neutrino oscillations at t2k
TRANSCRIPT
Neutrino oscillations at T2K
H.KakunoUniversity of Tokyo
Neutrino Oscillation Workshop 2008Conca Specchiulla, Italy, September 9, 2008
Primary goal of the T2K
...4sin2sin4
4sinsin2sin)(
3122
212
3122
232
132
ELmELmJ
ELmP
r
e
Search for the e appearance: e
Precise measurement of the disappearance:
P( )≈1-sin223sin2(m223L/4E))
Goal : (sin22)~0.01, (m2) <1×10-4 [eV2]
Expected Sensitivity for sin22→down to ~0.01
100
0cossin
0sincos
cos0sin
010
sin0cos
cossin0
sincos0
001
1212
1212
1313
1313
2323
2323
CP
CP
i
i
e
e
T2K experiment
280m, (& 2km)2
Pure beam
750kWCompleted Experiment
Under Construction
- Next generation long-baseline neutrino oscillation experiment- Intense beam is generated by new J-PARC facility
Neutrino beam
OA3°
OA0°
OA2°OA2.5°
energy spectrum (flux × Cross Section)C
Oscillation Prob.@ L=295kmm2=2.5×10-3, 3.010-3[eV2]
( )
Pseudo-Monochromatic beam by Off-Axis method (ref. BNL E899)b
- Off-Axis angle: set to 2.5 degree
p
120m120m0m0m 280m280m 2 km2 km 295 km295 km
on-axison-axis
off-axisoff-axis
2.52.5oo
Super-KSuper-K
-mon-mon
Under discussion
J-PARC accelerator
``
Neutrinobeamline
Neutrino beam
28th Jan. 2008
Linac:Beam commissioning is started in Nov 2006
3GeV RCS:Beam commissioning is started in Sep. 2007
Main Ring(MR):Beam commissioning is started in May 2008,Closed orbit has been establishedAcceleration (30GeV) will be started in Dec. 2008
Commissioning of the neutrino beam-line will be started from Apr 2009
Primary beam lineProton beam line from the Main Ring to the target
Preparation Section
Arc Section
• 28 superconducting magnets.
• Combined function: D:2.6T, Q:18.6T/m
• 1W/m lossFinal Focus Section
• 10 Normal Conducting magnets• (2 Dipole, 4 Quad, 4 Str)• 250W loss
• 12 Normal Conducting magnets
• (2 Dipole, 5 Quad, 5 Str)• 750W loss
Primary beam-line: monitors
Position : Electro-static monitor (ESM) Profile : Segmented Secondary Emission Monitor (SSEM)E : Optical transition Radiation monitor (OTR) in front of the target Intensity : CT (Current Transformer) Loss monitors (BLM): Ion. Chamber
ESM SSEMCryogenic test
OTR
Installation
Monitor center of the beam < 0.5mm and profile(size) of the beam < 0.7mm to protect the target and to maximize the neutrino flux
Secondary beam-line
Target Stationtarget & horn system
Decay VolumeBeam Dump /Muon Pit
- Beam dump 94 graphite blocks
- Muon monitor: Semiconductor array + Ionization chamber
Helium vesselHelium vesselof target station
Decay volume
Beamdump
Muonpit
Secondary beam-line: Target&HornTarget (Graphite)T 26mm(D)x900mm(L)2 Thermal shock @30GeV-750kW:
~ 7MPa (<Tensile strength 27MPa)~ Forced flow Helium gas cooling
736oC
30GeV-750kW
320kA
3rd Horn1st Horn
320kA operationachieved
Full scalemockup test
Horn system Three horn system I=320kA, B=2.1T(max)I• Full scale mock-up of the 3rd horn
-@320kA operation achieved
Long term endurance test
1st and 3rd horns→done, 2nd horn→ongoing
Secondary beam-line:Beam dump&Muon monitor
10m 4m
Helium VesselHelium Vessel
OA 2.5OA 2.5oo
Hadron absorber assembly is completed Installation on October
• Muon monitor:• Spill –by-spill
monitor the muon beam profile center < 3 cm
• Beam intensity measurement accuracy: 3%
• Installation by end 2008
Ionization chamber s
Si PINDiodes
ND280: facilityN
Current design37m
2.5deg beam center28.5m
Ground level
Off-Axis Neutrino Detector
(Monitor at SK direction)d
INGRID:On-Axis Neutrino Monitor(Monitor at beam direction)d
ND280: On axis detector (INGRID)N Measure -beam profile
-beam direction at 1mrad precision.
iron - scintillator stacks x 16units 7 horizontal , 7 vertical , 2 off-diagonal
INGRID will be ready for beam commissioning: Apr. 1st, 2009.
construction of modules
ND280: Off axis detector Off-axis detector: In Magnetic field
(B=0.2T)( Measure -flux in SK direction :
ND(E). Measure , and e+e fluxes separately. Neutrino Energy CC-QE kinematics.
Cross sections of interactions CC-1CC-QE … BG for E
reconstruction NC-0 production … BG for e detection
Reuse the UA1 magnet (it have been installed) Off-axis detector will be installed in
summer 2009 except for some parts of ECAL. It become ready for physics run from 2009 fall.
SMRD
Installed yoke
Far detector: Super Kamiokande50kt Water Cherenkov detector 20”PMT x 10,000 +Anti counter x 2000SK reconstruction iscompleted in Apr. 2006→Back to 40% Photo coverage.Start full operation in July 2006 (SK-III)22
DAQ-upgrade is ongoingTo be completed by mid September~6 month commissioning before T2K experiment(SK-IV)(
Possible MR Power Improvement ScenarioKEK ROADMAP
Day1(up to Jul.2010)2
Next Step KEK ROADMAP Ultimate
Power(MW)P 0.1 0.45 1.66 ?
Energy(GeV)E 30 30 30
Rep Cycle(sec)R 3.5 3-2 1.92
No. of Bunch 6 8 8Particle/Bunch 1.2×1013 <4.1×1013 8.3×1013
Particle/Ring 7.2×1013 <3.3×1014 6.7×1014
LINAC(MeV)L 181 181 400
RCS h=2 h=2 or 1 h=1
After 2010, plan depends on financial situationGoal at initial stage: T2K Physics run with 100kW beam × 107 sec by 2010 summer.
“We request total integrated beam power larger than 0.75MW × 15000h (15000 h = 5yrs ×3000h) at any proton energies between 30 and 50 GeV.”
Physics sensitivity e appearance
T2K 90%CL sensitivity sin2223 = 1.0 is assumed.~ 5 years @ full intensity(750kW)~
Stat. error+ Syst. error for BG subtraction (10%)+
(OA2.5(OA2.5°° ))))
~0.01 @ m213=2.510-3[ev2], =0
sin2213 = 0.1# of events in 0.35~0.85 [GeV] Signal … 103 Beam e BG … 13 BG from … 10
Physics sensitivity (cont'd)P disappearance : P( )=1-sin223sin2(1.27 m2
23L/E)) Goal : (sin22)~0.01, (m2
) <1×10-4 [eV2]
K2K … hep-ex/0606032SK… Phys. Rev. Lett. 93,101801(2004),MINOS... hep-ex/0806.2237M
(OA2.5(OA2.5°° ))))
2.5
2.6
2.7
2.8
2.9
m2 [
10-3 e
V2 ]
--68%CL--90%CL--99%CL
K2K & SK &MINOS
~ 5years @ full Intensity
MC
Statistics ×50
Stat. Error only
Hadron Production measurement at CERN SPS (NA61 experiment)C
obsNDNFSK R /
exp
Neutrino flux is estimated from the flux at the near detector
To estimate the error of Far/Near ratio:
Error from F/N ratio
1
1%
10%
T2K goal
0.15(m232)[10-4eV2]
0.5%(sin2223))
<4%(Nbg) for e app.
w/ NA61
Measure the hadron production for30-50GeV protons on thin and thick carbon target at NA61
Detector Existing at CERN SPS 2ndary beam line Used by NA49 (Heavy ion)U
Beam First data taking in Oct. 2007 and more data in 2008
Uncertainty from the Hadron production model can be
controlled
-cp
=0-
cp=90
-cp
=270
E/L
Osc
illat
ion
pro
b.
Future If sin22 is measured at T2K and is found large ( > ~0.01),
CP-violation study is possible
Strategy
- Measure 1st and 2nd maximum of oscillation w/ different E/L and/or
- Measure with both and beams
-Neutrino oscillation w/ different E/L will provide information of
cp
-Oscillation prob. is different between neutrino and anti-neutrino→cp→ -cp)
wheree
atmospheric
Interference
solar
CPV
1st oscillation maximum
2nd oscillation maximum
Future(cont’d)F
Okinoshima
KamiokaKorea
Various scenarios(upgrade of the far detector) are proposed:
See slides of NP08: http://j-parc.jp/NP08
Hyper Kamiokande
Liquid Ar TPC
Summary T2K is a Long Baseline experiment w/ high intensity beam by JPARC accelerator Beam line construction is on schedule - Although very tight
- Almost all beam line components will be installed in FY2008 Beam commissioning will start Apr. 2009 Off-axis detector will be ready by 2009 fall run - except for a part of ECAL We aim to obtain 1st physics result from 100kW107sec beam operation by 2010 summer.
Search for e & 13 measurement.
Precise measurement of 23 & m223 via disappearance.
- If e is observed and is found large, - look for CPV. -Various upgrade options are under study
Introduction
3
2
1
1212
1212
1313
1313
2323
2323
100
0cossin
0sincos
cos0sin
010
sin0cos
cossin0
sincos0
001
i
ie
e
e
mixing matrix: 1312, 23
SK Atmospheric+Long BL(K2K, MINOS)+
Solar, KamLANDLong BL
13
, : Unknown
Is 23
=/4?Is
13 non-zero?
CP-violation?
Commissioning schedule
DRY RUNDRY RUN
Install Septum Magnets
[CONSTRUCTIONCONSTRUCTION] [INSTALATION][INSTALATION] [COMMISSIONING][COMMISSIONING]
1st STAGE: Establish
Closed Orbit
Inspect PPS Rad.shield (12/25)R
Install Fx Kickers& Sx devices
2nd STAGE: Acceleration
(30GeV)(
3rd STAGE: Fast
Extraction
☼☼☼☼
☼☼High Intensity
Run
☼☼ ☼☼☼☼
NOW
1st stage of the MR beam commissioning is successfulCommissioning of the neutrino beam will start from Apr. 2009High intensity beam with six bunches from Sep. 2009
Now preparing neutrino beam-line components toward the neutrino beam commissioning
Error from F/N ratio
1
1%
10%
T2K goal
0.150.5~1(m232)[10-4eV2]
0.5%1.5~3%(sin2223))
<4%15%(Nbg) for e app.
w/ NA61If R~20%
Assumed Systematic ErrorsAssumed Systematic Errors
Normalizationnon-QE/QE ratio
Energy scale
5%
5%
1%
0.010.01 1×101×10-4-4eVeV22
• Errors will be reduced byErrors will be reduced by near detector and near detector and pion production pion production measurementsmeasurements
(sin(sin22 2 2)) ((mm22))
Spectrum Shape 20%
Beam Width 5%
Sta
tistic
alE
rro
r
OA2.5OA2.5oo
5510102121 POT POT
Sta
tistic
alE
rror
Systematic error
Sta
t.
Sta
t.
Primary beam-line: Magnets Superconducting combined function magnets D:2.6T, Q:18.6T/m
All the magnets are installed
Evacuation and cooling starts in Autumn
Normal-conducting magnets All the magnets are installed
Dipole Quad SteerPrep Sect 2(H) 5 3(H)+2(V)
FF Sect 2(V) 4 2(H)+2(V)Combined(Dipile+Quad)
ARC Sect 14 “doublets”
Transport to tunnelTransport to tunnelFeb.8, 2008Feb.8, 2008
~11m
J-PARC milestone
Hardware upgrade is necessary for 1MW.
0.75 MW
Goal at initial stage: T2K Physics run with 100kW beam × 107 sec by 2010 summer.
“We request total integrated beam power larger than 0.75MW × 15000h at any proton energies between 30 and 50 GeV.”
15000 h = 5×3000h ≒5×107sec
-cp
=0-
cp=90
-cp
=270
E/L
Osc
illat
ion
pro
b.
Future
Upgrade of the proton beam power: 0.75MW->1.66MW
Upgrade Far detector e.g. Hyper Kamiokande (~1Mt)H
If sin22 measured @ T2K > 0.01, CP-violation study is possible
Strategy:
Neutrino oscillation w/ different E/L will provide information of
cp
See slides of NP08:http://j-parc.jp/NP08/