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Simone Gilardoni 24 Aprile 2003 DPNC
Introduction to the Neutrino Factory
Simone Gilardoni
DPNC - Université de Genève
CERN - AB/ABP Division
Simone Gilardoni 24 Aprile 2003 DPNC
Neutrino oscillation
Observation: into another of different flavour
Results: NEUTRINOS HAVE MASSMASS STATES FLAVOUR STATESParameters:
• 3 masses– Two m2 differences
• Three mixing angles• One delta phase
3
2
1
1212
1212
1313
1313
2323
2323
100
0
0
0
010
0
0
0
001
ν
ν
ν
ν
ν
ν
δ
δ
τ
μ cs
sc
ces
esc
cs
sci
ie
Simone Gilardoni 24 Aprile 2003 DPNC
Neutrino Oscillations
ii
iU Mixing described by
For 3-flavour eigenstates U is Maki-Nakagawa-Sakata (MNS):
231312231312231223131223
231312231312231223131223
1312131213
ccescscseccsss
scesssccecsssc
essccc
Uii
ii
i
6 parameters: 3 mixing angles - θ23,θ12 and θ13
CP-violation angle - δ
2 mass differences - Δm223 and Δm2
12
Transition probability:
E
LmP e 4
sinsin2sin2232
232
132
Simone Gilardoni 24 Aprile 2003 DPNC
Three family oscillation
3
2
1
1212
1212
1313
1313
2323
2323
100
0
0
0
010
0
0
0
001
cs
sc
ces
esc
cs
sci
ie
Atmospheric Neutrinos
SolarNeutrinos Phase CP
• Super-K atm.
• P( )
• Maximal mixing
• m2 3 10-3 eV2
• L/E = 1 GeV/500 km
• SNO
• P(e x)
• Large Mixing (LMA)
• Kamland
•L/E MeV/1.5 1011m
• Limit from CHOOZ
• Goal of next generation of neutrino-beam
•If 13 is zero, IMPOSSIBLE to observe CP violation
Simone Gilardoni 24 Aprile 2003 DPNC
Two friends for Nufact
SNO: D2O detector
Non-e flux in solar neutrinos
Kamland: e disappearance from Nuclear Reactor
LMA solution for solar neutrinos
Simone Gilardoni 24 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 Gilardoni 24 Aprile 2003 DPNC
Road Map
• Experiments to look for 13
– Look for e in beam (ICARUS, MINOS)– Off-axis beam (JHF-SK, off axis NUMI)– Low energy SuperBeams
• Experiments to look for CP/T violation or for 13 (if too small)
– Beta-beams (combined with SuperBeam)
– Neutrino Factory
eeFNeeeLiHe 181866
ee
Simone Gilardoni 24 Aprile 2003 DPNC
JHF ready in 2007
Construction2001 ~ 2006 (approved)
JAERI@Tokai-mura(60km N.E. of KEK)
(0.77MW)
Super Conductingmagnet for beam line
Near detectors@280m and@~2km
1021POT(130day)≡ “1 year”
Simone Gilardoni 24 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 Gilardoni 24 Aprile 2003 DPNC
Nufact FAQ
• Why neutrinos from stored muons:– Pure , e 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 Gilardoni 24 Aprile 2003 DPNC
Beam Composition
Nufact Beam WANF Beam
The scales are different !
Simone Gilardoni 24 Aprile 2003 DPNC
Energy and flux specs
NuFact near detector
1020 decay/year4.0 106 CC evt. 1.7 106 CC evt.
per kg-year
Minos near detector
3.7 1020 pot/year 2.5 106 CC evt.0.6 106 CC evt.
per ton-year
Physics at far detector
Simone Gilardoni 24 Aprile 2003 DPNC
The Holy Grail: any leptonic CP violation?
CP is observable IF:
• sin212 and m212 are large (LMA) and
sin213 small (but not too small…)
• Appearance experiment: P(e) – P(ee) is T invariant CP is conserved
(CP not observable from solar or reactor neutrinos)
termsSolar
ELmA
PP
PPCP
ee
ee
13
12212
sin
sin)4/sin(sin
)()(
)()(
Simone Gilardoni 24 Aprile 2003 DPNC
• Measure 13 via P(e) 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 P(e) P(e)
Need of high energy e:
ee+
Physics at a Nufact
Simone Gilardoni 24 Aprile 2003 DPNC
+ e++ +e
+Oscillation
Wrong Sign muons
1016p/s
3 1020 eyr
3 1020 yr
0.9 1021 yr
Simone Gilardoni 24 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 Gilardoni 24 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 Gilardoni 24 Aprile 2003 DPNC
Proposed site
Old ISR tunnel, site of accumulator + bunch compressorRadius = 50 m
Simone Gilardoni 24 Aprile 2003 DPNC
Target Nufact• Target:
– Mercury: Z = 80 short target Liquid 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 Gilardoni 24 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 Gilardoni 24 Aprile 2003 DPNC
Jet test a BNL E-951Event #11 25th April 2001
P-bunch: 2.71012 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 Gilardoni 24 Aprile 2003 DPNC
The Harp experiment Hadron production cross section measurement
Simone Gilardoni 24 Aprile 2003 DPNC
Magnetic horn
Protons
Current of 300 kA
To decay channel
Hg Target B1/R
B = 0
Simone Gilardoni 24 Aprile 2003 DPNC
Time (arb.)
Decay channel
Ene
rgy
(GeV
)
Solenoid B=1.8 T, L=30 m “Life Time” 18 m @ p=400 MeV/cGeometry
Energy spread reduction needed
• Huge Energy spread– Huge velocity spread
– LEP E/E 10-3
– NF E/E 2
• Debunching• Beam type
– – E-t correlation
30 m
Simone Gilardoni 24 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 Gilardoni 24 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 Gilardoni 24 Aprile 2003 DPNC
Cooling: the problem(transverse phase space)
Accelerato
Accelerator acceptance R 10 cm, x’ 0.05 rad rescaled @ 200 MeV
and after focusing
• Problem: Beam pipe radius of storage ring P or x’ and x reduction needed: COOLING
Simone Gilardoni 24 Aprile 2003 DPNC
Ionization Cooling : the principle
H2 rf
Liquid H2: dE/dx
RF restores only P//: E constant
Beam
sol
sol
Simone Gilardoni 24 Aprile 2003 DPNC
2) Focusing :
a) Needed when x’ reduction comparable with multiple scattering b) same rotation center for the spiral motion. (Rematching)
Cooling : the channel
1) Cooling I : x’ reduction 3) Cooling II : x’ reduction
0i
f
E
E'-' if xx
Heating term
‘
0
6.130 X
xpcMeV
H2 has X0= 8.9 m
Cooling works best with high x’
Simone Gilardoni 24 Aprile 2003 DPNC
Cooling: the results
Results: phase space density increased by 16 (Cooling rate for MICE: 16%)
IN
OUT
Simone Gilardoni 24 Aprile 2003 DPNC
MICE: Muon Ionisation Cooling Experiment
Proposal to be submitted to RAL before end of the year
Simone Gilardoni 24 Aprile 2003 DPNC
Accelerator and Particle physics together
TPG TrackerSciFi Tracker
Example of cooling
Simone Gilardoni 24 Aprile 2003 DPNC
Mice roadmap (at RAL?)
- STEP I: 2004
STEP II: summer 2005
STEP III: winter 2006
STEP IV: spring 2006
STEP V: fall 2006
STEP VI: 2007
Simone Gilardoni 24 Aprile 2003 DPNC
Storage ring
• Two straight sections pointing to two detectors
• Two possible shapes– triangle– bow tie
• Lattice design for beam divergencex’
beam divergence dominated by decay =m/p= 2mrad (@ 50 GeV)
25% useful decays per direction
Simone Gilardoni 24 Aprile 2003 DPNC
Technical problems
14
Could you imagine a screw driver falling down from here?
Simone Gilardoni 24 Aprile 2003 DPNC
Around Europe...
• First possible location: Gran Sasso 732 km
• Second location: 3500 km away bestCandidates: Svalbards (Norway)
Gran Canaria (Spain)
Simone Gilardoni 24 Aprile 2003 DPNC
Why two locations?
From P. Hernandez
•Fit of 13 and a the same time
•No sensitivity at 732 km
•Better to combine with 2810 km
Simone Gilardoni 24 Aprile 2003 DPNC
But not too far: no CP sensitivity
L = 7332 km
From P. Hernandez
Simone Gilardoni 24 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
CC e CC signalEvents for 1 year
Simone Gilardoni 24 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
= 90 deg99%C.L. Curves
(M. Mezzetto, NNN02)
Simone Gilardoni 24 Aprile 2003 DPNC
Last question: about financing?
• For the time being our situation is not so good….
BUT….. Some ideas are developing…
Simone Gilardoni 24 Aprile 2003 DPNC
SNO detector
• 1000 ton of D20
• 12 m diam. • 9456 PMTs
• Aim: measuring non e neutrinos in a pure solar e beam
• How? Three possible neutrino reaction in heavy water:
Simone Gilardoni 24 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 Gilardoni 24 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 Gilardoni 24 Aprile 2003 DPNC
sin2213
* Designed for 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<0.14CHOOZ
200920082007200620052004
P. MigliozziIndication of time-line
Simone Gilardoni 24 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. e (e) will be produced.
- SINGLE flavour - Known spectrum- Known intensity- Focussed- Low energy- “Better” Beam of e (e)
The “quality factor” QF=/E0 is bigger than in a conventional neutrino
factory. In addition, ion production and collection is easier. Then, 500000X more time to accelerate.
Muons:~500E0~34 MeVQF~15
6He Beta-:~150E0~1.9 MeVQF~7918Ne Beta+:~250E0~1.86 MeVQF~135
Simone Gilardoni 24 Aprile 2003 DPNC
The Acceleration principle
ISOL Target and 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 Gilardoni 24 Aprile 2003 DPNC
channel at neutrino factory
High energy neutrinos at NuFact allow observation of e(wrong sign muons with missing energy and P). UNIQUE
Liquid Argon or OPERA-like detector at 3000 km.
Since the sin 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 Gilardoni 24 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 15000
Distance L (km)
Vac
. Osc
ill. P
rob
.
E = 1GeV
E = 30 GeV
Earth diameter:Vertical storage ring?
Simone Gilardoni 24 Aprile 2003 DPNC
Degeneracies
Degeneracy: 2 or more parameter sets fit the same data
Three types, all of which can effect measurement of & 13:
1313 ',',
223
223 mm
4,
2 232323
13=8o, =-90o, 0o, 90o, 180o
(1)
(2)
(3)
,',' 1313 ee
PP
,',' 1313 ee
PP
(1)
Simone Gilardoni 24 Aprile 2003 DPNC
Degeneracies
E
Lm
E
Lm
44cot2sincotcos'
,'212
213
12231313
13
large
NB depends on L/E possible solutions
• Two baselines and E-dependence at NF
• NF + SB combination
• Two off-axis detectors
• e as well as e
Mena
Huber/Mena
Whisnant
Meloni
Simone Gilardoni 24 Aprile 2003 DPNC
Degeneracies
Mena
NuFact at 2810km + SB at 130KM
NuFact at 732km + SB at 130KM
large
small
Simone Gilardoni 24 Aprile 2003 DPNC
e appearance in JHF-Kamioka (phase 1)
e0
1.8 events 9.3 events 11.1 events
123.2 events @ sin2213=0.1, m2=3×10-3eV2
Backgrounds
Signal
(5 years running)
Simone Gilardoni 24 Aprile 2003 DPNC
Europe: SPLFrejusG
enev
e
Italy
130km
40kt400kt
CERN
SPL @ CERN2.2GeV, 50Hz, 2.3x1014p/pulse 4MWNow under R&D phase