δ? ( ) 3 9 5 Soo-Bong Kim (SNU)
"for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos Raymond Davis Jr. USA (University of Pennsylvania) Masatoshi Koshiba Japan (University of Tokyo) "for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources Riccardo Giacconi USA (Associated Universities Inc.)
Neutrinos can probe the interior of stars. Neutrinos are transparent to the Milky way. Neutrinos are efficient to carry out energies from the star explosion. Neutrinos from Sun, Supernova explosion, Galaxy, Dark-Matter Annihilation, etc.
Solar Neutrinos Atmospheric Neutrinos Supernova Neutrinos Cosmic Background Neutrinos Ultra High Energy Neutrinos
W. Pauli (1931): Undetectable neutral particle E. Fermi (1934) Neutrino F. Reines (1956): Discovery L. Lederman, M. Schwartz, J. Steinberg (196): Muon Neutrino R. Davis (1968): First detection of solar neutrinos M. Koshiba (1987): Supernova neutrinos by Kamiokande-II and IMB Y. Totsuka (1998): Oscillation of atmospheric neutrinos at Super- Kamiokande SNO (): Oscillation of solar neutrinos
(.) (1.3) (175 ) (.5) (.14) ( 4.) /3-1/3 (.5) (.16) (1.8) e -1 () () (8) (91)
GUT ( ) ( ) (MNS ) (,, )
να ν β () = ( cosθ ( ) sinθ ) ν 1 -sinθ cosθ ν P(ν α ν β ) = sin θ sin (1.7 m L/E) m = m -m 1 (ev ) L (km): Distance from source to detector E (GeV): Neutrino energy
Solar neutrino data (Super-Kamiokande, SNO) Atmospheric neutrino data (Super-Kamiokande) Neutrino beam data (KK)
C Scientific American Super- Kamiokande Water Cherenkov detector ν 1 m underground 5, ton (,5 ton fid.) 11,146 inch PMTs 1,885 anti-counter PMTs SK-I: Apr 1996 Jul 1 SK-II: Dec
SK-1 (Jan. 1996)
1 11 1 6777 ID + 11 OD PMTs destroyed
Encase all Never the existing PMTs repeat (546) in acrylic the + frpaccident cases to prevent shock wave generation
(Sep. 17, ) SK-II Resumed data-taking in Dec,!
Solar Neutrino Data of Super-Kamiokande ν E e = 5. - MeV e - ν e e ν e e scattering (contains 15% of NC) θ sun 385 solar ν events (14.5 events/day) 8 B flux :.35 ±. ±.8 Data SSM [x 1 6 /cm /sec] -.15 =.465 ±.5 +.16 COSθ sun
KamLAND (Confirmation of solar neutrino oscillations) m (ev ) 1-1 -3 From K.Inoue (Tohoku Univ.) 3 years 95% rate 1-4 LMA 95% 1-5 1-6 KamLAND sensitivity 6 ton, 5 years 8% reactor power shape analysis above.6 MeV 5% systematic error 1-1 1 sin θ
Solar neutrino oscillations (ν e ν µ /ν τ ) are established by Super-Kamiokande and SNO data. ( m 1 ~ 1-4 ev ) LMA solutions are favored by no spectrum distortion and no day/night effect. Large Mixing Angle(LMA) by a global fit:.5 x1-5 ev < m ( m 1 ) < 3.3 x1-4 ev.5 < tan θ <.9 (3σ C.L.) KamLAND confirmed the LMA at 4.6σ C.L. See also: Phys. Lett.. B539 179-187, 187,
Number of Events Number of Events 45 Sub-GeV e-like 4 35 3 5 15 1 5-1 -.5 cosθ.5 1 Multi-GeV e-like 14 1 1 Zenith Angle Distributions ν µ ν τ -flavor oscillations 8 6 4-1 -.5.5 1 cosθ Number of Events Number of Events 5 4 3 1 35 3 5 15 1 5 Sub-GeV µ-like -1 -.5.5 1 cosθ Multi-GeV µ-like + PC -1 -.5.5 1 cosθ Number of Events Number of Events Best fit ( m =.5x1-3 ev, sin θ=1. χ min=163./17 d.o.f) Null oscillation (χ =456.5/17 d.o.f) 5 45 4 35 3 5 15 1 5-1 -.5 cosθ.5 1 1 8 6 4 Sub-GeV Multi-ring µ like Multi-GeV Multi-ring µ like -1 -.5.5 1 cosθ Flux(1-13 cm - s -1 sr -1 ) Flux(1-13 cm - s -1 sr -1 ) 1.4 1. 1.8.6.4. 4 3.5 3.5 1.5 1.5 Upward Stopping µ -1 -.8 -.6 -.4 -. cosθ Upward Through Going µ -1 -.8 -.6 -.4 -. cosθ 13km 5km 15km 13km 5km
Evidence for neutrino oscillations and masses he most cited paper in the experimental particle physics (more than 1,6)
ν µ ν τ ( m 3 ) m (ev ) 1-1 ν µ ν τ Best fit( m =.5x1-3,sin θ=1. χ min=163./17 d.o.f) 1-1 -3 m 3 = (1.6~3.9)x1-3 ev sin θ 3 >.9 (9%CL) 1-4 FC+PC+UPMU combined FC+PC Upgoing through µ Upgoing stop µ/upgoing through µ.1..3.4.5.6.7.8.9 1 sin θ
3-flavor mixing θ 13?
ν e Solar ν m 1 ~1-4 ev ν µ Atmospheric ν m 3 =3x1-3 ev ν τ
Oscillation Probabilities when Atmospheric ν 3 m 1 << m3 m13 m 3 m m 1 θ 3 :ν µ disappearance P 4 µ x 1 cos θ 13 sin θ 3 sin ( 1.7 m L / E ) 3 ν θ 13 :ν e appearance common P Solar ν µ e sin θ 3 sin θ 13 θ 1 :ν e disappearance P + e 1 x sin cos θ 4 13 θ 13 sin θ 1 sin sin ( 1.7 m L / E ) 3 ( 1.7 m L / E ) 1 ν ν
3 1-1 ( m = m 3 m 13 ) 1-1 1-1 - 9% C.L. 99% C.L. m (ev ) 1-3 1-4 SK 9% C.L. SK 99% C.L. CHOOZ 9% CL exclude PALO VERDE 9 % CL exclude.1..3.4.5 sin θ 13 m (ev ) 1-3 1-4..4.6.8 1 sin θ 3 Pure ν µ ν τ getting close to CHOOZ s limit on θ13 Pure ν e ν τ Pure ν e ν µ consistent with CHOOZ s excluded region
ν µ ν τ flavor oscillations are established. ( m = m 3 m 13 >> m 1 ) m = (1.6~3.9)x1-3 ev sin θ 3 >.9 (9% C.L.) ν s admixture is disfavored (sin ξ<.19 @9%CL). 3 flavor oscillations are tested and give an allowed region of θ 13, consistent with CHOOZ: sin θ 13 <.1 (9% C.L.)
KK (KEK to Kamioka)
KEK (June 1999 July 1) Detector 1kt (5t, H O) SciFi (5.9t, H O+Al) MRD (73t, Fe) Neutrino Expectation Events at SK ~8, 8.6 ±.3(stat) +7.3-8. (sys) 7,4 87.6 ±1.3(stat) +1.6-11.9 (sys) ~15, 87.4 ±.4(stat) +1.7-13.9 (sys)
Super-K. T T SK TSpill TOF 1.3µ sec FC events events 1 3 1 1 1-5 -5 5 5 T (µsec) (T) µs 15 1 5 ±5µsec ±5µsec 56 events! No Decay-e HE Trig. FCFV 1.5µs -5 5 (T) µs T (µsec) T spill GPS T SK T Spill : Abs. time of spill start T SK : Abs. time of SK event TOF:.83ms (KEK to Kamioka) FC: fully contained (No activity in Outer Detector) FV:.5kt Fiducial Volume Expected Atm. ν BG <1-3 within 1.5µs.
Super-Kamiokande
KK Number of total interactions (Jun99-Jul1 ) N obs =56 N exp =8.1 +6. -5.4 Reconstructed Eν shape of 1-RFCµ (9 1-R events in Nov99-Jul1) Events 1 9 8 7 no oscillation Normalized by area 6 #Events + 5 4 3 Best w/ oscillations fit point (KS-test = 79%) 1 Protons on target (E18).5 1 1.5.5 3 3.5 4 4.5 5 E ν rec GeV
KK KK Best fit point = (1.,.8x1-3 ev ) Method1.8x1-3 Method.7x1-3 Super-K result Null oscillation probability < 1% Method1.7% Method.4% Two independent methods agree with each other
(!) MNS(Maki-Nakagawa-Sakata) = 3 1 ν ν ν ν ν ν α τ µ i e U = 1 cos sin sin cos cos sin 1 sin cos cos sin sin cos 1 1 1 1 1 13 13 13 13 3 3 3 3 θ θ θ θ θ θ θ θ θ θ θ θ δ δ i i e e U ij j j j i i i U U U U Φ = > * * )sin Re( 4 ) P( β α β α αβ β α δ ν ν ij j j j i i i U U U U Φ ± > * * )sin Im( β α β α [GeV] [km]/ ] [ev m 1.7 4 / m ν E ν L E L ij ij ij = Φ ) m m m ( 31 3 1 = + +
JHF- (7)