Future Prospect of Accelerator-based Neutrino Oscillation Experimentsand other next generation experiments Two of the essential gradients of lepto-genesis CP violation D(B-L) 0 Majorana
3 ‘slits’ interferometer- possibility of CP violation in nm→ne Interferences n3 n1 n2 n3 n2 n1 ne 3 ‘slits’ Dm2~3 x 10-3 n3 n2 n1 ne nm Interference Comparable amplitudes • anti-n ? ne solar,Kamland Dm2~8 x 10-5 production detection
Importance of nm → n e Appearanced : CP Violation in Lepton Sector in 3 generations scheme ne disappearance 1- Pee : a=b |Uai| 2 Real nmne at Dm2 ~ 3 x 10-3 eV2：interference of two Dm2’s →( small Ue3 small Dm122 ) Two comparable terms → CPV CPV sinq12sinq23sinq13Dm212(L/E) sind Solar and Atmospheric n Solar LMA solution→ (large q12, relatively large Dm212) Near max. mixing in atmospheric (q23~p/4)
13withreactorexperiments • <E> ~a few MeV Disappearance • P(ee) = 1- sin2213・sin2(1.27m231L/E) + O(m221/m231) • Almost pure measurement of q13 with negligible matter effect. Searches for non-zero q13 13withacceleratorexperiments • <E> ~ O(GeV) appearance experiments • P(me) = 1- sin2q23・sin2213・sin2(1.27m231L/E) + many terms • Appearance measurement of q13. • P(nmne) also depends on d and mass hierarchy.
Reactor q13 exp. (2007) approved Double Chooz Daya bay Reno 1st generation: sin2(213)~0.02-0.03 Angra 2nd generation: sin2(213)~0.01 2006 Current Proposals on Reactor Experiments • Acc LBL exp. and Reactor q13exp. are complementary. • Appearance signal versus Disappearance signal. • Statistics Limited versus Systematic Limited • Large CPV effect versus Pure q13 effect. • Similar Time scale (~2010)
3-flavor Oscillation (simplified) m3 Oscillation Probabilities when m2 m1 • q23 :nmdisappearance • q13:neappearance common
CP d -d, a -a for nmne ne appearance probability at L/E ~ 103 (km/GeV) q13 CP conserving solar n matter effect mass hierarchy Sij=sinqij, Cij=cosqij • Small numbers • S13 • sinΦ21~ 0.03
nm → ne Appearance Measurements • L/E~3 x 102 (km/GeV) • Three contributions 1Term which is same for neutrinos and anti-neutrinos 2CP violating term (constant in E) 3Matter effect ( proportional to L or E at constant L/E) • It is almost impossible to change distance or neutrino energy To get 2+3 • Compare Neutrinos and Anti-neutrinos • Compare with reactor data CPV Make matter effect small (where 2 >3) Low energy and relatively short distance Mass hierarchy Compare with higher energy measurements 3
sin22q13=0.01 total q13 CP CP solar nmne oscillation probability in sub-GeV neutrinos Depends on many parameters matter
Accelerator NeutrinosNear future T2K Nova
T2K Collaboration • 12 Countries • Canada, France, Germany, Italy, Japan • Korea, Poland, Russia, Spain, • Switzerland, UK, USA 60 Institutes, 300 Ph.D. members Still growing Proposed in 2000, budget approved in 2004
Non-zero mass of neutrinos ! Flavor Physics esp. history of neutrino studies show full of surprises ( Kamiokande for Kamioka Nucleon decay Experiment ! ) • Emphasis lepton ID and the determination of En • En and Detector technology • 1. Look for un-expectedinprecision measurements of oscillation • parameters • 3 generation frame-work (paradigm) ? • Consistency of Dm2 in disappearance and appearance processes • Sub-process of flavor changing process ( in addition to oscillation)? • Oscillation pattern • 2. ne appearance • The last mixing to be found • q23~45oq12~34o, test q13to 3o • Determine future direction of neutrino experiment • Lead to only one practically possible test of CPV in leptons • Complex phase in mixing in light neutrinos → leptogenesis?
Main features of T2K The distance (295km) and Dm2 (~2.5x10-3 eV2 ) • Oscillation max. at sub-GeV neutrino energy • sub-GeV means QE dominant • Event-by event En reconstruction • Small high energy tail • small BKG in ne search and En reconstruction • Proper coverage of near detector(s) • Cross section ambiguity • Analysis of water Cherenkov detector data has accumulated almost twenty years of experience • K2K has demonstrated BG rejection in ne search • Realistic systematic errors and how to improve • Accumulation of technologies on high power beam
Super-K. q Decay Pipe Target Horns Narrow intense beam: Off-axis beam 振動確率＠ Dm2=3x10-3eV2 Anti-neutrinos by reversing Horn current OA0° nm flux p decay Kinematics OA2° OA2.5° 0° OA3° En (GeV) 1 2° 2.5° 3° 0 8 5 Statistics at SK (OAB 2.5 deg, 1 yr, 22.5 kt) ~ 2200nmtot ~ 1600nmCC ne~0.4% atnmpeak 0 2 pp (GeV/c) • Quasi Monochromatic Beam • Tuned at oscillation maximum • Far/near ‘simpler’ to evaluate
m- nm+ n→ m+ p (Em, pm) qm n p nm+ n→ m+ p+ p m- (Em, pm) qm n p p’s n nm+ n→ n+ p+ p’s n p p’s Quasi-Elastic process dE ~ 60 MeV dE/E ~ 10% QE inelastic CC 1p En (reconstructed) – En (true) NC 1p
e-like m-like m e PID in SK
ne appearance : q13 at Off axis 2 deg, 5 years CHOOZ excluded Dm2 Off axis 2 deg, 5 years sin22q13>0.006 sin22q13
Sensitivity to q13 as a fuction of CP-phase d d d KASKA 90% (NuFact04) KASKA 90% (NuFact04) sin22q13 d →- for n →anti-n
Disappearance En reconstruction resolution • Good resolution of En determination is critical to observe depth of the dip (measure of sin22q) dE~60MeV <10% meaurement non-QE resolution QE inelastic 1-sin22q En (reconstructed) – En (true) Dm2 + 10% bin High resolution : less sensitive to systematics
Precision measurement of q23 , Dm223possible systematic errors and phase-1 stat. • Systematic errors • normalization (10%（5%(K2K)) • non-qe/qe ratio (20% (to be measured)) • E scale (4% (K2K 2%)) • Spectrum shape (Fluka/MARS →(Near D.)) • Spectrum width (10%) OA2.5o d(sin22q23)~0.01 d(Dm223) <1×10-4 eV2
T2K Physics Sensitivity nm disappearance ne appearance (Strong d dependence) (OA2.5) Stat. only --68%CL --90%CL --99%CL Daya Bay 90% (NuFact04) CHOOZ 90% Goal d(sin22q23)~0.01 (0.08 MINOS EPS2007) d(Dm232)~<5×10-5 eV2 sin22q13 >10 times improvement from CHOOZ Neutrino ↔ Anti-neutrino, Reactor
J-PARC Facility 500 m Neutrino to Kamiokande 3 GeV Synchrotron (25 Hz, 1MW) 50 GeV Synchrotron (0.75 MW) Linac (350m) Hadron Beam Facility Materials and Life Science Experimental Facility Nuclear Transmutation J-PARC = Japan Proton Accelerator Research Complex Joint Project between KEK and JAERI
From Linac to 3 GeV From 3 GeV to Materials and Life 3 GeV Extraction Point Middle of Linac Tunnel Neutrino Tunnel 50 GeV Tunnel Upstream of Linac Tunnel JPARC Tunnel Tour
The Neutrino Beam-Line Target-Horn System Target Station Muon Monitoring Pit Final Focusing Section 295km to Super-Kamiokande Preparation Section 100m SCFM at ARC Section Beam Dump Decay Volume Near Neutrino Detector 28
~6000 ID PMTs were produced from 2002 to 2005 and were mounted from Oct.2005 to Apr.2006. Full Reconstruction (October 2005 – April 2006) All those PMTs were packed in acryic and FRP cases. Mount PMTs on a floating floor. Pure water was supplied and SK-III data taking has been running since July 11, 2006.
Schedule of T2K 2004 2005 2006 2007 2008 2009 • Possible upgrade in future • 4MW Super-J-PARC + Hyper-K ( 1Mt water Cherenkov) • CP violation in lepton sector • Proton Decay K2K T2K construction April 2009 n commissioning Linac SK full rebuild MR
Next stepMany possibilities Intensity Upgrade of MR R/D for upgrade/replacement of SK with a new hyper massive detector
CP Asymmetry cross section, detection efficiencies ratios for e/m differences in neutrino and anti-neutrino Studied by T.Kobayashi
Rate for nm is factor ~3 smaller than anti-nm due to cross section. Contamination of wrong sign components nm beam nm beam right sign wrong sign
CP asymmetry in T2K d=p/4 q12=p/8 Both correction need to be estimated at ~10% level matter F, s, e Pure CPV F,s,e cor. ACP~Aobs-0.04+0.1 matter corr.
Proton decay • e+π0 • νK+ • and other modes Reach:tp(e+p0)/B 1035 yr tp(nK+)/B 1034 yr Water Cherenkov Detector 2nd Phase (201x~?) Hyper-Kamiokande(~540kt) 1st Phase (2009~, ≥5yrs) Super-Kamiokande(22.5kt)
4MW, 540kt 2yr for nm 6~7yr for nm Sensitivity for CPV in T2K-II CHOOZ excluded sin22q13<0.12@Dm312~3x10-3eV2 Dm212=6.9x10-5eV2 Dm322=2.8x10-3eV2 q12=0.594 q23=p/4 stat+5%syst. stat+2%syst. (signal+BG) stat only stat+10%syst. no BG signal stat only T2K 3s discovery T2K-I 90% 3s CP sensitivity : |d|>20o for sin22q13>0.01 with 2% syst.
Proton decay limit from Super-K ~100k ton year already Proton Decay may be there, just around the corner Ultimate GUTs phenomena 2.9x1030 yr (‘minimal’ SUSY SU(5) )
T2K to Korea ? L=1000-1200km, =1.0-4.0 Korea J-PARC hep-ph/0607255