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(Present) Accelerator Neutrino Experiments

Aug.26, 2005 Lomonosov conf @ Moscow U. (Present) Accelerator Neutrino Experiments. Contents Introduction Oscillation experiments Long baseline: K2K(final resutls) , MINOS , ( CNGS, T2K ) Short baseline: MiniBooNE Non-oscillation experiments/measurements

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(Present) Accelerator Neutrino Experiments

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  1. Aug.26, 2005 Lomonosov conf @ Moscow U. (Present) Accelerator Neutrino Experiments • Contents • Introduction • Oscillation experiments • Long baseline: K2K(final resutls), MINOS, (CNGS, T2K) • Short baseline: MiniBooNE • Non-oscillation experiments/measurements • Neutrino interactions: K2K, MiniBooNE,..(MINERnA) • DIS • Summary Takashi Kobayashi IPNS, KEK

  2. Pure(~99%) nm (nm) beam (cf. nm:ne~2:1 in atm n) ~% ne from (p)m & K decay Oscillation experiments Flavor contents after propagation  mass & mixing in lepton sector Measure nm:disappearance, look for nl≠m: Appearance Non-oscillation experiments/measurements nm+Nucleus interactions in GeV region (resonance, coherent,..)  for future precision oscillation measurements Nucleon structure with weak bosons as probes (DIS) Electroweak couplings of light quarks  sinqW (DIS) Accelerator neutrino experiments nm(nm) nl(nl) nl(nl) l-(l+) m+(-) p p+(-) Propagation W+(-)/Z0 N Production Nucleus q Detection

  3. Neutrino mixing If neutrino have finite mass, weak and mass eigenstates can differ mi: 3 masses, Dmij: 2 differences Weak Mass eigenstates Maki-Nakagawa-SakataMatrix sij=sinqij, cij=cosqij 3 mixing angles and 1 CPV phase sin22q12~0.8 (Solar) sin22q23~1 (Atm n) Reactor Long baseline experiments

  4. Signature: Decrease of original flavor (appearance of diff flavor) Spect. Distortion Osc. Max 1.27Dm232L/E=p/2 E=0.6GeV @L=250km,Dm2=0.003 Neutrino oscillation Oscillation Probability mass eigenvalues Plm≠dml ⇔ Dmij ≠0, Non-zero off-diag U In 2 flavor approximation L (km), E (GeV) Osc. Prob. 1-P(nmnt) L=250km, Dm232=3x10-3eV2 2 1 En(GeV)

  5. Long baseline osc. experiments • Evidence of n osc in Atm n at SK (1998) • First observation contradictory to SM • Small but non-zero mass!! • Large mixing!!! • 1st generation LBL experiments • Confirmation of SK atm n results • w/ different, controlled systematics • K2K (1999~2004) • MINOS (2005~) • CNGS(2006~)-OPERA/ICARUS SK Atm n result Preliminary Suzuki LP2005 Dm2 = 2.5 x 10-3 eV2, sin22q = 1.0 2.0 < Dm2 < 3.0 x 10-3 eV2, sin22q > 0.93 (90%CL)

  6. K2K experiment First long baseline(250km) neutrino experiment. nm disappearance and ne appearance 250km Pure nm beam (99%) w/ <En>~1.3GeV • 12GeV PS • nm beam • Beam monitor • Near detector 50 kton Water Cherenkov detector Experiment started in April, 1999 Terminated in November, 2004

  7. Strategy of K2K Pion monitor (PIMON) nm p+ m+ ＳＫ Target+Horn 100m ~250km 200m decay pipe MUMON ND • Predict • # of events • nmspectrum • nm @ production • Abs. norm: 1KT • spectrum:1KT&FGD Extrapolate using Far/Near spect. ratio (MC) （ＭＣ） （ＭＣ） arb. unit w/o osc. arb. unit w/ osc? （ＭＣ） measure w/ ND Confirmed by PIMON/HARP

  8. SciBar detector Oct. 2003~ Fully active fine grained scintillation tracker Good for multi track, low E thresh.  high stat n int studies Neutrino Detectors Super-Kamiokande I Inner detector 41.4m 1114620” PMTs Outer detector 18858” PMTs 39m K2K-I Near neutrino detectors From Mar.1999 ~ Jul.2001 Muon range detector K2K-II From Dec.2002 ~ Nov. 2004 Super-Kamiokande II Inner detector ~5200 PMTs with covers Outer detector :1885 PMTs

  9. Beam POT delivered K2K-I : 0.561x1020 POT K2K-II: 0.488x1020 POT 100 K2K-I K2K-II Total POT delivered Jun.1999 – Nov.2004 1.049x1020 POT Used for analysis 0.922x1020POT Delivered POT(x1018) Date 1mrad Muon direction 1mrad

  10. Near detector measurements • Normalization • Total number of events in 1kt-WC detector • 100MeV threshold • 74.9% efficiency  Over all normalization • Spectrum • Combined (1kt+Scifi+SciBar) fit of (pm, qm) distribution

  11. F/N spectrum ratio for extrapolation (F/N)K2K =0.8264x10-6 (F/N)HARP=0.8246x10-6 (-0.2%) HARP Result • Use beam MC for F/N ratio central value • Sanford-Wang model w/ Cho(CERN) data • Confirmed by in-situ PIMON & HARP measurements • Error • >1GeV: PIMON measurement error • <1GeV: Model parameter uncertainty Hadron prod meas. at CERN-PS 12.9GeV/c p on Al PIMON Result New!

  12. Observation and Expectation at SK Dominant error Far/Near +7.9evt - 7.7evt 155.9 +11.5(7.4%) - 10.2(6.5%) Norm. +7.5evt - 7.6evt • Fully Contained • Evis>30MeV • Fid. Vol (2m cut) • 0.2<Tdiff<1.3ms 112 events -1 1 Tdiff(ms) 2.8s effect to no osc. Deficit 3.1s Reconstructed En (GeV) (assuming CCQE) Sys. err on # of evts Spectrum syst. (1 ring m) (depend on the energy bin) Ring count ~3~5% Fiducial volume 2% Particle Id <1% Energy scale ~2%

  13. Allowed parameter region (#evts/spect combined) slice atsin22q = 1.0 10-2 Dm2 (eV2) 10-3 68% 90% 99% sin22q slice at2.55x10-3 (eV2) 99% 90% 68% sin22q 4.2s Confirmation of the oscillation consistent with the atmospheric neutrino oscillation Best fit value (all region) sin22q = 1.19  0.23 Dm2 = (2.55  0.40)x10-3eV2 (in physical region) sin22q = 1.0 Dm2 = (2.76  0.36)x10-3eV2 1.8810-3 Dm2 3.4810-3 eV2 (90%CL) @ sin22q=1

  14. For K2KI+II FCFV 112 ev Single Ring 67 e-like 9 Further Reduction tight e –ID 8 Evis>100 MeV 7 No e from me 5 Pi0 cut 1 Efficiency 35.7% for K2K-I 40.9% for K2K-II Candidate Electron appearance Eg1: 266.7MeV Eg2: 170.8MeV qgg: 22.5 deg. Mgg: 83.1MeV/c2 BG nm int. beam ne 1.63 ev 1.25 0.38 K2K-I 0.60% 17.1% K2K-II 0.80% 20.4%

  15. Neutral pion rejection Pi0 cut: Forced to find 2nd e/g-ring SK Atm n DATA/MC K2K-MC nm BG MC (1Re) 1 Ring electron in atm. n (150MeV<Evis<250MeV) (rejected as p0 like) 100 p0 induced event (selected) Mgg(MeV/c2) signal ne (Dm2=2.8e-3) 100 • Reject 70% of neutral pions • (efficiency loss 30%) (selected) Rec. momentum of the 1st ring (MeV/c)

  16. Limit on the oscillation parameters Expected # of electron cand. (Feldman-Cousins approach) limit sensitivity sin22qme <0.18 @2.8x10-3eV2 Expected BG: 1.63 Observed: 1 <0.16 @3x10-3 eV2 <0.25 @2x10-3 eV2 CHOOZ limit me

  17. MINOS FNAL 120GeV Main Injector  Soudan mine (735km) Horn-focused wide band nm beam Tunable nm CC int./MINOS/yr ~ 2,500 (LE beam) (magnetized)Iron-scintillator sampling calorimeter 5,400tons @ far, 980tons @ near nm disappearance Oscillatory behavior Precise determination of Dm232, q23 Wide band nm beam 20 5 30 735km Far detector

  18. (~5 yrs) aim: Dm2 < 10% beam events Sensitivity Near detector events Preliminary pHE pME LE If q13 is close to the CHOOZ limt, MINOS will see >3s effect in ~3 years of running E (GeV) Far detector events

  19. CERN 400GeV SPS  Gran Sasso nt appearance (+ ne appearance) 4.5x1019POT/yr Wide band nm beam ~2900nm CC events/kt/yr First beam to GS May 2006 Underground civil const. finished Jun.20,2003 Beam line instrumentation being installed OPERA (next next talk for detail!) t ID by decay topology (kink) Emulsion-Counter Hybrid Total mass 1700 ton For 5yrs @4.5x1019POT/yr(200d) 12.8 nt (0.8BG) for 2.4x10-3 eV2 Start in June, 2006 with 850 tons emulsion film ICARUS: Liq. Ar TPC 600ton in mine (T600). T1200 “abandoned“ by INFN CERN neutrino to Gran Sasso (CNGS) m m 300 1 1 mm mm t t n n Pb Pb Emulsion layers Emulsion layers 732km <En>=17GeV 10 20 30 En(GeV) OPERA ECC

  20. J-PARC (50 GeV/750kW PS) Construction: 2001~2007 Operation: 2008~ T2K (Approved in Dec-03) Construction: 2004~2008 Experiment: 2009 ~ Phase 1 (0.75MW + SK) nmnx disappearance Precise Dm2, sin22q nmne appearance Finite q13 ? Tokai-to-Kamioka (T2K) (~100xK2K) J-PARC@Tokai-mura (60km N.E. of KEK) Super-K 50kton Off-axis beam: Narrow intense 1600nmCC/yr/22.5kt ne ~ 0.4% at peak (2.5deg) Phase 2  4MW, Mton, CPV

  21. Construction status Graphite target prototype Superconducting combined function magnet Decay pipe installation Horn prototype Feb. 9, 2005

  22. Sensitivities ne disappearance nm disappearance (OA2.5) Stat. only --68%CL (Dln L=0.5) --90%CL (Dln L=1.36) --99%CL (Dln L=3.32) CHOOZ 90% KASKA 90% (NuFact04) Goal d(sin22q23)~0.01 d(Dm232)~<1×10-4 >10 times improvement from CHOOZ

  23. Short baseline experiment • LSND observe osc signal • LANL 800MeV/1mA p beam • m+ decay at rest in beam stop • En<53MeV, L~30m • Dm2~1eV2, sin22q~10-(2~3) • If true • 3 mass diff. (sol/atm/LSND) • >3 n’s? • Sterile? (LEP says # of light n=3) • CPV? • Mass spect different for n/anti-n? • Definite confirmation necessary • w/ different systematics  MiniBooNE ? LSND allowed

  24. MiniBooNE Primary (protons) Secondary (mesons) Tertiary (neutrinos) FNAL Booster 8GeV Sensitivity Spectrum Look for ne in nm beam at ~ GeV Beam • 8 GeV proton beam on Be target • Horn-focused wide-band beam Detector @ L~541m • 800ton of pure mineral oil • 1280 (240) PMT’s in inner(outer) region • Cherenkov and scintillation light Expected observation @ 1021pot • Signal : 300 • Background 780 (NCp0 & beam ne dominant)  e/ 0.5% 1 2 En(GeV)

  25. MiniBooNE Status • Data taking since Aug.2002 • 5.78x1020pot so far (Jun.20,2005) • >600k n interaction recorded. • Detector calibration, studies of n interactions • Signal box will be open in late 2005 Energy Calibration p0 invariant mass

  26. Non-oscillation exp’s/measurements

  27. n interaction @ ~ 1GeV • Future precision oscillation experiments • En = Several 100MeV ~ A few GeV • Neutrino interactions around ~GeV : Complicated! • CCQE: 2 body, clean energy reconstruction • CC/NC pion productions  Source of syst err/background • Deteriorate Enreconstruction • Serious background from NC p0 production important for ne appearance • Very limited data • Let’s measure!! • Players • K2K near detector • MiniBooNE • MINERnA p m K2K SciBar CCqe candidate

  28. K2K NC p0 measurement in 1kt det nm+H2ONC1p0 • Important for future ne appearance • Selection • Fully contained • 2 e-like rings • 85<Mgg<215MeV not NC1p0 =0.0640.0010.007 =0.065 (model prediction) Phys.Lett.B619:255-262,2005hep-ex/0408134

  29. K2K CC Coh. pion measurement M. Hasegawa et al., hep-ex/0506008 2track non-QE-like CC Coherent pion production (nm+A  m-+p++A) w/ SciBar det. • K2K & MiniBooNE has been observing forward (low q2) deficit • CC Coh doubted • CC Coh enhanced sample selection • 2 track • not satisfy QE kinematics (non-QE like) • 2nd track pion (not proton) • No vertex activity • qrec2<0.1(GeV/c)2 • Result • 113 event selected • BG (non CC Coh)=111.4 • Consistent w/ No CC Coh. • Upper limit (90%CL) qrec2 CC Coh enhanced sample Inconsistent w/ Rein&Sehgal model of 2.67x10-2

  30. MiniBooNE interaction measurements Require 2 decay-e signal (from m and pm) CCqe sample CC1p sample Preliminary Preliminary Single m ring

  31. MINERnA • New experiment for n int measurements in few GeV region • Active (scintillator bar) target (5.87ton) fine grained detector • Placed in front of MINOS near detector • Expected event rate • 16×1020 POT in 4 years • Fiducial Volumes 3 ton (CH), 0.6 ton C, 1 ton Fe & 1 ton Pb • 15 Million total CC events • Status • Stage 1 approval in Apr.2004 • Fermilab requested DoE funding as part of the laboratory’s FY07 program • Projected schedule • 2006 construction start • 2008 commissioning start 1.7 × 3.3 cm2 strips WLS fiber readout in center hole

  32. n Deep inelastic scattering  sin2qW • NuTeV result (2001) • Ratio of #events of NC(short) to CC(long) events for n/nbar • 3s away from SM • Still open question • NOMAD (1995-1998) is revisiting their data • CERN SPS, A few ~ 100GeV nm • Fit to sNC/sCC & CC diff s Sensitivity d(sin2qW) ~ 1%(compara. to NuTeV) Provide independent check NuTeV NOMAD 2.7ton C (1.3M nmCC) A few ton Al (1.5M nmCC)

  33. Summary • Accelerator neutrino experiments probe/provide • Properties of neutrino (mass, mixings) in osc. exp’ts • Precision measurements of nN interaction • Precision test of standard model • Oscillation experiments • Final results of the first long baseline osc exp K2K • Disapp.:1.8810-3 Dm2 3.4810-3 eV2 (90%CL) @ sin22q=1  Confirms SK results • ne app.:sin22qme <0.18 @2.8x10-3eV2 (90%CL) • MINOS/CNGS LBL experiments is (will be) online from 2005 and 2006 • MiniBooNE result is coming soon • Non-oscillation measurements/experiments • nN interactions are being studied w/ high stat for future precision LBL experiments (K2K, MiniBooNE, NOMAD, MINERnA) • NuTeV’s 3s “discrepancy” from SM still remain. NOMAD will provide independent check with comparable uncertainty • Acc n experiments have potential to provide breakthrough toward Beyond-the-SM. Many future programs planned.  Next Prof. Lindner’s talk.

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