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Accelerator neutrino experiments

Accelerator neutrino experiments. Jennifer Thomas University College London. Thanks to s.brice, p.vahle, d.wark. Accelerator neutrino experiments. Direct observation of tau neutrinos DoNUT Present neutrino oscillation results k2k, minos , opera, (lsnd,mini-boone)

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Accelerator neutrino experiments

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  1. Accelerator neutrino experiments Jennifer Thomas University College London Thanks to s.brice, p.vahle, d.wark

  2. Accelerator neutrino experiments • Direct observation of tau neutrinos • DoNUT • Present neutrino oscillation results • k2k, minos, opera, (lsnd,mini-boone) • Plans for next generation long baseline experiments • Experiments of general interest • Cross sections : sci-boone, minerva • t2k, nova • conclusion J.Thomas Lepton-Photon 2007

  3. Normal hierarchy (m3)2 (m2)2 Dm221 (m1)2 ne Dm232 nm Dm231 nt (m2)2 Dm221 (m1)2 (m3)2 m2lightest m2lightest Neutrino sector status (2007) Inverted hierarchy 3light neutrino flavours: e,m,t Dm221 : (7.0 - 9.1) × 10-5 eV2 TAN2q12 : 0.34 – 0.62 Dm232 : (2.2 – 2.58) × 10-3 eV2 sin2q23 : 0.31 – 0.71 SIN2q13 ≤ 0.045 d : unknown Hierarchy : unknown mlightest < 2.2 eV Dirac or Majorana: unknown [updated from Gonzalez-Garcia PASI 2006] J.Thomas Lepton-Photon 2007

  4. DONuT: Direct Observation of • Analysis complete – 9  found in578 total  • Background ~1.5 events (charm + hadronic int) • Preliminary x-section results (cc) X relative to  e for energy-indpdt part Proof of principle for opera X  J.Thomas Lepton-Photon 2007

  5. νμ spectrum Spectrum ratio Monte Carlo Monte Carlo (m3)2 (m2)2 Dm221 Unoscillated (m1)2 ne Dm232 Oscillated nm Dm231 nt (m2)2 Dm221 (m1)2 (m3)2 m2lightest m2lightest 2-3 long baseline concept J.Thomas Lepton-Photon 2007

  6. K2K:1st long baseline experiment • Confirmation of sk result • 300m near detector • 250km baseline • SuperK far detector • 112 observed nm cc • 158.1 expected 58 single-ring m-like evts Phys.Rev.D 74, 072003,2006 L/E=0.25Km/MeV J.Thomas Lepton-Photon 2007

  7. MINOS: 2-3 sector precision measurement Far Detector: Soudan, Minnesota 5.4 kton mass 484 steel/sci planes 8x8x30 m3 2.3% absolute calibration B-field~1.3T Far detector Near Detector: Fermilab, Illinois 1km from target 1 kton mass 282 steel planes 3.1% absolute calibration 153 scintillator planes, 3.8x4.8x15 m3 Bfield~1.3T 735 km baseline l/e=0.4km/mev Near detector J.Thomas Lepton-Photon 2007

  8. Neutrinos from the Main Injector (NuMI) 2.5e20 p.o.t. Used in new analysis • 10 μs spill 120 GeV protons every 2.4s • 180 kW typical beam power • 2.5 1013 protons per pulse • Neutrino spectrum changes with target and horn position J.Thomas Lepton-Photon 2007

  9. n Calorimeter Spectrometer Fiducial Volume MINOS: near detector exploitation • ‘Identical’ Detectors ND and FD • Use ND spectra for: • Beam MC tuning => flux measurement • FD spectrum prediction takes advantage of all cancellations • Cross section • Detector thresholds • Secondary hadron production (1st order) J.Thomas Lepton-Photon 2007

  10. MINOS Beam MC tuning • Use different beam configurations to learn about beam • Discrepancies in different places pointed to beam issues • Parameterize Fluka2005 hadron production • re-weight as f(xF,pT) • Horn focusing, beam misalignments, neutrino energy scale, n cross section, NC background Weights applied vs pz & pT J.Thomas Lepton-Photon 2007

  11. minos near detectornm cc selection ParticleIDentificationDistribution CC-like NC-like All Energies Finding muons is main approach Select cc events with pdf based on 6 parameters reflecting confidence in event’s track like characteristics J.Thomas Lepton-Photon 2007

  12. MINOS FD Spectrum Prediction • Hadron production changes are 2nd order : affects ND and FD together x = Measured ND spectrum is transported to FD Efd is not just End/r2 Pion/Kaon decay kinematics encapsulated in matrix MC to provide corrections (resolution, acceptance) 6.2s effect <10GeV J.Thomas Lepton-Photon 2007

  13. Sector 2-3 allowed parameter space Statistics limited J.Thomas Lepton-Photon 2007

  14. MC MINOS MC MINOS Outlook • Muon neutrino disappearance • 6e20 pot by end 2008 • Anti-neutrino oscillations • in neutrino beam • anti-n running > 09 • Electron neutrino appearance by end 2007 • Search for exotics • Sterile neutrinos • Neutrino decay/de-coh J.Thomas Lepton-Photon 2007

  15. Opera : appearance oftau neutrinos nm nt mspectrometer: Dipolar magnet + RPC chambers • Physics goals: • Verify oscillation is to nt • Search for ne appearance • cngs L/e = 0.04km/MeV (17GeV En) • 12 events expected, 1 bkg, after 5 yrs • May 07 cosmic test: • Prediction, extraction, scanning • Turn on sep 07 50-60kbricks • Full compliment mar 08 Emulsion Cloud Chamber 1 mm t Pb J.Thomas Lepton-Photon 2007

  16. 10-2 Dm231 [eV2] (m3)2 (m2)2 Dm221 (m1)2 ne Dm232 nm Dm231 nt (m2)2 Dm221 (m1)2 (m3)2 10-3 m2lightest m2lightest sin2q13 Future long baseline : goals nmne • high precision 2-3 parameters • observation of ne events • q13 : present sin2q13<0.04 • cp violation d • mass hierarchy Schwetz hep/ph 0606060 J.Thomas Lepton-Photon 2007

  17. L(km), E(GeV), m(eV) e ne Future long baseline: goals Patmos Psolar interference • Measure q13 • present limit: • Sin22q13<0.15 • Sin2q13<0.04 • Sinq13<0.2 • q13<11.5o CP violation and matter effects are ambiguous for half possible values of d Second experiment with different l (or E) will give complimentary information for mass hierarchy ne e J.Thomas Lepton-Photon 2007

  18. Far Detector Near Detector Decay Pipe q Target Horns Future long baseline:tools Off axis beams X-sec measurements: Minerna and sci-boone • High granularity detector in NuMI beamline : good for nona • wide scope : several z x-sec measurements at a few GeV Reduces high energy tail and so NC p0 background Reduces necontamination from K and m decay due to decay kinematics • K2K SciBar detector in the FNAL Booster Neutrino Beamline • Precision measurement of x-secs for T2k : beam well matched e/gev J.Thomas Lepton-Photon 2007

  19. NOnA • Far detector: • 14 kton, fully active segmented • 14.5 mrad off NuMI beamline axis • 810 km baseline, En~2gev, l/e=0.4km/mev • Near Detector • Functionally same as FD • Will move to sample different backgrounds optical fibre J.Thomas Lepton-Photon 2007

  20. Nona: future reach • Matter effects increase (decrease) oscillations for normal (inverted) hierarchy for n • Hierarchy can be resolved if q13 near to present limit Matter effect in • Nova has longest baseline: 810km • run with n and n J.Thomas Lepton-Photon 2007

  21. T2K: jparc to Super-K Near Det @ 280m 2.5mrad(off-axis) Inside ua1/nomad magnet for momentum measurement Sandwich calorimeters/tracker for precision beam measurement En~0.8GeV, l/e=0.4km/mev p0 from neutral current interactions important background Ingrid detector @ 280m (on-axis) Iron scintillator tracker Determines beam profile and direction J.Thomas Lepton-Photon 2007

  22. T2K: Sensitivity Plot from I. Kato/T2K J.Thomas Lepton-Photon 2007

  23. T2k and nona: latest T2K: • Hoping for first data April 2009 • Ramp up to 750kW source by 2012 Nova: • Hoping to start detector construction in 2010 and have 700kW source on same timescale Many inponderables Reasonable assumptions J.Thomas Lepton-Photon 2007

  24. conclusions • A decade of discovery has produced 5 effective parameters: sin2q23,tanq12,|Dm223|,Dm221 and its sign • Lessons learned for the future • Near detector ….is your best friend! • Beam flexibility….is next • Still to be determined: q13, sign (Dm223), dCP • Maybe dCP , Dm223 within reach of next experiments if sin22q13>0.01 • Point is to find an underlying symmetry: focus on precision measurements of parameters • Near detectors • Off axis beams and flexibility • Cross sections • Detector precision J.Thomas Lepton-Photon 2007

  25. BACKUP SLIDES J.Thomas Lepton-Photon 2007

  26. MINOS Near Detector: Particle IDentification Input Variables J.Thomas Lepton-Photon 2007

  27. Improvements: • reco & selection • shower modelling • Data sets: • Pre-shutdown • Post-shutdown What Changed? J.Thomas Lepton-Photon 2007

  28. NuMI Alignment Align the center of  beam to the Far Detector in the Soudan mine. Goal is within 12 m. • Fermilab to Soudan surface done using GPS • determined vector to 0.01 m horiz., 0.06 m vertical • Soudan surface to 27th level • 0.7 m per coordinate • Fermilab surface to underground • gyrotheodolite with 0.015 mrad precision • 11 m at Soudan • Transverse alignment of baffle, target and horn at 0.5 mm J.Thomas Lepton-Photon 2007

  29. Event generator Neutrino-nucleus interactions were generated using the NEUGEN3 neutrino event generator (H. Gallagher, Nucl.Phys.Proc.Suppl. 112: 188-194, 2002) Quasi-Elastic: dipole parametrization of form factors with ma=0.99 GeV/c2 (BBBA05 Bradford et al. Nucl.Phys.Proc.Suppl.159:127-132,2006) Resonance Production: Rein-Seghal model for W<1.7 GeV/c2. (Annals Phys. 133: 79, 1981) DIS: Bodek-Yang modified LO model. For W<1.7 GeV tuned to electron and neutrino data in the resonance / DIS overlap region. (Bodek-Yang, Nucl. Phys. Proc. Suppl. 139: 113-118, 2005 and H. Gallagher, NuINT05 Proceedings) Coherent Production: Rein-Seghal (Nucl. Phys. B 223: 29, 1983) J.Thomas Lepton-Photon 2007

  30. Beam Matrix Prediction & Near Detector Data : RunI/RunIIa J.Thomas Lepton-Photon 2007

  31. Effect of MC tuning on the measurement Far Predicted Spectra using the Beam Matrix and with/without hadron production tuning Ratio of Far Prediction using the Beam Matrix and with/without hadron production tuning Using tuned MC for energy smearing and acceptance corrections Using nominal MC for energy smearing and acceptance corrections Using tuned MC for energy smearing and acceptance corrections Using nominal MC for energy smearing and acceptance corrections Using Beam Matrix Method, hadron production tuning does not affect the Unoscillated prediction (obtained from the ND data) by more than 1-2%. However, its use improves the MC (make it more similar to the data) and therefore uncertainties due to energy smearing-unsmearing and acceptance become smaller. J.Thomas Lepton-Photon 2007

  32. MINOS: new analysis 2007 New PID has higher overall efficiency and higher background rejection (less contamination from NC interactions) J.Thomas Lepton-Photon 2007

  33. MINOS: Near Detector Data/MC Event Vertices (X Y Z) normalized to area Track Angles (X Y Z) J.Thomas Lepton-Photon 2007

  34. MINOS: systematic uncertainties The main remaining systematic uncertainties are Near/Far normalization, absolute hadronic energy scale and NC contamination Overall systematics reduced by use of near detector J.Thomas Lepton-Photon 2007

  35. FD Data Expected ( Unoscillated) Data/Prediction Data Sample CClike All 563 738 30 0.76 (4.4 )  CClike (<10 GeV) 310 496 20 0.62 (6.2 ) CClike (<5 GeV) 198 350 14 0.57 (6.5  For energies between 0-10 GeV a deficit of 38% is observed, with respect to the no disappearance hypothesis. J.Thomas Lepton-Photon 2007

  36. Near and Far Detectors are functionally identical: 2.54cm thick 1.3 T magnetised steel plates co-extruded scintillator strips orthogonal orientation on alternate planes – U,V optical fibre readout to multi-anode PMTs 2.54 cm Fe Extruded PS scint. 4.1 x 1 cm WLS fiber U V planes +/- 450 Clear Fiber cables Multi-anode PMT MINOS Detector Technology Scintillator strip M16 PMT J.Thomas Lepton-Photon 2007

  37. LSND result Excess ofne events in a nmbeam 87.9 ± 22.4 ± 6.0 over background ~4s evidence foroscillation Dm2 different from the solar and atmospheric Dm2s. With 3 standard model neutrinos 2 independentDm2s could lsnd result be evidence for a sterile neutrino? Mini-boone sees no excess in nmne l/e=0.001kev/km L/E=0.001km/MeV J.Thomas Lepton-Photon 2007

  38. 0-3 GeV 3-6 GeV J.Thomas Lepton-Photon 2007

  39. After q13 P ~ (Patmos)1/2 + (Psolar)1/2 + interference terms L=735km probability E (GeV) Much information within :± Dm2,d, matter effect Effects are non-trivial to disentangle Complimentarity with different L,E and production J.Thomas Lepton-Photon 2007

  40. MINOS NC analysis : near detector Spectra Search for sterile n MC error band beam, cross-section and energy scale uncertainties Fogli et al. 3+1 model J.Thomas Lepton-Photon 2007

  41. MINOS: nmne appearance status • Using full power of the near detector • Comparison of mc/data shows discrepency • Same effect in muon removed cc sample points to shower modelling • Bkgd spectrum will be derived from nd data nm m nm Hadronic shower n J.Thomas Lepton-Photon 2007

  42. Future long baseline: tools x-sec measurements : basic foundation of n probes • CCQE x-sec is best known • search for tiny signals: background estimate is paramount • eg: high y cc events which oscillate cannot be estimated in near detector • 2 experiments being mounted to address these issues Compilation ofnmCC Quasi-Elastic x-Section Measurements J.Thomas Lepton-Photon 2007

  43. MINOS: measurement vs prediction P(c2,n.d.f) = 0.18 c2 /n.d.f = 139.2/36 =3.9 No Disappearance Hypothesis Oscillation Hypothesis best fit c2 /n.d.f = 41.2/34 = 1.2 6.2s effect below 10GeV P(2,n.d.f) = 0.18 J.Thomas Lepton-Photon 2007

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