takaaki kajita icrr, univ. of tokyo
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Takaaki Kajita
ICRR, Univ. of Tokyo
KIAS, Seoul, Nov. 2005
Fig: Senda NP-4
Non-LBL physics with large water Cherenkov detectors
• Atmospheric neutrinos
(300 events /day)• Proton decay• Supernova neutrinos (200,000 events for
SN @galactic center) • Supernova relic neutrinos• Solar neutrinos (300-400 events/day)• ……
Outline• Assumptions
• Neutrino oscillation physics with atmospheric neutrinos
• Proton decay
• Comment on photo cathode coverage
• Summary
Apology: references incomplete…
Assumptions Assumptions
JPARC
Fig: Talk by K.Senda @NP04 (also, hep-ph/0504061)
Off-axis angleDistance from the target (km)
1) Fid. MassKamioka+Korea=0.54 Mton
2) Detector performance = Super-K
1) Fid. MassKamioka+Korea=0.54 Mton
2) Detector performance = Super-K
Neutrino oscillation physics with Neutrino oscillation physics with atmospheric neutrinosatmospheric neutrinos
TK NNN05
e
3
21
Solar,
KamLAND
Solar,
KamLAND
Atmospheric
Long baseline
Atmospheric
Long baseline
12, m122
mass and mixing parameters: 12, 23, 13, , m12
2, m13
2(=m232)
Known:Known: 23, |m232|
KamLAND SNO(+Super-K) Super-K K2K Reactor solar atmospheric long baseline
mass and mixing parameters: 12, 23, 13, , m12
2, m13
2(=m232)
Unknown:Unknown:
13
Sign of m232
or
CP ?
Future long baseline eperiments JPARC-Kamioka-Korea (Atmospheric neutrino exp.s could help….)
Future long baseline eperiments JPARC-Kamioka-Korea (Atmospheric neutrino exp.s could help….)
3
21
e
If 23 ≠/4, is it >/4 or </4 ?
3
or
e
Atmospheric neutrino
experiments
Atmospheric neutrino
experiments
Near future reactor, LBL
exp’s
3
s2212=0.825 m212=8.3×10-5
m223=2.5×10-3
sin213=0
Because of the LMA solution, atmospheric neutrinos should also oscillate by (12, m12
2).
Oscillation probability is different between s223=0.4 and 0.6 discrimination between 23 >/4 and </4 might be possible.
However, due to the cancellation betw
een e and e
, the change i
n the e flux is small.
Peres & Smirnov NPB 680 (2004)
479
Solar term effect to atmospheric Solar term effect to atmospheric
Effect of the solar term to sub-GeV e-like zenith anEffect of the solar term to sub-GeV e-like zenith anglegle
sub-GeV e-like
m212 = 8.3 x 10-5 eV2
m223 = 2.5 x 10-3 eV2
sin2 212 = 0.82sin213=0
sin2 23 = 0.4sin2 23 = 0.5sin2 23 = 0.6
(Pe :100 ~ 1330 MeV) (Pe :100 ~ 400 MeV) (Pe :400 ~ 1330 MeV)
coszenith
e-lik
e (3
fla
vor)
/ e
-like
(2
flavo
r fu
ll-m
ixin
g)
(Much smaller and opposite effect for -like events.)
/e ratio @low energy is useful to discriminate 23
>/4 and </4.
Effect Effect of the of the solar termssolar terms to the to the sub-GeV sub-GeV /e ratio/e ratio (zenith angle dependence)(zenith angle dependence)
sub-GeV P , e < 400 MeV P , e > 400 MeV
m212 = 8.3 x 10-5 eV2
m223 = 2.5 x 10-3 eV2
sin2 212 = 0.82sin213=0
(e
) (3
fla
vor)
(e
) (2
fla
vor
full-
mix
ing)
sin223 = 0.6
sin223 = 0.4sin223 = 0.5
2 flavor (sin2223=.96)
It could be possible to discriminate the octant of 23, if sin223 is significantly away from 0.5.
It could be possible to discriminate the octant of 23, if sin223 is significantly away from 0.5.
Expected oscillation with Expected oscillation with solar terms (2)solar terms (2)
s2212=0.825 m212=8.3×10-5
m223=2.5×10-3
s223=0.4 s213=0.0
Effect of LMA
s223=0.4 s213=0.04cp=/4
Effect of 13
Interference(CP)
)(
)(
oscnoflux
oscflux
e
e
= 1 + P2 (r cos2 23 – 1)P2 = 2 transition probability e in matter driven by m12
2
)(
)(
oscnoflux
oscflux
e
e
In addition, we may have non-zero 13.
E
Lm
P e
2232
13
2
23
2 27.1sin2sinsin
)(
Search for non-zero Search for non-zero 13 13
E
Lm
P e
22
13
2
23
2 27.1sin2sinsin
)(
E
Lm
P e
22
13
2
23
2 27.1sin2sinsin
)(
(m122=0 assumed)
E(GeV)
cos
zeni
th )( eP
Matter effect
s213=0.05 s213=0.00 null oscillation
Electron appearance 1+multi-ring, e-like, 2.5 - 5 GeV
0.45Mtonyr
cos
0.45 Mtonyr
3
Approximate CHOOZ
bound
Binning for this study (= osc. analysis in SK)Binning for this study (= osc. analysis in SK)
E
Single-Ring
Multi-Ring
Up-stop
Up-through
37 momentum bins x 10 zenith bins = 370 bins in total37 momentum bins x 10 zenith bins = 370 bins in total
Multi-Ring e
Single-Ring e
PC-stop
PC-through
10 zenith angle bins for each box.
10 zenith angle bins for each box.
Small number of events per binSmall number of events per bin
Poisson statistics to claculate 2 with 45 systematic error termsPoisson statistics to claculate 2 with 45 systematic error terms
Multi-GeV
Sub-GeV
CC e CC
For more details: please ask H.K.Seo and S.Nakayama
0.092 Mtonyr Super-K data0.092 Mtonyr Super-K data
Analysis with and w/o solar
terms
with 12 terns(best fit s223
= 0.51)
w/o 12
3
2
1
sin223
sin2
13
Search for non-zero 13
E(GeV)
cos
zeni
t
h
)( eP
Discrimination between Discrimination between 23 23 >>/4 and </4 and </4 /4 with the (12) and (13) termswith the (12) and (13) terms s223=0.40 ~ 0.60
s213=0.00~0.04 cp=45o
Discrimination between 23>/4 and </4 is possible for all 13.
Discrimination between 23>/4 and </4 is possible for all 13.
1.8Mtonyr (or 3.3yr×0.54Mton)
1.8Mtonyr (or 3.3yr×0.54Mton)
Discrimination between 23>/4 and </4 is marginally possible only for s213 >0.04.
Discrimination between 23>/4 and </4 is marginally possible only for s213 >0.04.
sin223 sin223
sin2
13
sin2223=0.96 sin2223=0.99
90%CL 90%CL
Test point
Fit result
M.Shiozawa et al, RCCN Int. Workshop on sub-dom. Atm. Osc. 2004
Improvement Improvement possible ?possible ?
m212 = 8.3 x 10-5 eV2
m223 = 2.5 x 10-3 eV2
sin2 212 = 0.82sin213=0
P , e < 400 MeV
sin223 = 0.6
sin223 = 0.4sin223 = 0.5
2 flavor (sin2223=.96)
(e
) (3
fla
vor)
(e
) (2
fla
vor
full-
mix
ing)
tru
e
0.8 Mtonyr = SK 20yr = HK 0.8yr0.8 Mtonyr = SK 20yr = HK 0.8yr
S.Nakayama, RCCN Int. Workshop on sub-dom. Atm. Osc. 2004
Search for proton decay Search for proton decay
Lifetime in benchmark scenarios
J.Ellis NNN05 C.K.Jung NNN05
How long is the predicted proton lifetime ?
SK limit (e0)
SK limit (K+)
Search for pSearch for pee++00
Ptot < 250 MeV/c, BG 2.2ev/Mtyr, eff=40% Ptot < 100 MeV/c, BG 0.15ev/Mtyr, eff=17%
Atm 20Mtonyr
free proton decay
bound proton decay
Main target is free proton decays for the tight cut.
pe0 Monte Carlope0 Monte Carlo
e+e+
00
M.Shiozawa NNN05
Now (near future)Future
Lifetime sensitivity for pLifetime sensitivity for pee++00
Normal cut, 90%CL 3 CLTight cut, 90%CL 3 CL
pe+0 sensitivity
5Mtonyrs ~1035 years@90%CL~4x1034 years@3CL
5Mtonyrs5Mtonyrs
ppKK++ (1) 16OOK+15N , , KK++→→
e+236MeV/c6 – 10 Me
V
Signal region
Background = 0.7= 8.6%Candidate = 0
NPMT-hit distribution for the prompt gamma search
(Also, searches for
(2) pK+ (K++0)
(3) PK+(K++, without ) )
νKνK++ sensitivity (based on SK criteria) sensitivity (based on SK criteria)
τ/B > 2 × 1034yr (5Mtonyr, 90%CL)
Question: How much photo cathode coverage is necessary?Question: How much photo cathode coverage is necessary?
Most updated number = 2,3×1033 yrs
Most updated number = 2,3×1033 yrs
5Mtonyrs5Mtonyrs
e
cMeV
MeVN
NKO
)/236(
)6(15
*1516
12nsec
2.2sec
Photo cathode coverage ?Photo cathode coverage ?• Cost for the photo-detectors is a significant part of the total detector cost.
• If 40% coverage with 50cm diameter PMT’s for 0.27 Mton fiducial mass; 100,000 PMT’s. If 100 (200?) $ / PMT 100M$ (200?M$)
• Important to understand minimum requirement of photo-coverage from each physics topics
• SK-II (19% coverage SK-I 40%) is a good opportunity to investigate physics sensitivity with reduced photo- coverage. LBL physics
Atmospheric neutrinos Proton decay (e0) This talk Proton decay (K+) Astrophysical neutrinos (SN, solar neutrinos? ...)
Proton mass vs. momentumProton mass vs. momentum
SK-I=40.1%
SK-I8 /2.2Mtyr
SK-II2 /0.45Mtyr
SK-II=41.1%
atm(BG) MC pe0 MC
Proton mass and momentumProton mass and momentum
SK-I SK-I
SK-IISK-II
pe0 MC
p mom. resolution; 177MeV(68%)171 ( free proton) 81MeV(68%)83
p mom. resolution; 177MeV(68%)171 ( free proton) 81MeV(68%)83
p mass resolution; 33.8MeV42.3 (free proton) 28.5MeV35.2
p mass resolution; 33.8MeV42.3 (free proton) 28.5MeV35.2
pe0 looks OK with 20% photo cathode coverage. pe0 looks OK with 20% photo cathode coverage.
Photo cathode coverage ?Photo cathode coverage ?
LBL physics Need careful checks
Atmospheric neutrinos 20% probably OK. (No proof today…)
Proton decay (e0) 20% looks OK.
Proton decay (K+) We will know in a month or half a year… Astrophysical neutrinos (SN, solar ? ...) Need checks…
• Mton class water detectors will have a lot of physics opportunities.
• Mton class detectors can not be cheap. Therefore it is very nice that it could carry out many important physics.
End
Solar neutrino physics with Mton detectors Solar neutrino physics with Mton detectors
Solar global
KamLAND
Solar+KamLAND
95%
99.73%P( e
e)
Vacuum osc. dominant
matter osc.
(MeV)
Do we want further evidence for matter effect ?
M.Nakahata NNN05
Day-night asymmetry
Expected signalExpected signal8B spectrum distortion
Enough statistics to see distortion.
Energy scale calibration should be better than ~0.3%.
Ee (MeV)
Dat
a/S
SM
5 Mton·years
Correlated sys. error of SK
sin2=0.28,
m2 =8.3×10-5 eV2
1/2 of SK
Day-night stat. significance
3 signal can be obtained with 0.5% day-night systematic error.
In both cases, systematic errors or background are assumed to be better than SK.
Supernova events in a Mega-ton detectorSupernova events in a Mega-ton detectorA.Dighe NNN05
Number of anti-e+p interactions = 200,000 - 300,000 for a galactic Supernova (@10kpc)
◆Initial spectra rather poorly known.
◆Only anti-e observed
Difficult find a “clean” observable, which is (almost) independent of the assumptions on the initial spectra.
◆Initial spectra rather poorly known.
◆Only anti-e observed
Difficult find a “clean” observable, which is (almost) independent of the assumptions on the initial spectra.
Supernova shock and neutrino oscillationsSupernova shock and neutrino oscillationsAssume: nature = inverted hierarchy
Assume: nature = inverted hierarchy
Anti-eAnti-e
If sudden change in the average energy is observed Inverted mass hierarchy and sin213>10-5.
If sudden change in the average energy is observed Inverted mass hierarchy and sin213>10-5.
sin213
Forward shock
Reverse shock
m132 resonance
m122 resonance
A.Dighe NNN05R.Tomas et al., astro-ph/0407132
Mton is large: Mton is large: TThe detectors can see extragalactic SNehe detectors can see extragalactic SNe
Nearby SN rate
SK
HK
Detection probability
S.Ando NNN05
Supernova relic neutrinos (SRN)Supernova relic neutrinos (SRN)
SRN prediction
SK result
e+anti-e
Invisible e
SNR limit90%CL
90%CL limit: 1.2 /cm2/sec (E>19MeV)(which is just above the most recent prediction 1.1/cm2/sec)
get information on galaxy evolution and cosmic star formation rate get information on galaxy evolution and cosmic star formation rate
With a Mton detector, it must be possible to see SRN signal With a Mton detector, it must be possible to see SRN signal
S.Ando,M.Nakahata NNN05
Mton detector with Gd loaded waterMton detector with Gd loaded waterGADZOOKS! M.Vagins NNN05
B.G. reduction by neutron tagging
No neutron tagging
Statistically 4.6excess (Evis > 15 MeV)
Simulation: M.Nakahta NNN05
)8('
MeVEsGdGdn
nepe
(0.2% GdCl3)
M.Vagins, J.Beacom hep-ph/0309300
Invisible e
End
45 systematic 45 systematic error terms error terms
(0, Free parameter) Flux, Nu-int, Fit; absolute normalization(1) Flux; (nu_mu + anti-nu_mu) / (nu_e + anti-nu_e) ratio ( E_nu < 5GeV )(2) Flux; (nu_mu + anti-nu_mu) / (nu_e + anti-nu_e) ratio ( E_nu > 5GeV )(3) Flux; anti-nu_e / nu_e ratio ( E_nu < 10GeV )(4) Flux; anti-nu_e / nu_e ratio ( E_nu > 10GeV )(5) Flux; anti-nu_mu / nu_mu ratio ( E_nu < 10GeV )(6) Flux; anti-nu_mu / nu_mu ratio ( E_nu > 10GeV )(7) Flux; up/down ratio(8) Flux; horizontal/vertical ratio(9) Flux; K/pi ratio(10) flight length of neutrinos(11) spectral index of primary cosmic ray above 100GeV(12) sample-by-sample relative normalization ( FC Multi-GeV )(13) sample-by-sample relative normalization ( PC + Up-stop mu )(14) MA in QE and single-(15) QE models (Fermi-gas vs. Oset's)(16) QE cross-section (17) Single-meson cross-section (18) DIS models (GRV vs. Bodek's model)(19) DIS cross-section (20) Coherent- cross-section (21) NC/CC ratio(22) nuclear effect in 16O(23) pion spectrum(24) CC cross-section
(25) Reduction for FC(26) Reduction for PC(27) Reduction for upward-going muon(28) FC/PC separation(29) Hadron simulation (contamination of NC in 1-ring -like)(30) Non- BG ( flasher for e-like )(31) Non- BG ( cosmic ray muon for mu-like )(32) Upward stopping/through-going mu separation(33) Ring separation(34) Particle identification for 1-ring samples(35) Particle identification for multi-ring samples(36) Energy calibration (37) Energy cut for upward stopping muon(38) Up/down symmetry of energy calibration (39) BG subtraction of up through (40) BG subtraction of up stop (41) Non-e contamination for multi-GeV 1-ring electron (42) Non-e contamination for multi-GeV multi-ring electron (43) Normalization of multi-GeV multi-ring electron(44) PC stop/through separation
Flux (13)Flux (13)
interaction (11) interaction (11)
Detector, reduction and reconstruction (20)Detector, reduction and reconstruction (20)
sub-GeV -like zenith angle
sub-GeV -like
(P : 200 ~ 1330 MeV)
m212 = 8.3 x 10-5 eV2
m223 = 2.5 x 10-3 eV2
sin2 212 = 0.82
sin2 23 = 0.4sin2 23 = 0.5sin2 23 = 0.62 flavor (sin2 223 = 0.96)
X : zenith angleY : N_ (3 flavor) / N_ (2 flavor full-mixing)
(P : 200 ~ 400 MeV) (P : 400 ~ 1330 MeV)
Discrimination between Discrimination between 23 23 >>/4 and </4 and </4 /4 with the (12) and (13) termswith the (12) and (13) terms s223=0.40 ~ 0.60
s213=0.00~0.04 cp=45o
Discrimination between 23>/4 and </4 is possible for all 13.
Discrimination between 23>/4 and </4 is possible for all 13.
1.8Mtonyr = SK 80 yrs = 3.3 HK yrs1.8Mtonyr = SK 80 yrs = 3.3 HK yrs
Discrimination between 23>/4 and </4 is marginally possible only for 13 >0.04.
Discrimination between 23>/4 and </4 is marginally possible only for 13 >0.04.
sin223 sin223
sin2
13
sin2223=0.96 sin2223=0.99
90%CL 90%CL
Test point
Fit result
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