detector
3.7 1020 pot/year2.5 106 ν CC evt.0.6 106 ν CC evt.
per ton-year
Physics at far detector
Simone Gilardoni24 Aprile 2003 DPNC
The Holy Grail: any leptonic CP violation?
CP is observable IF:
• sin2θ12 and ∆m212 are large (LMA) and
sin2θ13 small (but not too small…)
• Appearance experiment: P(νe→νµ) – P(νe→νe) is T invariant → CP is conserved
(CP not observable from solar or reactor neutrinos)
termsSolarELmA
PPPP
CPee
ee
+∆
∝=→+→
→−→
13
12212
sinsin)4/sin(sin
)()()()(
θθδ
νννννννν
µµ
µµ
Simone Gilardoni24 Aprile 2003 DPNC
• Measure θ13 via P(νe→νµ) with a precision of 10-3 or setting a limit to 10-6
• Determine via MSW the sign of ∆m2
• Discover and measure the CP violation in the leptonic sector (phase δ)
P(νe→νµ) ≠ P(νe→νµ)
Need of high energy νe:µ+ →e++ νe+ νµ
Physics at a Nufact
Simone Gilardoni24 Aprile 2003 DPNC
µ+ → e++ νµ +νe
νµ → µ−
νµ→ µ+Oscillation
Wrong Sign muons
1016p/s
3 1020 νe/yr3 1020 νµ/yr
0.9 1021 µ/yr
Simone Gilardoni24 Aprile 2003 DPNC
• High Power– LINAC @ 4 MW– Rep. Rate 50 Hz– 2.27 1014 p/pulse spaced by 22.7 nsec (44 MHz)
• Accumulator ring to reduce the pulse length
• CERN interested at least in the low energy part forthe LHC upgrade and the improvement of CNGS
Superconducting Proton Linac
SPL @ 2.2 GeV
Simone Gilardoni24 Aprile 2003 DPNC
Accumulator and Compressor
• Accumulator– Macrobunch with internal 23 ns structure (44 MHz)
MUON BUNCHES KEEP THIS STRUCTURE– Macrobunch Rep. rate: 20 ms (50 Hz)
• Compressor– Microbunch length reduction to from 3.5 ns to 1 ns– Time spread due to Pion decay ≈ 1 ns
Simone Gilardoni24 Aprile 2003 DPNC
PDAC time scheme44 MHz structure
50 Hz
Simone Gilardoni24 Aprile 2003 DPNC
Proposed site
Old ISR tunnel, site of accumulator + bunch compressorRadius = 50 m
Simone Gilardoni24 Aprile 2003 DPNC
Target Nufact• Target:
– Mercury: Z = 80 → short targetLiquid → easy to replace
(v// ≈ 20 m/s)– Dimensions: L ≈ 30 cm, R ≈ 1 cm
40000 ×
4 MW
=
→ 4 MW of proton into a pint of beer
Simone Gilardoni24 Aprile 2003 DPNC
Target experiment
Experiments @BNL and @CERN• Measurements of Hg explosion speed
– Speed of protons >> Speed of sound • Maximum v⊥ ≈ 20 m/s• v// ≈ 3 m/s
Protons
1 cm
Simone Gilardoni24 Aprile 2003 DPNC
Jet test a BNL E-951Event #11 25th April 2001
P-bunch: 2.7×1012 ppb100 nsto = ~ 0.45 ms
Hg- jet : diameter 1.2 cm jet-velocity 2.5 m/sperp. velocity ~ 5 m/s
Picture timing [ms]0.000.754.50
13.00
K. Mc Donald, H. Kirk, A. Fabich
Protons
Simone Gilardoni24 Aprile 2003 DPNC
The Harp experiment Hadron production cross section measurement
Simone Gilardoni24 Aprile 2003 DPNCTop view Side view
Front view
Protons 12 GeV
Be target
Simone Gilardoni24 Aprile 2003 DPNC
Magnetic horn
Protons
Current of 300 kA
To decay channelπ
Hg Target B∝1/RB = 0
Simone Gilardoni24 Aprile 2003 DPNC
First piece of Nufact
Merci à l’ atelier du CERN
Simone Gilardoni24 Aprile 2003 DPNC
Time (arb.)
Decay channel
Ene
rgy
(GeV
)
Solenoid B=1.8 T, L=30 mπ “Life Time” → 18 m @ p=400 MeV/cGeometry
Energy spread reduction needed
π
µ
• Huge Energy spread– Huge velocity spread– LEP σE/E≈ 10-3
– NF σE/E≈ 2• Debunching• Beam type
– β ≈ 0.8– E-t correlation
30 m
Simone Gilardoni24 Aprile 2003 DPNC
Nufact CERN layout
Simone Gilardoni24 Aprile 2003 DPNC
What is a “Phase Rotation”?
• Aim: Reducing the energy spread of a non-relativistic beam
• How: series of RF cavities that
- accelerates low-energy particles
- decelerates high-energy particles
Simone Gilardoni24 Aprile 2003 DPNC
Phase rotation example
100 ≤ E ≤ 300 MeV
30 RF cavities: • 2 MV/m• 44 MHz• L = 1 m • B = 1.8 T
E = 200 ± 50 MeV
time
300
200
100
MeV
Simone Gilardoni24 Aprile 2003 DPNC
88 MHz cavity prototype
Simone Gilardoni24 Aprile 2003 DPNC
Cooling: the problem(transverse phase space)
Accelerato
Accelerator acceptance R ≈ 10 cm, x’ ≈ 0.05 rad
rescaled @ 200 MeV
π and µ after focusing
• Problem: µ → Beam pipe radius of storage ringP⊥ or x’ and x reduction needed: COOLING
Simone Gilardoni24 Aprile 2003 DPNC
Ionization Cooling : the principle
H2 rf
Liquid H2: dE/dx
RF restores only P//: E constant
Beam
sol
sol
Simone Gilardoni24 Aprile 2003 DPNC
2) Focusing :
a) Needed whenx’ reduction comparablewith multiple scatteringb) same rotation center forthe spiral motion. (Rematching)
Cooling : the channel
1) Cooling I : x’ reduction 3) Cooling II : x’ reduction
0i
f
EE'-' ϑ+= if xx
Heating term
‘
0
6.130 X
xpcMeV
βϑ =
H2 has X0= 8.9 m
Cooling works best with high x’
Simone Gilardoni24 Aprile 2003 DPNC
Cooling: the results
Results: phase space density increased by 16(Cooling rate for MICE: 16%)
IN
OUT
Simone Gilardoni24 Aprile 2003 DPNC
Channel engineering design
Simone Gilardoni24 Aprile 2003 DPNC
MICE: Muon Ionisation Cooling Experiment
Proposal to be submitted to RAL before end of the year
Simone Gilardoni24 Aprile 2003 DPNC
Accelerator and Particle physics together
TPG TrackerSciFi Tracker
Example of cooling
Simone Gilardoni24 Aprile 2003 DPNC
Mice roadmap (at RAL?)µ
- STEP I: 2004
STEP II: summer 2005
STEP III: winter 2006
STEP IV: spring 2006
STEP V: fall 2006
STEP VI:2007
Simone Gilardoni24 Aprile 2003 DPNC
Nufact CERN layout
Simone Gilardoni24 Aprile 2003 DPNC
Storage ring
• Two straight sections pointing to two detectors
• Two possible shapes– triangle– bow tie
• Lattice design for beam divergencex’=1/10βγ
→ ν beam divergence dominated byµ decay → θ=1/βγ =mµ/pµ= 2mrad (@ 50 GeV)
• ≥ 25% useful decays per direction
Simone Gilardoni24 Aprile 2003 DPNC
Technical problems
14°
Could you imagine a screw driver falling down from here?
Simone Gilardoni24 Aprile 2003 DPNC
Nufact CERN layout
Simone Gilardoni24 Aprile 2003 DPNC
Around Europe...
• First possible location: Gran Sasso 732 km
• Second location: 3500 km away bestCandidates: Svalbards (Norway)
Gran Canaria (Spain)
Simone Gilardoni24 Aprile 2003 DPNC
Where do you prefer to take shifts?
Simone Gilardoni24 Aprile 2003 DPNC
Why two locations?
From P. Hernandez
•Fit of θ13 and δ a the same time
•No sensitivity at 732 km
•Better to combine with 2810 km
Simone Gilardoni24 Aprile 2003 DPNC
But not too far: no CP sensitivity
L = 7332 km
From P. Hernandez
Simone Gilardoni24 Aprile 2003 DPNC
The world as playground
Simone Gilardoni24 Aprile 2003 DPNC
Far Detector• Iron calorimeter• Magnetized
– Charge discrimination– B = 1 T
• R = 10 m, L = 20 m• Fiducial mass = 40 kT
Baseline
3500 Km
732 Km 3.5 x 107
1.2 x 106
5.9 x 107
2.4 x 106
1.1 x 105
1.0 x 105
νµ CC νe CC νµ signalEvents for 1 year
Simone Gilardoni24 Aprile 2003 DPNC
The neutrino factory golden-measurement is the CP violation. Super-Beam+Beta-Beam are competitive in various ways, including T violation!
General Considerations
δ = 90 deg99%C.L. Curves
(M. Mezzetto, NNN02)
Simone Gilardoni24 Aprile 2003 DPNC
Last question: about financing?
• For the time being our situation is not so good….
BUT….. Some ideas are developing…
Simone Gilardoni24 Aprile 2003 DPNC
Reserve ……………………………………
Simone Gilardoni24 Aprile 2003 DPNC
Total flux of 8B neutrinos
Simone Gilardoni24 Aprile 2003 DPNC
SNO detector
• 1000 ton of D20• 12 m diam. • 9456 PMTs
• Aim: measuring non νe neutrinos in a pure solar νe beam• How? Three possible neutrino reaction in heavy water:
Simone Gilardoni24 Aprile 2003 DPNC
SNO: the Puzzle solution
LMA (Large Mixing Angle) is the preferred solution
SNO Day and Night Energy Spectra Alone
Combining All Experimentaland Solar Model information
Simone Gilardoni24 Aprile 2003 DPNC
Usual attitude for LSND
Simone Gilardoni24 Aprile 2003 DPNC
Summary of experimental results
• Good news:– LMA solar solution
still in good shape– To be confirmed by
KAMLAND • SNO data taking
going on• Super-K rebuilt in
short time
Simone Gilardoni24 Aprile 2003 DPNC
sin22θ13
* Designed for ντ appearance
<0.013JHF-SK
<0.028<0.040? Low energy CNGS
<0.033<0.039<0.056CNGSx1.5*
<0.039<0.047<0.067CNGS*
<0.042<0.049<0.06<0.085MINOS
<0.14<0.14<0.14<0.14<0.14<0.14CHOOZ200920082007200620052004
P. MigliozziIndication of time-line
Simone Gilardoni24 Aprile 2003 DPNC
The BETA-BEAM
1. Produce a Radioactive Ion with a short beta-decay lifetime
2. Accelerate the ion in a conventional way (PS) to “high” energy
3. Store the ion in a decay ring with straight sections.
4. It will decay. νe (νe) will be produced.
- SINGLE flavour - Known spectrum- Known intensity- Focussed- Low energy- “Better” Beam of νe (νe)
The “quality factor” QF=Γ/E0 is bigger than in a conventional neutrino factory. In addition, ion production and collection is easier. Then, 500000X more time to accelerate.
Muons:Γ~500E0~34 MeVQF~15
6He Beta-:Γ~150E0~1.9 MeVQF~7918Ne Beta+:Γ~250E0~1.86 MeVQF~135
Simone Gilardoni24 Aprile 2003 DPNC
The Acceleration principle
ISOL Targetand ECR Linac Cyclotron Storage Ring
PS SPS
2500 m
R=300 m
Decay ring/Buncher
Bunch rotation is the crucial issue for atmospheric background control!
Studies are made on EXISTING CERNmachines. Why? Much more detailedknowledge exists, the best way to identifypossible problems and limitations.
Simone Gilardoni24 Aprile 2003 DPNC
channel at neutrino factory
High energy neutrinos at NuFact allow observation of νe→ντ(wrong sign muons with missing energy and P⊥). UNIQUE
Liquid Argon or OPERA-like detector at 3000 km.
Since the sinδ dependence has opposite sign with the wrong sign muons, this solves ambiguitiesthat will invariably appear if only wrong sign muons are used.
ambiguities with only wrong sign muons (3500 km)
equal event number curvesmuon vs taus
associating taus to muons(no efficencies, but only OPERA mass)
studies on-going
A. Donini et al
Simone Gilardoni24 Aprile 2003 DPNC
Why so far?
0.00E+00
5.00E-03
1.00E-02
1.50E-02
2.00E-02
2.50E-02
0 5000 10000 15000Distance L (km)
Vac.
Osc
ill. P
rob.
E = 1GeVE = 30 GeV
Earth diameter:Vertical storage ring?
Simone Gilardoni24 Aprile 2003 DPNC
Degeneracies
Degeneracy: 2 or more parameter sets fit the same data
Three types, all of which can effect measurement of δ & θ13:
( ) ( )1313 ',', θδθδ ↔
223
223 mm ∆−↔∆
4,
2 232323πθθπθ ≠−↔
θ13=8o, δ=-90o, 0o, 90o, 180o
(1)
(2)
(3)
( ) ( )δθδθµµ νννν ,',' 1313 ee
PP =
( ) ( )δθδθµµ νννν ,',' 1313 ee
PP =
(1) ⇒
Simone Gilardoni24 Aprile 2003 DPNC
Degeneracies
∆
∆+≈
−≈
ELm
ELm
44cot2sincotcos'
,'212
213
12231313 θθδθθ
δπδθ13
large
NB depends on L/E ⇒ possible solutions
• Two baselines and E-dependence at NF
• NF + SB combination
• Two off-axis detectors
• νe→ντ as well as νe→νµ
Mena
Huber/Mena
Whisnant
Meloni
Simone Gilardoni24 Aprile 2003 DPNC
Degeneracies
Mena
NuFact at 2810km
+ SB at
130KM
NuFact at 732km
+ SB at
130KM
large
small
Simone Gilardoni24 Aprile 2003 DPNC
νe appearance in JHF-Kamioka (phase 1)
µ eπ0
1.8 events 9.3 events 11.1 events
123.2 events @ sin22θ13=0.1, ∆m2=3×10-3eV2
Backgrounds
Signal
(5 years running)
Simone Gilardoni24 Aprile 2003 DPNC
Europe: SPL FrejusGen
eve
Italy
130km
40kt400kt
CERN
SPL @ CERN2.2GeV, 50Hz, 2.3x1014p/pulse
4MWNow under R&D phase
Simone Gilardoni24 Aprile 2003 DPNC
SPL neutrino beam
Simone Gilardoni24 Aprile 2003 DPNC
CP δ and θ13
40 kt Detector 400 kt Detector
Running time:
• 10 y antineutrinos
• 2 y neutrinos