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Fermilab, May, 2003 Takaaki Kajita, ICRR, U. Tokyo. The JHF-Kamioka neutrino project. Outline. ・ Introduction ・ JHF-Kamioka neutrino project -overview- ・ Physics in phase-I ・ Phase-II ・ Summary. Introduction. SK atmospheric neutrino data.
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Fermilab, May, 2003 Takaaki Kajita, ICRR, U. Tokyo The JHF-Kamioka neutrino project Outline ・ Introduction ・ JHF-Kamioka neutrino project -overview- ・ Physics in phase-I ・ Phase-II ・ Summary
SK atmospheric neutrino data 1489day FC+PC data + 1678day upward going muon data 1-ring e-like 1-ring μ-like multi-ring μ-like up-going μ • Whole SK-1 data have been analyzed. stopping < 1.3GeV No osc. Through going Osc. > 1.3GeV Up-goingDown-going
Oscillation parameters νμ→ντ90%C.L. Limit on θ13 Kamiokande Soudan-2 SK MACRO
K2K 250km En En
Normalized by area (single ring events) Best fit No osc. Data: 1999 – July 2001 K2K data and oscillation NSK (# of event) 56 events observed 80.1+6.2/-5.4 ev. expt’d null oscillation prob. 1.3% + Best fit point (sin22q , Dm2) =(1.0, 2.8x10-3eV2) Consistent with SK atm.
Next: MINOS (end of 2004): Detail study of oscillations. CNGS (OPERA, ICARUS) (2006) : τ appearance. Next2: JHF-Kamioka neutrino project
JHF-Kamioka neutrino project -overview-
Main goals Main physics goals in JHF-I neutrino exp. ★Precise determination of neutrino oscillation parameters. Accuracy: sin22θ ・・・・・・ 1% Δm2・・・・・・・・・・ a few % ★Discovery and measurement of non-zero θ sin22θ ・・・・・・ > 0.01 23 13 13 Main physics goal in JHF-II ★Discovery and measurement of non-zero CP phase
JHF-Kamioka neutrino project –overview- < 1 GeV νμ beam 0.75 MW 50 GeV PS 50 kton Water Cherenkov Future Future ~1Mt “Hyper Kamiokande” 4MW 50GeV PS
Present collaboration UK Poland France Switzerland Italy Spain Korea Japan China Russia Canada USA
J-PARC(JHF) Facility Construction 2001~2006 (approved) nbeam-line + detectors budget request will be submitted soon. (0.75MW) To SK Near detectors (280m,2km)
Primary proton beamline –Overview- 50GeV PS Preparation section Normal conducting Arc R=105m Super conducting Dipole + Quadrapole combined function magnet • Single turn fast extraction • 8 bunches/~5ms • 3.3x1014proton/pulse • 3.64 sec cycle • 1yr≡1021proton on target(POT) Final Focusing Section Normal conducting
q Decay Pipe Horns Target The beam: Off axis beam 2.5±0.5゜ (ref.: BNL-E889 Proposal) 800 CC νμ/ year Eπ vs. Eν 2200 CC νμ/ year OA1° 0.0゜ Eν OA2° 1.0゜ OA3° 1.5゜ 2.0゜ 3.0゜ 5.0゜ Eπ Max. osc. energy for 3×10-3eV2
Degree w/ 1pulse R beam Target and horns (preliminary design) Target: Graphite (φ=25-30mm) w/ water cooling Temperature rise due to radiation 320kA Horn 320kA 320kA 1.5m 0.5m 2.0m 3.5m 2.5m Need much more detailed studies
Decay tunnel design 130 meters
Decay pipe cooling and heat simulation Non-static heat simulation 0.5yr@4MW, 0.5yr no beam Upto 30yrs Max @ 29.5yr Iron part Max 54o Concrete Max 121o
Detector system p p n 0m 140m 280m 2 km 295 km ν μ ν SK Near detector @2km (@50m underground) Muon detector Water Cherenkov detector Fine grained scintillater detector 8m ν beam 8m 15.2m 5m Total mass : 1000ton Fid. Mass : 100ton
Event rate & Far/near ratio 2 6 /100ton/spill @280m @280m 2 Not a good place…. 1 (φfar / φnear)×(Lfar / Lnear) 0 @2km 0.1 /100ton/spill @2km OK ! 1 Distance from target (km) Water Cherenkov : Impossible @280m (Total mass > 100 tons) 0 0 1 2 3 Eν(GeV)
Surface building φ17m 55m deep Water Cherenkov Fine grained detector Kamioka Muon detector 37m long Near detector @1.84km Candidate site (Owner: Tokai-village (local government))
m- nm+n→m + p (Em, pm) qm n p Reconstruction of Eν For single Ch ring events: Eμ, θμ Eν Super-K w/ JHF beam Quasi-elastic JHF Eν Non-QE
Normalized by area (single ring events) Best fit No osc. Quasi-elastic and other interactions High Eν non-quasi-elastic interactions cause problems. Minimize the high energy (above the max. osc. energy) neutrino flux.
Single ring (muon-like) in Super-K Data sample: SK Monte Carlo, Fully-contained single-ring, muon-like events. π π Event fraction Typical JHF neutrino energy Important to run the experiment with low energy beam.
2 2 For sin 2θ23=1.00 QE + non-QE Non-QE No osc. QE events only Oscillation (sin 2θ23=1.00) 2 2 δ(sin 2θ23) = 1% δ(Δm2) = 1×10-4eV2 Measurement of sin 2θ23 (OA 2deg) OA 3deg 1 % OA 2deg 2 4 ×10-3eV2
OA 2deg, 90%CL 4.0 3.8 Very preliminary, unofficial Only 5% normalization error considered for systematics Only look at the sensitivity on sin22θ No copy Δm2 (×10-3 eV2) 3.6 3.4 3.2 3.0 2.8 2.6 0.97 0.98 0.99 1.0 sin22θ Δm2 dependence of the sensitivity Off-axis angle should be adjusted to about 0.1 deg.
Present status: θ13 Allowed Signal for non-zero θ13 in JHF-SK (νμ→νe) BG (NC π0 ….)
νe beam contamination OAB (2degree) nm 0.2% m-decay ne K-decay νe/νμratio=0.2% at the spectrum peak.
Number of signal events and BG Dm2=3x10-3eV2, sin22q13=0.1 OAB 2deg., 5yrs
e/π0 separation • Shower direction w.r.t. beam (1) cosqne: p0 tend to have a forward peak • Force to find 2nd ring and… (2) E(g2)/E(g1+g2): Large for BG (3) Likelihood diff. between 1 and 2-ring assumptions (4) Invariant mass: Small for ne (1) (2) (3) (4) Select BG νe
Measurement of sin22θ13 Δm2 JHF sensitivity Expected signal for CHOOZ limit ×1/20 OA 2deg 5yrs sin22θ13 2
JHF Phase-II ★0.77 → 4 MW beam power ★~1 Mton detector (Hyper-Kamiokande) 106 events CP Violation
Assumptions (unless otherwise stated) Solid line: w/ matter Dashed line: w/o matter
nm beam 3.4yr νμ = 1yr νμ NCC(Number of CC events) nm beam right sign wrong sign Neutrino and anti-neutrino runs 1021pot/yr (1st phase) Important to understand the wrong sign contamination
Expected CP violation signal(1) sin22q13=0.1 Dm31<0 3s stat only 3s stat+2% syst. # of e+ events including BG 90%C.L. stat only 90%C.L. stat+2% syst. Dm31>0 CP phase # of e- events including BG
Expected CP violation signal (2) sin22q13=0.01 Dm31<0 3s stat only 3s stat+2% syst. # of e+ events including BG 90%C.L. stat only 90%C.L. stat+2% syst. Dm31>0 CP phase # of e- events including BG
3σ CP sensitivity CHOOZ excluded sin22q13<0.12@Dm312~3x10-3eV2 sin22θ13 stat+5%syst. stat+2%syst. (signal+BG) stat only stat+10%syst. no BG signal stat only JHF-I: No indication for sin22θ13 sinδ 3s CP sensitivity : |d|>20o for sin22q13>0.01 with 2% syst.
Beam eye North-south Decay pipe Candidate place About 500 – 600 m. Decay Pipe Common for SK/HK Possible site for Hyper-K SK ~8 km Beam center HK Common off-axis angle (2-3 degrees) for both Super-K and Hyper-K
Summary ● Main goals of JHF-Kamioka neutrino project (Phase-I) ★Precise determination of neutrino oscillation parameters. Accuracy: sin22θ ・・・・・・ 1% Δm2・・・・・・・・・・ a few % ★Discovery and measurement of non-zero θ13 sin22θ ・・・・・・ > 0.01 ● Main goals of JHF-Kamioka neutrino project (Phase-II) ★Discovery and measurement of non-zero CP phase ● Design works are in progress hoping to start the experiment by (the end of 2007 or) early 2008. 23 13