JHF-Kamioka Neutrino Oscillation Experiment using JHF 50 GeV PS Y.Itow ICRR,Univ.of Tokyo Jul27,2002 Jul27,2002 ICHEP02 Amsterdam Introduction Facility Physics goal Summary

Where we go ? Discovery Phase K2K The 1 st long baseline experiment Atmospheric Discovery of  oscillations  m 23 2 ~ 1.6 – 3.9×10 -3 eV 2 sin 2 2  23 > 0.92 Solar Large mixing in  e oscillations  m 12 2 ~ ×10 -5 eV 2 sin 2 2  12 ~ Precision study of 3-flavor mixing matrix Cosmic ray Precision Study Phase Accelerator

 12,  23,  13 +   m 2 12,  m 2 23 MNS (Maki-Nakagawa-Sakata) matrix 3 Flavor Mixing

3-flavor Oscillation Oscillation Probabilities when     e appearance      disappearance common m1m1 m2m2 m3m3   CP in e appearance

Strategy High statistics by high intensity beam High statistics by high intensity beam Tune E at oscillation maximum Tune E at oscillation maximum Narrow band beam to reduce BG Narrow band beam to reduce BG Sub-GeV beam for Water Cherenkov Sub-GeV beam for Water Cherenkov 0.75MW JHF 50GeV-PS Off-Axis beam Super-Kamiokande

~1GeV beam Kamioka JAERI (Tokai) 0.75MW 50 GeV PS ( conventional beam) Super-K: 22.5 kt JHF 0.75MW + Super-Kamiokande Plan to start in 2007 (hep-ex/ ) 4MW 50 GeV PS Hyper-K: 1000 kt Future Super-JHF 4MW + Hyper-K ~ JHF+SK  200 JHF-Kamioka Neutrino Experiment

Organization 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 Experiment working group  Dec.1999: formed (ICRR/KEK/Kyoto/Kobe/Tohoku/TRIUMF)  Jun.2001: Letter of Intent (hep-ex/ )  Mar.2002: Meeting to discuss possibility to organize international collaboration

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) (0.77MW)  8 bunches/~5  s  3.3x10 14 proton/pulse  3.94 (3.64) sec cycle  1 ｙｒ ≡10 21 POT (130 days) Near detectors (280m,2km) beam-line budget request submitted Target station Decay volume Transport line (Super-cond. Mag.)

 OA2° Osc. Prob.= sin 2 (1.27  m 2 L/E )  m 2 =3x10 -3 eV 2 L=295km osc.max. Off Axis Beam (ref.: BNL-E889 Proposal)  Target Horns Decay Pipe Super-K.  Quasi Monochromatic Beam  x2~3 intense than NBB Statistics at SK (OAB2deg,1yr,22.5kt) ~4500  tot ~3000  CC e ~0.2% at  peak ~10 2 x (K2K) Tuned at oscillation maximum Oscillation probablity

Assume CC Quasi Elastic (QE) reaction  p ccQE inelastic  + n →  + p +n  E reconstruction in water Cherenkov  + n →  + p ( E , p  ) beam energy ccQE cc-inelastic

Detectors Muon ~140m Muon ~140m Spill-by-spill monitoring of beam direction Spill-by-spill monitoring of beam direction First Front First Front Neutrino intensity/direction Neutrino intensity/direction Second Front ~2km Second Front ~2km Almost same E spectrum as for SK Almost same E spectrum as for SK Water Cherenkov can work Water Cherenkov can work Far 295km Far 295km Super-Kamiokande (50kt) Super-Kamiokande (50kt) 1.5km 295km 0.28km Neutrino spectra at diff. dist dominant syst. in K2K p  140m0m280m2 km295 km

Far detector Super-Kamiokande （ since Apr 1 ９９ ６） ４０ｍ ４１．４ｍ 50,000 ton water Cherenkov detector (22.5 kton fiducial volume)

Re-Construction of Super-K (Jul 2002)

★ Precise measurement of neutrino mixing matrix Accuracy: sin 2 2θ 23 ・・・・・・ 1% Δm 2 23 ・・・・・・・・・・ a few % ★ Discovery and measurement of non-zero θ 13 sin 2 2θ 13 ・・・・・・ > st Evidence of 3-flavor mixing ! 1 st step to CP measurement Physics Goal

 (sin 2 2   )  (  m 23 2 ) True  m 23 2 (eV 2 ) OAB-2degree,5yr  (sin 2 2  )~0.01  (  m 2 ) ~<1×10 -4 Measurement of sin 2 2θ 23,  m 2 23  disappearance ~3% m2m2 sin 2 2 

 e appearance in JHF-Kamioka e appearance in JHF-Kamioka e 00 Back ground for e appearance search Intrinsic e component in initial beam Merged  0 ring from  interactions 10% uncertainty for BG estimation The 1kt  0 data will be studied for exercise

sin 2 2  13 from e appearance sin 2 2  13 Background in Super-K (as of Oct 25, 2001) Signal Signal + BG  e  etotal sin 2 2  13 m2m2 Off axis 2 deg, 5 years at Sin 2 2  13 >0.006 CHOOZ excluded

Future upgrade Super-JHF(4MW)+Hyper-K(1Mt) ~1,000 kt Candidate site in Kamioka Good for atm. proton decay

Sensitivity(3  ) to CP violation (SuperJHF+Hyper-K) Chooz  m 31 ~3x10 -3 eV 2  >~27deg  >~14deg Preliminary 4MW,1Mt 2yr for  6.8yr for  JHF1 3  discovery

JHF- construction physics run (OAB) MINOS 2yr OPERA 5yr Global Schedule SK rebuild SK-half SK-full

Summary Precision study of neutrino mixing matrix Precision study of neutrino mixing matrix Next step after the discovery Next step after the discovery We may find a hint for next break-through We may find a hint for next break-through JHF-Kamioka neutrino experiment (2007~) JHF-Kamioka neutrino experiment (2007~) JHF 0.75MW 50GeV-PS+Off Axis beam+Super-K JHF 0.75MW 50GeV-PS+Off Axis beam+Super-K Narrow band beam at oscillation maximum (~ 1GeV) Narrow band beam at oscillation maximum (~ 1GeV) e appearance, discovery of  13 (sin  13 >0.006,90%CL) e appearance, discovery of  13 (sin  13 >0.006,90%CL) Budget request submitted, R&D started Budget request submitted, R&D started Possible upgrade in future Possible upgrade in future 4MW Super-JHF + Hyper-K ( 1Mt water Cherenkov) 4MW Super-JHF + Hyper-K ( 1Mt water Cherenkov) CP violation in lepton sector CP violation in lepton sector Bonus ! (Proton Decay ! ) Bonus ! (Proton Decay ! )