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On-going & Near Future for q 13

On-going & Near Future for q 13

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On-going & Near Future for q 13

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  1. 111005 ICFA seminar @CERN On-going & Near Future for q13 Takashi Kobayashi KEK

  2. Contents • Introduction • T2K results and near future prospect • MINOS results • Global fit • Near future prospect in the world • Implication of large q13 on future • Summary

  3. ne nm nt 3 flavor mixing of neutrinos Flavor eigenstates Mass eigenstates m1 m2 m3 Pontecorvo-Maki-Nakagawa-Sakata Matrix (CKM matrix in lepton sector) Atm/Acc Acc/Reactor Sol/Reactor 6 independent parameters govern oscillation q12, q23, q13, d Dm122, Dm232, Dm132 Dmij=mi2-mj2 3

  4. Present knowledge (before June, 2011) ne?? Sol/Reactor n3 Atm/Acc n2 OR n1 dunkown Which?? Big diff from KM matrix

  5. Why q13 so important?nmne appearance and CPV CPV Sol term CPV effect Unknown! (sinq12~0.5, sinq23~0.7, sinq13<0.2) The size of q13 decides future direction! 5

  6. Brief history and present situation • In 1998, evidence of nm  nx (disappearance) discovered SK in atmn observation • In 1999, as a next critical step toward CPV search, importance of nmne appearance search pointed out (K.Nishikawa&Y.Totsuka) • In 2001, LoI of T2K • After 10yrs of hard work worldwide for various experiments to discover non-zero q13, now we are getting into “harvest” season • Final conclusion on q13 will come very soon (hopefully)

  7. Searches for non-zero q13 By using reactor neutrino • :<E> ~ a few MeV edisappearance • P(ee) = 1- sin2213・sin2(1.27m231L/E) + O(m221/m231) •  Almost pure measurement of q13. • Small deficit signal  systematics dominated By using accelerator neutrino • nm:<E> ~ O(GeV)  neappearance • P(me) = sin2q23・sin2213・sin2(1.27m231L/E) + many terms(incl. d) •  Appearance measurement of q13. •  Statistics limited T2K (2009~), NOvA (2014~) Double Chooz(2011~), RENO(2011~), Daya Bay(2012~) 7

  8. Tokai-to-Kamioka (T2K) long baseline neutrino oscillation experiment • Intense off-axis (2.5deg) nm beam from J-PARC MR tuned at osc. max. • Reached 145kW (~0.9x1014ppt) • Data taking Jan. 2010 ~ Mar.11, 2011 • All data (1.43e20POT) analyzed 1.43e20pot accumulated (Jan2010~Mar2011) 8

  9. PRL 107, 041801 (2011) T2K analysis results One of most critical selection criterion validated by Atm-nelike data &Atm-ndata+MC hybrid control sample • All data analysed • Event selection • Signal Efficiency = 66% • Background Rejection: • 77% for beam νe • 99% for NC • 6 candidate events remain • 1.5±0.3 BG expected • Probability to observe >=6 evts w/ sin22q13=0: 0.7% • 2.5 s excess observed

  10. PRL 107, 041801 (2011) T2K allowed regions Chooz 90%CL upper bound @dCP=0

  11. T2K&J-PARC status and plan • J-PARC has not been operated since Mar. 11, 2011 • Intensive recovery works are on-going • We will resume J-PARC operation in Dec. 2011 • First, LINAC will start operation on Dec. 12, 2011 • We plan to have >2 “cycle”(~month) beam for users within JFY2011 (by the end of Mar,2012) • In FY2012 (Apr.2012-Mar.2013) J-PARC plan to operate fully (~9month) (budget requested) • LINAC energy recovery from 181MeV to 400MeV originally scheduled in 2012 was delayed to start July 2013 • User’s needs to take longer beam after long shutdown by the earthquake • Delay of preparation caused by earthquake

  12. Prospect of beam power • Highest priority is to establish non-zero q13 and precise measurement of q13 as soon as possible • T2K is still very much statistically limited (only 2% of approved POT has been taken) • Accelerator power improvement is CRITICAL (At present 145kW) • Short term • Replacement of inj. Kicker before next beam • Addition of RF (planned) for higher rep&ppb • Higher capacity for beam loss (collimator) • Tuning of present MR power supply for higher rep rate (3.042.6  more) • High power beam study • Longer term (few yrs) toward design intensity and beyond • R&D of high gradient RF core • R&D of high rep rate MR power supply (~1Hz or more)

  13. T2K sensitivities and milestones • We have : 0.07[MWx107s] = 0.143e21 pot We aim to have • By Summer 2013: ~0.5[MWx107s] ~ 1e21pot • Conclude non-zero q13 • >5sigma for present T2K central value • Within a few yrs : ~ 1[MWx107s] ~ 2e21pot • > 3sigma for sin22q13 > 0.04 • Approved goal : 3.75[MWx107s] ~ 8e21pot • > 3sigma for sin22q13 >~ 0.02

  14. MINOS (1st gen. exp.) FNAL 120GeV Main Injector  Soudan mine (735km) Horn-focused wide band nm beam (magnetized)Iron-scintillator sampling calorimeter 5,400tons @ far, 980tons @ near Taking data >6yrs 8.2e20pot data w/ neutrino run is used for ne appearance search Far detector

  15. MINOS latest results

  16. Exclude q13=0 at more than 3s level Best fit : sin2q13=0.021  sin22q13 = 0.084 Most urgent & important task: EXPERIMENTALLY DEFINITELY conclude A global fitting G.L.Fogli, et.al, arXiv:1106.6028v1 [hep-ph]

  17. Near future prospects in the world • 1st gen LBL experiment • OPERA • Expected (6.6E19POT) • Beam ne: 48.5 • NC : 5.2 • Signal : 5.2 (sin22q13=0.1) • (No kinematical cut) • Results expected in 2012 • q13 optimized experiments • Reactor experiments • NOvA

  18. 16.1GW reactor & 2x16ton detectors (1.4km) Started data taking with both near & far detectors from Aug. 1, 2011. First results on sin2(2q13) ~0.5 are expected to be available within a half year. sin2(2q13) > 0.02 at 90% within ~3yrs RENO experiment FD ND T2K center Fogli Global fit center Co

  19. Double Chooz • 8.2GW reactor & 2x8ton detector (1.05km) • Far detector completed, started data taking since Apr. 13, 2011, >120dys w/ 75% phys data live • Data taking w/ near det expected from early 2013 • Sin22q13 sensitivity (90%CL) ~0.08 in half yr, 0.03 ultimately 4 T2K center

  20. 6x2.95=17.4GW & 4x20t far/4x20t near det’s (1.6~2km) 4/8 det’s filled, 2det’s taking data Data taking with full det’s from Summer 2012 sin22q13 <0.03(0.02) at 3s in 1(3) yrs Daya Bay experiment

  21. FNAL NuMI off-axis beam Power upgrade 320kW700kW Recycler: anti-proton  proton Rep cycle 2.2s  1.33s New 14kton liquid scintillator fine grained detector @810km Far detector will complete and start full operation in 2014 NOvA 21

  22. Can measure large q13 (~T2K center) very soon For smaller q13 good competition Have some sensitivity on mass hierarchy NOvA expected sensitivities Fogli T2K region T2K Fogli T2K

  23. Implication of large q13 on Future • If sin22q13> ~0.01 • Make conventional Multi-MW super beam long baseline experiments possible to explore CPV in lepton sector • Although big step needed • IF not • Need “ideal” beam such as Neutrino Factory or beta beam to probe CPV T2K region

  24. Implication of large q13 on Future 1st peak @ 295km (0.6GeV) • CPV asymmetry get smaller for larger q13 • Severer requirement on systematic error • Matter effect becomes comparable even at @295km •  Need energy spectrum information to disentangle CPV and Matter effect • ~20% CPV effect at sin22q13=0.1 w/ sindCP=1 (max. vio.) at 1st peak • To detect CPV >3s for sind>0.2 (Asym=4%) O(10k) events necessary • Much higher statistics is necessary  >MW proton & huge detector mandatory T2K 90% region Matter effect Pure CPV effect  Next talk

  25. Summary • Quest for non-zero q13 is turning around final corner • T2K detected first indication of ne appearance at 2.5s significance • 0.03(0.04)<sin22q13<0.28(0.34) (inv hier) • MINOS presented consistent results • New reactor experiments are getting online • NOvA will come in 2014 • Discovery of finite q13 will come very soon (hopefully)! • Large q13 makes possible to explore CPV with upgraded >MW beam and Huge high sensitivity detector