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T2K S.Mine (University of California, Irvine) for T2K collaboration

T2K S.Mine (University of California, Irvine) for T2K collaboration. Super-K: 50 kton water Cherenkov. J-PARC ~0.7 MW 40GeV PS. K. T. phase-2: Hyper-K. ~1GeV n m beam (~  100 of K2K). phase-2: ~4 MW. this talk. discovery of n m → n e appearance

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T2K S.Mine (University of California, Irvine) for T2K collaboration

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  1. T2KS.Mine (University of California, Irvine)for T2K collaboration Super-K: 50 kton water Cherenkov J-PARC ~0.7MW 40GeV PS K T phase-2: Hyper-K ~1GeV nm beam (~100 of K2K) phase-2: ~4 MW S.Mine(UCI)@PANIC(Santa Fe)

  2. this talk • discovery of nm→ne appearance • precise measurement of nm disappearance • discovery of CP violation (phase-2) • Physics goals: • Schedule: • J-PARC (~0.7MW 40GeV PS) • construction: 2001~2007 • operation: 2008~ • T2K (approved in 2003) • construction: 2004~2008 • experiment: 2009 ~ S.Mine(UCI)@PANIC(Santa Fe)

  3. T2K collaboration 12 countries ~60 institutions ~180 collaborators S.Mine(UCI)@PANIC(Santa Fe)

  4. Accelerator/Beam line status n beam decay pipe graphite target prototype superconducting magnet horn prototype J-PARC n beam line S.Mine(UCI)@PANIC(Santa Fe)

  5. Super-Kamiokande history 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 SK-III SK-I SK-II reconstruction accident plastic vessel SK-II SK-I 11,146 number of inner detector PMTs 5,182 40 % photocathode coverage 19 % S.Mine(UCI)@PANIC(Santa Fe)

  6. Super-K. q Decay Pipe Target Horns Narrow intense beam: Off-axis beam First Application (ref.: BNL-E889 Proposal) (schematic) osc. prob.@ Dm2=3x10-3eV2 p decay Kinematics OA0° nm flux OA2° 0o OA2.5° En (GeV) 2o OA3° 2.5o 3o pp (GeV/c) S.Mine(UCI)@PANIC(Santa Fe)

  7. n interaction @ SK(w/o oscillation) • 2.5o off-axis beam (40GeV) • NEUT • n int.(22.5kt/1021pot) ~ 2200(nm) • ne/nm at peak ~0.4% nm ne n int. @ SK (/50MeV/22.5kt/1021pot) 1021pot~1year neutrino energy (GeV) S.Mine(UCI)@PANIC(Santa Fe)

  8. 3 flavor oscillation (simplified) • nm disappearance • ne appearance • beam nene oscillation P(nm→ne) = sin2q23 sin22q13 sin2(1.27 Dm132L/E) in this analysis unless noted Dm122=0, Dm122<<Dm132=Dm232 Dm232=2.5x10-3eV2,q23=p/4 no matter effect CP phase d=0 S.Mine(UCI)@PANIC(Santa Fe)

  9. Selection criteria for ne appearance (SK-I detector simulator & reconstruction used) • Standard SK cuts: • Further p0 cuts: (w/o Enrec cut) • fully contained(FC) • in fiducial volume(FV), • visible energy>100MeV • single-ring • PID(e/m) • no decay-e • 0.35<Enrec<0.85GeV signal+BG total BG ne BG events/22.5kt/5x1021pot sin22q13=0.1 reconstructed energy (GeV) • cosqne<0.9 • Mgg & DL cuts of POLfit S.Mine(UCI)@PANIC(Santa Fe)

  10. POLfit (p0 fitter) force to find 2ndg-ring identify and reject asymmetric decay p0 BG in 1R-e sample POLfit standard fitter g2 g1 • input: • vertex,1st ring dir.,total Evis • output: • Mgg, DL(p0like-elike) 500MeV/c p0 MC true Pg2 = 55.5MeV/c rec.Mp0 =140.4MeV/c2 S.Mine(UCI)@PANIC(Santa Fe)

  11. Events vs. selections (events / 22.5kt / 5x1021pot) (sin22q13=0.1) S.Mine(UCI)@PANIC(Santa Fe)

  12. ne sensitivity Dm2(eV2) 90%CL DBG=10% 5x1021pot CHOOZ excluded sin22q13~0.008 @2.5x10-3eV2 sin22q13 S.Mine(UCI)@PANIC(Santa Fe)

  13. ne sensitivity as a function of CP-phase d (90%CL, 5x1021pot, DBG=10%) S.Mine(UCI)@PANIC(Santa Fe)

  14. ne sensitivity vs. exposure(dependence on background uncertainty) DBG sources: DBG=20% DBG=10% DBG=5% sin22q13 • SK itself • p0 rejection efficiency • e/m separation • decay-e • fiducial volume • energy scale • etc. • p0 production • beam ne 3s 90%CL NDs exposure (22.5kt •1021pot) S.Mine(UCI)@PANIC(Santa Fe)

  15. K2K ne search @ SK (Feldman-Cousins approach) K2K1+K2K2 DATA: FCFV 112 ev Single Ring 67 PID(e/m) 9 tight e –ID 8 Evis>100 MeV 7 No e from me 5 POLfit cut(e/p0) 1 limit sensitivity expected BG: 1.63 observed: 1 CHOOZ limit(90%) • exp’d BG:1.63 • nm int. 1.25 • beam ne 0.38 me sin22qme <0.18 @2.8x10-3eV2 S.Mine(UCI)@PANIC(Santa Fe)

  16. e/m separation @ SK S.Mine(UCI)@PANIC(Santa Fe)

  17. e/m separation @ SK atm-nDATA(1R) atm-n MC(1R) sub-GeV (Evis<1330MeV) multi-GeV (Evis>1330MeV) An experiment with test beams also confirmed PID capability: PL B374(1996)238 S.Mine(UCI)@PANIC(Santa Fe)

  18. e/p0 separation @ SK nm MC (1Re) (rejected as p0 like) 70% p0 rejection and 30% signal efficiency loss for 1R-e sample for K2K (selected) atm-n DATA(1R-e) atm-n MC(1R-e) (Evis=150-250MeV) Mgg(MeV/c2) signal ne (Dm2=2.8e-3) p0 induced event POLfit (selected) POLfit momentum of the 1st ring (MeV/c) S.Mine(UCI)@PANIC(Santa Fe)

  19. DATA MC NC p0 measurement @ K2K-1KT events background for ne search non-p0 BG s(NC1p0)/s(CCall)=0.064±0.001±0.007 (0.065 by NEUT): Phys.Lett.B619:255,2004 S.Mine(UCI)@PANIC(Santa Fe)

  20. MiniBooNE beamline SciBar Decay region MiniBooNE Detector 50 m 100 m SciBooNE (K2K-SciBar detector at FNAL Booster Neutrino Beam line) • Cross section measurements for T2K • for both neutrinos and anti-neutrinos • MiniBooNE near detector It will be proposed to FNAL soon (cheap/quick experiment) T2K SciBar at BooNE Flux (normalized by area) K2K 1 2 S.Mine(UCI)@PANIC(Santa Fe) En (GeV)

  21. ND280: Conceptual Design Report T2K neardetectors The Experimental facility at 2km is not approved yet FGD ECAL TPC UA1 Magnet Muon Ranger Water Cherenkov Lq. Ar TPC Pi-zero Detector Tracker S.Mine(UCI)@PANIC(Santa Fe)

  22. n commissioning n phys run 2009 2010 2011 2012 2013 Japanese Fiscal Year (Apr-Mar) ne sensitivity vs. calendar time(possibility of beam power upgrade) 10% syst. err assumed on BG subtraction 0.05 400MeV LINAC from FY2011 1yr = 130days 0.04 0.03 current baseline power sin22q13 sensitivity (90%CL) 0.02 0.01 0 S.Mine(UCI)@PANIC(Santa Fe)

  23. Summary • T2K is approved and the construction is on schedule • Neutrino experiment will start in 2009 • q13 sensitivity (phase-1): - the latest n MC & SK1 final tools - SK is ideal for separating m/e/p0, K2K has demonstrated background rejection in ne search - ~10times improvement from CHOOZ - background should be understood < ~10%: • Seriously considering to increase beam power reconstruction @ SK p0 production and beam ne @ NDs S.Mine(UCI)@PANIC(Santa Fe)

  24. supplement S.Mine(UCI)@PANIC(Santa Fe)

  25. S.Mine(UCI)@PANIC(Santa Fe)

  26. Phase 2 ( if q13 can be measured. ) 2nd Phase (201x~?) Hyper-Kamiokande(~1Mt) 48m × 50m ×500m, Total mass = 1 Mton nucleon decay search CP violation measurement S.Mine(UCI)@PANIC(Santa Fe)

  27. 4MW, 540kt 2yr for nm 6.8yr for nm Search for CP violation CHOOZ excluded sin22q13<0.12@Dm312~3x10-3eV2 stat+5%syst. stat+2%syst. (signal+BG) stat only stat+10%syst. no BG signal stat only T2K 3s discovery 3s CP sensitivity : |d|>20o for sin22q13>0.01 with 2% syst. S.Mine(UCI)@PANIC(Santa Fe)

  28. Signal candidate: RUN: 21858 EVENT: 2240771 Eg1: 266.7MeV Eg2: 170.8MeV qgg: 22.5 deg. Mgg: 83.1MeV/c2 Looks multi-ring event. S.Mine(UCI)@PANIC(Santa Fe)

  29. n commissioning n line const. n phys run Possibility of beam power upgrade 3 400MeV LINAC from FY2011 2 Beam Power (kW) 1 0 2008 2009 2010 2011 2012 Japanese Fiscal Year (Apr-Mar) S.Mine(UCI)@PANIC(Santa Fe)

  30. nm disappearance • ne appearance • beam ne d→-d, a→-a for anti.-n S.Mine(UCI)@PANIC(Santa Fe)

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