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Overview of the experiment Physics Motivation JHF facility and n beam Physics Sensitivity

日本物理学会・新潟大学 2000 年 9 月 23 日 宇宙線、素粒子論、素粒子実験 合同シンポジウム. JHF ニュートリノ実験. 中家　剛　（京大理）. Overview of the experiment Physics Motivation JHF facility and n beam Physics Sensitivity Additional Options Summary and Conclusion. 1. Overview of the experiment. ~1GeV n beam. Kamioka.

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Overview of the experiment Physics Motivation JHF facility and n beam Physics Sensitivity

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  1. 日本物理学会・新潟大学 2000年9月23日 宇宙線、素粒子論、素粒子実験 合同シンポジウム JHFニュートリノ実験 中家　剛　（京大理） Overview of the experiment Physics Motivation JHF facility and n beam Physics Sensitivity Additional Options Summary and Conclusion

  2. 1. Overview of the experiment ~1GeV n beam Kamioka Super-K: 50 kton Water Cherenkov JAERI (Tokaimura) 1 MW 50 GeV PS ( conventional n beam) • Precision measurement of n oscillation parameters by nm→ nx(sin22q23、Dm232). • Discovery of nm→ ne(sin22q13) • Confirmation of nm→ ntwith p0 in Neutral Current (NC).

  3. 1km(2700mwe) 3km 2km Mozumi Atotsu Super Kamiokande (far detector) 41.4m Outer detector 1867 of 8” PMT Ikeno-yama Kamioka, Gifu 50kton stainless steel tank 39.3m Inner detector 11146 of 20” PMT thanks to Kamiokande/Super-Kamiokande to make a neutrino physics so exciting.

  4. JHF Neutrino Working Group ICRR/Tokyo-KEK-Kobe-Kyoto-Tohoku-TRIUMF Y.Itow, Y.Obayashi, Y.Totsuka (ICRR/Tokyo) Y.Hayato, T.Kobayashi, K.Nakamura, M.Sakuda(KEK) T.Hara (Kobe) T.Nakaya, K.Nishikawa (Kyoto) T.Hasegawa, K.Ishihara, A.Suzuki (Tohoku) A.Konaka (TRIUMF) 15,5

  5. L=Σ(√M/v)yFy (Higgs Interaction) 2 2.Physics Motivation • Study n oscillation phenomena with a great precision. well known Not well known lepton quark MNSMatrix (Maki-Nakagawa-Sakata) KM Matrix (Kobayashi-Maskawa) Within SM: mass and mixing angles are free parameters Beyond SM(or GUT) : A prediction and a relation

  6. U= • MNS Matrix sij=sinqij、cij=cosqij Dmij2=Dmi2-Dmj2 Dm122 、Dm232 、 q12、 q23、 q13、 d solar n and reactor n ○ ○ ○ (size) ○ ○ LBL and atm. n (JHF-n) Future LBL (n factory or JHF-n -II) ○ (sign) ○

  7. Dm232 andq23 measurement P(nm→nm)=1 - cos4q13sin22q23sin2(1.27 Dm232 L/E) ~1 sin22q • Dm232 • Mass is a basic parameter. • If m3>>m2, the measurement is the mass itself which indicates a scale at high energy. <= GUT • q23 • q23 =p/4 or NOT (several predictions from GUT) • sin22q = 0.93 (Yanagida and Fukugita) = 0.81-0.96 (J. Pati, hep-ph/0005095) P(nm→ nm) Dm2 En (GeV)

  8. q13 measurement P(nm→ne)=sin22q13sin2q23sin2(1.27 Dm232 L/E) • A mixing angle between 1st and 3rd generation in MNS. • q13may be just below the CHOOZ limit, and nm→ne is waiting to be discovered. sin22q13= 0.014 (SU(5)-GUT, hep-ph/0007254) = 0.01-0.09 if LMA (PRL84, 3535 (2000)) ~ 0 • A discovery of nm→ne can open the new window to study CP violation in this mode. may be a source of baryogenesis in the universe.

  9. Non standard n oscillation hep-ph/0002199 • Large Extra Dimension • A sterile neutrino (LSND result? 3 or 4 n’s) • non standard CP violation of nm→nt . • (see Yasuda-san’s talk at PA08d (neutrino), ICHEP 2000) • Any other unexpected phenomena standard P(nm→ nx) L/E

  10. N 50GeV PS 3GeV PS Neutrino Beam Line 600MeV Linac FD To SK 3. JHF facility and n beam JAERI@Tokai-mura (60km N.E. of KEK) Construction 2001～2006 1021POT(130day)≡ “1 year”

  11. n beam at JHF • Principle • Intense • Beam energy is tuned to be at the oscillation maximum. • High sensitivity • Less background • ~1 GeV beam energy for Quasi-elastic interaction. Dm2= 2～5x10-3eV2 En=0.5～1.2GeV Wide Band Beam +-200MeV En(reconstruct) – En (True) (MeV)

  12. 3 beam configurations. • Wide Band beam (WBB) • High n flux • Broad n energy spectrum • Narrow Band Beam (NBB) • Tuned n energy (Flexible) • Off Axis Beam (OAB) • Tuned n energy (Fixed)

  13. Wide Band Beam 2 horns (almost same design as K2K) ～4200 nm int./22.5kt/yr ne:0.8% yet to be optimized

  14. Target : Cu 1cmf x 30cm Horn : 250kA Decay Pipe : 155m x 1.5mf Dipole : 50cm(V)x70cm(H)x2m(L) 0.58T (10deg@2GeV/c) Gcalor Narrow Band Beam ～830 nm int./22.5kt/yr ne:0.8%(0.3% @ peak) yet to be optimized

  15. Far Det. q Decay Pipe Horns Target Off Axis Beam (another NBB option) (ref.: BNL-E889 Proposal) WBB w/ intentionally misaligned beam line from det. axis 2° ～2200 int./22.5kt/yr ne: 0.8% (0.2% @ peak)

  16. 4. Physics Sensitivity • First 1 year WBB  pin down Dm232 to ±10% level • 5year NBB or OAB  precise measurement of q23 and q13. Sensitivity (goal): dsin22q23 ～ 0.01 sin22q13 ～ 5×10-3 (90% CL) dDm232～ 1.5×10-4eV2 at (sin22q=1.0, Dm2=3.2×10-3eV2)

  17. nm disappearance 1ring FC m-like Total Inelastic Reconstructed En (MeV) Ratio after BG subtraction. Fit with 1-sin22q・sin2(1.27Dm2L/E)

  18. 1year precision WBB NBB d(sin22q)～0.01 in 5 years

  19. Preliminary 5 2 ne appearance Background rejection against NC p0 is improved. sin22qme=0.05 WBB Dm2 CHOOZ ×10 improvement NBB OAB 3 5 sin22qme ×10-3 Dashed lines: MINOS Ph2le, Ph2me, Ph2he from right (A.Para, hep-ph/0005012)

  20. nt confirmation • NC p0 interaction • n + N →n + N + p0 • nm→ ne CC + NC(~0.5CC) ~0 (sin22qme~0) nm CC + NC(~0.5CC) ~0 (maximum oscillation)nt NC #p0 is sensitive to nt flux. Limit on the existence of sterile n.

  21. JHF-n v.s. other LBL experiment • MINOS at FNAL • similar statistics for oscillated n. • no direct t observation. • OPERA/ICANOE at CERN and Gran Sasso • less statistics for oscillated n. • Direct t observation, but t→enn is possible background to search for nm→ ne • JHF-n • will have the highest sensitivity to Dm232, q23 , q13 thanks to the gigantic SK detector and the high intensity PS.

  22. Additional Options • JHF with 1 Mton Water Cherenkov detector (for proton decay) • If nm→ ne is discovered in JHF-n, the study of CP violation becomes realistic. • #(nm→ ne )~O(100) →Asymmetry ~ 10% . →sensitivity to d ~ 10 degree. • Very LBL experiment between Japan and China (or Korea). • With a 100kt detector and a new beam line, a matter effect is measurable in nm→ ne mode. → sign of Dm232

  23. Summary and Conclusion • Neutrino Oscillation Parameters can be measured with a great precision. dsin22q23 ～ 0.01 sin22q13 ～ 5×10-3 (90% CL) dDm232～ 1.5×10-4eV2 at (sin22q=1.0, Dm2=3.2×10-3eV2) • These sensitivities are much better than other LBL program in the world.

  24. Summary and Conclusion (continue) • nm→ ne will be discovered. • GUT will be established (also with a proton decay). • CP violation in lepton sector will be seen. • Baryon number asymmetry in the universe may be understood from the CP violation in lepton sector. • Large Extra dimension may be discovered. • Or …… What do you expect?? • We need your collaboration, your cooperation and your talent. Let’s join JHF-neutrino.

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