recent results from neutrino experiments and plans for the neutrino super beam in japan
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Recent Results from Neutrino Experiments and Plans for the Neutrino Super Beam in Japan
Discovery of neutrino oscillations finite neutrino masses (2 and 3) (1998 – present)Small as expected
Mixing among neutrino flavors expectedQuark mixing implies small mixing
Y.Totsuka, KEKNSS-2003, 031021
2
e
( ) =
1
2
3
( )Ue1
U1
U1
( Ue2
U2
U2
Ue3
U3
U3
)
c12c13 s12c13 s13e-i
-s12c23-c12s13s23e-i c12c23-s12s13s23e-i c13s23
s12s23-c12s13c23e-i -c12s23-s12s13c23e-i c13s23
U (Maki-Nakagawa-Sakata Matrix) =
sij=sinij, cij=cosij, =CP
Mixing matrix
( )
Free moving states(mass eigenstates)
Interacting states
Discovery of large mixing angles, 23 and 12
3
p, HeAtmosphere
Atmospheric neutrinos - I
e
Earth
Super-K
±
±
e±
Expected event rate is uncertain by ~15% : e = 2 : 1 (low energy) known better than 5% Up-down symmetry for E > 1 GeV
4
40m
41.4m
Super-Kamiokande (1996)
1996-50000ton water11146 50cm PMT (40% photo coverage)1000m undergroundMin det. energy ~ 5 MeVBasic reactions
+ N + Xe + N e + X
5
SK-II Cosmic ray muon sample
20inch PMT with Acrylic + FRP vessel
Super-Kamiokande II Accident on Nov 12, 2001 Repaired and restarted in Dec, 2002 Inner detector with ~5200 20” PMTs Outer detector with 1885 8” PMTs
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2=170.8/170 d.o.f. at (sin2223, m232)=(1.00, 2.0x10-3eV2)
2=445.2/172 d.o.f. (null oscillation)
1489 day FC+PC data + 1646 day upward going muon data
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Allowed region of the oscillation parameters
Assuming oscillation
Best fit 2
min = 170.8/170 d.o.fat (sin2223 m23
2) = (1.0, 2.0 x 10-3 eV2)
90% CL allowed regionsin2223> 0.91.3x10-3 < m23
2 <3.0x10-3 (eV2)
Assuming null oscillation 2 = 445.2/172 d.o.f
(complete SK-I dataset)
Soudan-2
MACRO
Super-K68% CL90% CL99% CL
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K2K
250km
Long baseline neutrino oscillation experiment
12 GeV PS at KEKNeutrino beamline
<E> ~ 1.3GeV
98% purityBeam monitors and nea
r detectorbeam direction measurement flux and spectrum
Far detector flux and spectrum
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Best fit 1R spectrum & Nsk
Best fit point (sin2223 , m232) =
(1.0, 2.8x10-3eV2) KS test prob.(shape): 79% NSK=54 (Obs.=56)
Very good agreement in shape & NSK with atmospheric neutrinos
Expected w/o oscillationNormalized w/o oscillationNormalized with best fit oscillation
Total number of obs. Events: 56 16 (Jan03-Apr03)
Expected w/o oscillation: 80.6 +7.3-8.0 24 +2.3-2.1
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Comparison with SK atm observation
K2K(1R shape+NSK) SK (FC+PC+up)
90%CL
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Solar image
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SNO: e e (ES); ed epp (CC); d pn, Cl(n,)Cl, (NC)
Electronics hut Control room
1000
to
n h
eavy
wat
er
(12m
ac
rylic
ves
sel)
9456 of 8 inch PMTs
INCO’s Creighnton mineSudbury, ON, Canada
2km
SNO
1700+5300 ton light water(17.8m stainless steel support, 34mh x 22m barrel-shaped cavity)
(6010mwe)
photo coverage 55% (R<7m) cosmic ray muons ~70 events/day fiducial volume 0.7kt (R,5.5m) Trigger rate (data) 6~8Hz
(~2MeV threshold) Trigger efficiency 100%@~3MeV From compton e- from 16N source (~5 MeV)
vertex resolution 16cm energy resolution 16% angular resolution 27℃
NaCl in D2O
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CC = e
ES = e +0.154 ,
NC = e + ,
SNO CC = 1.7+-0.05+-0.09 ES = 2.39 +-0.12 NC = 5.09
SK ES = 2.32+-0.03
Evidence for an active non-e component !
[x106/cm2/s]
Super-K + SNO combined (as of 2002)
+0.24- 0.23+0.44 +0.46- 0.43 - 0.43
+0.08- 0.07
SKES
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SNO rates and day/night spectra and Super-K zenith spectra
e oscillation
-3
-4
-5
-6
-7
-8
-9
-10
-11
log
m
2 (e
V2 )
-4 -3 -2 -1 0 1
Log tan2
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Kam-LAND
1000m3 liquid scintillator3000m3 oil+water shield1300 17-inch PMTs + 600 20-inch PMTsAnti-e from reactors (L~170km)Detect e+ from e + p e+ + n (Eth = 1.8 MeV)Observation started on 22 Jan 2002
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Kam-LAND result
145.1 live days, 162 ton year exposure Te > 2.6 MeV, 86.8+-5.6 ev expected 56 ev observed with 1 BG estimated
Te > 0.9MeV124.8+-7.5 ev expected86 ev observed with 2.9 +-1.1BG estimated
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KamLAND confirms the LMA solution!
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FIG. 5: Global neutrino oscillation contours. (a) Solar global: D2O day and night spectra, salt CC, NC, ES fluxes, SK, Cl, Ga. The best-fit point is m2 = 6.5 × 10-5, tan2 = 0.40, fB = 1.04, with 2/d.o.f.=70.2/81. (b) Solar global + KamLAND. The best-fit point is m2 = 7.1 × 10-5, tan2 = 0.41, fB = 1.02. In both (a) and (b) the 8B flux is free and the hep flux is fixed. fB = 8B flux measured / SSM.
Nucl-ex/0309004v1 6Sep2003
SNO
19
ντ
νe νμ
31?
CP?
Atm
ospheric neutrinos
Solar neutrinos
K2K
neutrinosm
23 2 = 1.3 - 3.0×10-3 eV
2
sin22
23 = 0.9 – 1.0
m122 = 6 - 9×10-5 eV2
sin2212 = 0.7 – 0.9
KamLAND
What to do next
Measure 31 and m31
2 (~ m232)
m12
2, m232, 12, 23 precisely
Quarks:sin2212 = 0.188 +-0.007sin2223 = 0.0064+-0.0010
20
e , electron appearance
P(e) = 4c132s13
2s232 sin2(m31
2L/4E)(1 + 2a(1-2s132)/m31
2)
+ 8c132s12s13s23(c12c23 cos – s12s13s23)
×cos(m232L/4E) sin(m31
2L/4E) sin(m212L/4E)
- 8c132c12c23s12s13s23 sin
×sin(m232L/4E) sin(m31
2L/4E) sin(m212L/4E)
+ 4s122c13
2(c122c23
2 + s122s23
2s132
- 2c12c23s12s23s13 cos) sin2(m212L/4E)
-8c132s13
2s232(1 – 2s13
2)(aL/4E)
×cos(m232L/4E) sin(m31
2L/4E) ,
where a [eV2] = 2√2GFneE = 7.6×10-5 [g/cm3] E [GeV] , red terms change sign for anti-neutrinosP( e) – P( e)
P( e) + P( e)~ m12
2L 4E
sin212
sin13
sinACP =
21
Strategy and Sensitivity Goal (Phase I)
~ 5 yearsPrecisely measure 23 and m23
2. e appearance search
Sensitivity goalssin2223 ~ 0.01m23
2 < 1x10-4 eV2
sin2213 ~ 0.006 (90% CL)
Study neutrino interactions at the near detector
22
T2K (Tokai-to-Kamioka)
J-PARCHyper-Kamiokande
23
J-PARC
Joint Project by KEK and JAERI 3 GeV RCS: spallation-neutron and muon sources
Life and material sciences 50 GeV MR: slow and fast extracted protons
Kaon physics Neutrino physics (long baseline oscillations)
LINAC: intense proton source ADS
(180 MeV,
24
25
injection energy 400 MeV ( 180 MeV ) extraction energy 3 GeV harmonic number 2 repetition rate 25 Hz # of protons / pulse 0.83 E14 average beam current 333μA beam power 1 MW
3 GeV RCS
Magnetic alloy cavity
26
50 GeV MR
Beam energy: 50 GeV (40 at phase 1)
1 cycle: 3.53s 8 bunches in 9RF buckets Bunch spacing: 598ns Spill width ~ 5s Bunch length ~ 36ns (±3
) 6ns (1
# of protons: 3.3×1014 ppp
Beam current: 15A (slow extraction)
Rf frequency: 1.68 (inj.) – 1.73 (ext.) MHz
flux* at SK = 1.9×107 / cm2yr(1yr = 1021 pot: 123 days at .75MW)
*2.5°Off Axis, 130m decay pipe
3.53s
1.9s
fast
Injection : 0.17sacceleration : 1.96sextraction : 0.7 scurrent down : 0.7 stotal: : 3.53s
slow
0.17
1.96 0.7
0.7
27
600MeV Linac
3GeV PS
50GeV PS
N
Near Detector (280m)Neutrino Beam Line
To Super-Kamiokande(295km away)
Neutrino beam line
Construction2001 ~ 2007
JHF MINOS K2K
E(GeV) 50 120 12
Int.(1012ppp) 330 40 6
Rate(Hz) 0.3 0.53 0.45
Power(MW) 0.75 0.41 0.0052
JAERI@Tokai-mura(60km N.E. of KEK)
(Approval in Dec.2000)
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Off Axis Beam
WBB with a misaligned beam line from the det. axis High intensity at low energy: 4500 int./22.5kt/yr Contamination e: 0.8%(0.2% @ peak)
Decay Kinematics
E (GeV)
E
(Ge
V)
0 0.4 0.8 1.2 1.6 2 E (GeV)
2x10-3eV2, L = 295km
p
140m0m 280m 2 km 295 km
on-axis
off-axis
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Fast extraction section
neutrino beamline
30FQ
1F
H1
R104433
R107700R106400
R100400R99600
Arc Sectionco
mbi
ned
func
tion
SC m
agne
ts
ORDipole
Quadrupole Combined
31
Focusing Section
solid graphite, 30mm in diam, 900mm long
Target station
32
100 cm100 cm90
0
472
2500
1400
2000
809
Horn system
I=~300kA, three short horns Need to tolerate big heat load from radiation Stress analysis is in progress
Carbon target
33
空隙(サービスエリア)
TP+11.8m(0.244Sv/h)
土盛り
TP-1.1m TP-1.1m
0.07Sv/h for 1W/m line
(ターゲット・ステーション 地下レベル)
断面図
FQ3AFH2 FQ3B FQ4 FV1 FV2
放射化物保管室
1.40
TS上屋
2.11
3NBT (TP+8m)レベル
3NBT
コンクリート
コンクリート
土盛り
コンクリート
コンクリート
μ ピット機械室( )半地下
汚染検査室
FL=TP-14.3
遮蔽ブロック
Side View
Top view
4MW beam can be accepted.
max.120o
(half year continuous operation)
(Temperature is controllable under 100o by intermittent operation)
Decay Volume
Water cooling pipe
50o
14o
~3.5deg
130m from target
To Super-K~1.3deg
34
Near detector at 2km from the target
9.2m
16.2m
8m
4m
Total mass : 1077ton
Fid. Mass : 100ton
Near detector should look like
Far detector looks like
beam
35
0.28km
Far/near ratio (OA 2deg)spectrum
0.28km
1.5km
295km
2.0km
36
37
Strategy and Sensitivity Goal (Phase II)
Intensity upgrade to 4 MW 1 Mton far detector, Hyper-Kamiokande Search for CP violation
38
Hyper-Kamiokande (1Mt water) Precision neutrino oscillation study Proton decay search
R&D (complete in 2 years) Cavity excavation and its stability New light detector: Hybrid Photo-
Detector, HPD (50cm)
39
Sensitivity (3) to CPV (T2K Phase II)
Chooz excluded@m31~3x10-3eV2
>~27deg
>~14deg
Preliminary
4MW, 1Mt Fid.Vol.2yr for
6.8yr for
T2K1 3 discoverym21=5x10-5eV2
12=/8m32=m31=3x10-3eV2
23=/4
40
Conclusions
Rapid progress in measuring masses and mixing of neutrinosm23
2 = 1.3 - 3.0×10-3 eV2, sin2223 = 0.9 – 1.0m12
2 = 6 - 9×10-5 eV2, sin2212 = 0.7 – 0.9Their precisions need to be improved
23 and are still unknown
J-PARC can produce beam 100 times stronger than K2K (proton beam power; 0.75 MW)Sensitivities; sin2231 > 0.006 (90%CL)
If 31 measured, a further upgrade will be consideredproton beam power; 4 MW1 Mton Hyper-KA lot of uncertainties in future
Linear collider, budget deficit, etc
41
Supplement
42
JSNS23 neutron beam lines
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