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JHF-Kamioka Neutrino Oscillation Experiment using JHF 50 GeV PS. Y.Itow ICRR,Univ.of Tokyo Jul27,2002 ICHEP02 Amsterdam. Introduction Facility Physics goal Summary. Atmospheric n. D m 23 2 ~ 1.6 – 3.9×10 -3 eV 2. sin 2 2 q 23 > 0.92. Discovery of n m oscillations.
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JHF-Kamioka Neutrino Oscillation ExperimentusingJHF 50 GeV PS Y.Itow ICRR,Univ.of Tokyo Jul27,2002 ICHEP02 Amsterdam • Introduction • Facility • Physics goal • Summary
Atmospheric n Dm232 ~ 1.6 – 3.9×10-3 eV2 sin22q23>0.92 Discovery of nm oscillations Solar n Dm122 ~ 3 - 20×10-5 eV2 sin22q12~0.55- 0.95 Large mixing in ne oscillations K2K The 1st long baseline n experiment Precision Study Phase Accelerator Precision study of 3-flavor n mixing matrix Where we go ? Discovery Phase Cosmic ray
3 Flavor Mixing Dm212, Dm223 q12, q23, q13 + d MNS (Maki-Nakagawa-Sakata) matrix
m3 m2 m1 • d: CP in ne appearance 3-flavor Oscillation Oscillation Probabilities when • q23 :nm disappearance • q13:ne appearance common
Strategy • High statistics by high intensity n beam • Tune En at oscillation maximum • Narrow band beam to reduce BG • Sub-GeV n beam for Water Cherenkov 0.75MW JHF 50GeV-PS Off-Axis n beam Super-Kamiokande
Hyper-K: 1000 kt 4MW 50 GeV PS Future Super-JHF 4MW + Hyper-K ~ JHF+SK 200 JHF-Kamioka Neutrino Experiment (hep-ex/0106019) Plan to start in 2007 Kamioka ~1GeV n beam JAERI (Tokai) Super-K: 22.5 kt 0.75MW 50 GeV PS ( conventional n beam) JHF 0.75MW + Super-Kamiokande
Organization • Experiment working group • Dec.1999 : formed (ICRR/KEK/Kyoto/Kobe/Tohoku/TRIUMF) • Jun.2001 : Letter of Intent (hep-ex/0106019) • Mar.2002 : Meeting to discuss possibility to organize international collaboration Facility Construction Group • Officially formed in KEK on April, 2001 • The 3rd physics division, IPNS, Cryogenic facility group, Cryogenic Science Center, w/ strong support from KEK-PS beam channel group
JHF-SK Neutrino Working Group ICRR/Tokyo-KEK-Kobe-Kyoto-Tohoku-TRIUMF Y. Itow, T. Kajita, K. Kaneyuki, Y.Obayashi, C.Saji, M. Shiozawa, Y. Totsuka (ICRR/Tokyo) Y. Hayato, A.Ichikawa, T. Ishida, T. Ishii, T. Kobayashi, T. Maruyama, K. Nakamura, Y. Oyama, M. Sakuda (KEK) S. Aoki, T.Hara, A. Suzuki (Kobe) T. Nakaya, K. Nishikawa (Kyoto) T. Hasegawa, K. Ishihara (Tohoku) A.Konaka (TRIUMF, CANADA) In addition to the above user group, the neutrino facility construction group is OFFICIALLY formed at KEK.
JHF Facility Construction 2001~2006 (approved) Transport line (Super-cond. Mag.) n beam-line budget request submitted (0.77MW) Target station • 8 bunches/~5ms • 3.3x1014proton/pulse • 3.94 (3.64) sec cycle • 1yr≡1021POT (130 days) Decay volume Near detectors (280m,2km)
Super-K. q Decay Pipe Target Horns Off Axis Beam (ref.: BNL-E889 Proposal) Osc. Prob.=sin2(1.27Dm2L/En) • Quasi Monochromatic Beam • x2~3 intense than NBB Oscillation probablity Dm2=3x10-3eV2 L=295km osc.max. Statistics at SK (OAB2deg,1yr,22.5kt) ~4500 nm tot ~3000 nm CC ne ~0.2% at nm peak OA2° ~102 x (K2K) nm Tuned at oscillation maximum
nm + n → m + p (Em, pm) n inelastic nm + n → m + p +np cc-inelastic ccQE ccQE beam energy En reconstruction in water Cherenkov Assume CC Quasi Elastic (QE) reaction m p
Neutrino spectra at diff. dist 1.5km 295km 0.28km dominant syst. in K2K Detectors p p n • Muon monitors @ ~140m • Spill-by-spill monitoring of beam direction • First Front detector@280m • Neutrino intensity/direction • Second Front Detector @ ~2km • Almost same En spectrum as for SK • Water Cherenkov can work • Far detector @ 295km • Super-Kamiokande (50kt) 0m 140m 280m 2 km 295 km
Far detectorSuper-Kamiokande 41.4m 40m (since Apr 1996) 50,000 tonwater Cherenkov detector(22.5 kton fiducial volume)
Physics Goal ★Precise measurement of neutrino mixing matrix Accuracy: sin22θ23・・・・・・ 1% Δm223・・・・・・・・・・ a few % ★Discovery and measurement of non-zero θ13 sin22θ13・・・・・・ > 0.006 1st Evidence of 3-flavor mixing ! 1st step to CP measurement
d(sin22q23) OAB-2degree,5yr d(Dm232 ) True Dm232 (eV2) Measurement of sin2 2θ23 , Dm223 nm disappearance sin22q ~3% Dm2 d(sin22q)~0.01 d(Dm2) ~<1×10-4
m e p0 ne appearance in JHF-Kamioka • Back ground for ne appearance search • Intrinsic ne component in initial beam • Merged p0 ring from nm interactions 10% uncertainty for BG estimation The 1kt p0 data will be studied for exercise
sin22q13 from ne appearance at Off axis 2 deg, 5 years CHOOZ excluded Dm2 Off axis 2 deg, 5 years Sin22q13>0.006 0.5 sin22q13
Future upgradeSuper-JHF(4MW)+Hyper-K(1Mt) Good for atm. n proton decay ~1,000 kt Candidate site in Kamioka
4MW,1Mt 2yr for nm 6.8yr for nm Sensitivity(3s) to CP violation (SuperJHF+Hyper-K) Chooz excluded @Dm31~3x10-3eV2 d>~14deg d>~27deg Preliminary JHF1 3s discovery
Global Schedule 2002 2004 2006 2008 2010 JHF-n construction physics run (OAB) SK rebuild SK-half SK-full MINOS 2yr OPERA 5yr
Summary • Precision study of neutrino mixing matrix • Next step after the discovery • We may find a hint for next break-through • JHF-Kamioka neutrino experiment (2007~) • JHF 0.75MW 50GeV-PS+Off Axis beam+Super-K • Narrow band beam at oscillation maximum (~ 1GeV) • ne appearance, discovery of q13 (sin q13>0.006,90%CL) • Budget request submitted, R&D started • Possible upgrade in future • 4MW Super-JHF + Hyper-K ( 1Mt water Cherenkov) • CP violation in lepton sector • Bonus ! (Proton Decay ! )