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The MINOS Long Baseline Neutrino Oscillation Experiment

735 km. The MINOS Long Baseline Neutrino Oscillation Experiment. Jeff Nelson William & Mary Fermilab Users’ Meeting June 6, 2007. Overview Detector & beam Oscillation analysis Neutrino time of flight What’s New? 2 nd year of running Advances Prospects. MINOS.

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The MINOS Long Baseline Neutrino Oscillation Experiment

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  1. 735 km The MINOS Long Baseline Neutrino Oscillation Experiment Jeff Nelson William & Mary Fermilab Users’ Meeting June 6, 2007

  2. Overview Detector & beam Oscillation analysis Neutrino time of flight What’s New? 2nd year of running Advances Prospects MINOS Argonne • Athens • Benedictine • Brookhaven • Caltech • Cambridge Campinas • Fermilab • College de France • Harvard • IIT • Indiana Minnesota-Twin Cities • Minnesota-Duluth • Oxford • Pittsburgh Rutherford • Sao Paulo • South Carolina • Stanford • Sussex • Texas A&M • Texas-Austin • Tufts • UCL • William & Mary • Wisconsin

  3. MINOS Physics Goals • Test the νμ→ντ oscillation hypothesis • Measure precisely |Δm232| & sin22θ23 • PRL 97, 191801 (2006) • Search for / constrain exotic phenomena • Search for νμ→νe oscillations • Compare ν, ν oscillations • CPT test • Neutrino interaction physics • Atmospheric neutrinos • PRD 75, 092003 (2007) • PRD 73, 072002 (2006) • Cosmic rays • hep-ex/0705.3815 • 10 papers to ICRC 2007 See poster by Jeff de Jong ν2 ν3 ν1 ν2 ν1 ν3 Δm232= m32 – m22 Useful Approximations νμ disappearance (2 flavors): P(νμ→νx) = 1 - sin22θ23 sin2(1.27Δm232L/E) νe appearance: P(νμ→νe) ≈ sin2θ23sin22θ13sin2(1.27Δm231L/E) where L, E are experimental parameters & θ23, θ13, Δm232 are to be determined

  4. Example of a disappearance measurement νμspectrum Monte Carlo NC background Look for a deficit of νμ events at a distance… Spectral ratio Monte Carlo Unoscillated Unoscillated Oscillated Oscillated 0.0033 eV2 NC subtracted

  5. Example of a disappearance measurement νμspectrum Monte Carlo NC background Look for a deficit of νμ events at a distance… Spectral ratio Monte Carlo Unoscillated Unoscillated Oscillated Oscillated 0.0033 eV2 NC subtracted

  6. Example of a disappearance measurement νμspectrum Monte Carlo NC background Look for a deficit of νμ events at a distance… Spectral ratio Monte Carlo Unoscillated Unoscillated Oscillated Oscillated 0.0033 eV2 NC subtracted

  7. Producing the neutrino beam (NuMI) • 120 GeV protons strike target • 10 ms pulse every ~2.4s • Typically running at 2.5e13 protons per pulse • 2 magnetic horns focus secondary π/K • π/K decays produce neutrinos • Moveable target & horn provides variable beam energy

  8. MINOS Detectors Near Detector 1 kton 3.8  4.8  15 m3 282 steel planes 153 scintillator planes Iron and Scintillator tracking calorimeters magnetized steel planes <B> = 1.2T 1×4.1 cm2 scintillator strips Multi-anode PMT readout GPS time-stamping to synchronize FD data to ND/Beam Main Injector spill times sent to the FD for a beam trigger Far Detector 5.4 kton 8  8  30 m3 484 planes

  9. A 2 GeV νμ event in the far detector < 2 PE 2 < PE < 20 PE > 20 PE Track hit Track Energy 2.04 GeV Shower energy 0.20 GeV q/p = -0.52 ± 0.03 1pe PMT cross-talk

  10. Energy spectra in ND pHE pME LE10

  11. Energy spectra in ND pHE pME LE10 Data & Nominal MC discrepancy changes energy with beam tune Suggests production of hadrons off the target is to blame

  12. Energy spectra in ND pHE pME LE10 • Took data in 6 different beam tunes (only 3 shown) • Varied the dependence on pT and x

  13. MINOS best-fit spectrum for 1.27×1020 POT Measurement errors are 1 sigma, 1 DOF See poster by Niki Saoulidou PRL 97, 191801 (2006)

  14. MINOS allowed region for 1.27×1020 POT Measurement errors are 1 sigma, 1 DOF See poster by Niki Saoulidou PRL 97, 191801 (2006)

  15. Projected MINOS sensitivity MC MC Statistical errors 90% C.L.

  16. Prospects • Neutrino time of flight • New data • 2nd year running experience • Post-shutdown intensity • Prospects for future • Advancing the oscillation analysis • Electron neutrino appearance • Neutral current • Antineutrinos • Non oscillation physics

  17. Neutrino Time of Flight(TOF) • PDG limit is • |v−c|/c < 4 × 10-5 (95% C.L.) • Exotic models predict values all the way up to this limit • Separation between the detectors • L = 734,298.6 ± 0.7 m • The TOF for a massless particle • τ = 0.002449356 s δ = -126 ± 32 (stat) ± 64 (syst.) ns (v−c)/c = [5.1 ± 2.9 (syst. + stat.)] × 10-5 (68% CL) δ (μs) hepex/0706.0437

  18. Neutrino Time of Flight (TOF) • PDG limit is • |v−c|/c < 4 × 10-5 (95% C.L.) • Exotic models predict values all the way up to this limit • Separation between the detectors • L = 734,298.6 ± 0.7 m • The TOF for a massless particle • τ = 0.002449356 s δ = -126 ± 32 (stat) ± 64 (syst.) ns (v−c)/c = [5.1 ± 2.9 (syst. + stat.)] × 10-5 (68% CL) δ (μs) hepex/0706.0437

  19. Relativistic mass measurement • Use time and energy to compute a relativistic mass limit • If the neutrino have mass mvits time of flight would be where τ is the TOF for a massless particle • We find • The limit is driven by the few points near edge • With full data MINOS dataset ~10 MeV at 99% C.L. Line = 68% C.L. Shaded = 99% C.L. hepex/0706.0437

  20. The 2nd year of MINOS running 1st year of running (published dataset) Double dataset Collected with 99.4% live time More !

  21. MI intensity improvements: slip stacking • MI currently running in “2+5” slip stacking • 2 MI bunches for pbar • 5 MI bunches for NuMI • AD demonstrated “2+9” slip stacking • 2 MI bunches for pbar • 9 MI bunches for NuMI • New record for beam in the MI set in April • 4.608×1020 POT with good transport efficiency • Beam delivery limited to 4.0x1020 POT until we have a spare target in-hand (this summer) • AD plans “2+9” as default after the shutdown

  22. How to we plan to exploit this new data? • Modeling & reconstruction • Additional data at higher energies • Updated flux model • New hadronization & intranuclear scattering models • Improved reconstruction & PID algorithms • Reduce NC systematic errors • Ongoing improvements in calibration • Working to extend the oscillation analysis to antineutrinos & higher energies MC

  23. Since initial analysis, implemented beam fitting to antineutrinos • Antineutrinos come from π- off the target • Rates shown are for normal running conditions • Simultaneous neutrino and antineutrino fit • Compared to new p+C data from CERN NA49 n Eur.Phys.J.C49:897-917,2007

  24. High energy neutrinos and kaon production • Kaons decays tend to produce higher energy neutrinos • MIPP took p+C thin target data at 120-GeV/c • MIPP took thick-target data with our NuMI target • Forthcoming pT<0.2 GeV/c K+/p+ ratio 0.2<pT<0.4 GeV/c Andre Lebedev, Harvard Ph.D., MIPP-doc-218

  25. nm → ne oscillation search P(νμ→νe) ≈ sin2θ23sin22θ13 sin2(1.27Δm231L/E) 16×1020 POT 4×1020 POT See poster by Tingjun Yang

  26. Neutral current (NC) events Tuned MC incl. systematic error • NC unaffected by νμντ oscillations • Can test for sterile neutrino contributions • Near detector NC energy spectrum • Far Detector data for this analysis is still blinded • Currently working on • Near/Far extrapolation • FD systematic error evaluation

  27. Neutrino scattering in the near detector • Intense NuMI beam • Recorded 3 ×1020 POT • 5 × 106 events in the fiducial volume • Can explore new kinematic regions • Connect to precision higher energy experiments • Some non-oscillation analyses underway • Total CC differential cross-section • Flux extraction • DIS differential cross-section • Structure functions • Quasi elastic scattering • Coherent production cross-section … MC MC • See poster by Minsuk Kim

  28. Conclusions Results from the first year of accelerator neutrino exposure • It is consistent with νμ disappearance with the following parameters • Data also used to measure the TOF and relativistic mass of neutrinos (v−c)/c = (5.1 ± 2.9) × 10-5 (68% CL, syst. + stat.) More than doubled the dataset since shutdown • Slip stacking offers the prospect of significant intensity improvements after the shutdown New analyses are underway on a number of samples

  29. MI intensity improvements with slip stacking • MI currently running in “2+5” slip stacking mode • 2 MI bunches for pbar • 5 MI bunches for NuMI • AD demonstrated “2+9” slip stacking mode • 2 MI bunches for pbar • 9 MI bunches for NuMI • New record for beam in the MI set in April • 4.608E13 POT with good transport efficiency • Beam delivery limited to 4.0E13 POT until we have a spare target in-hand (this summer) • AD plans “2+9” as default after the shutdown • The intensity to be gradually increased from 2.4E13 POT • AD continuing preparations for the MI collimator installation during the shutdown

  30. nm → ne oscillation search See poster by Tingjun Yang • Look for ne appearance • P(νμ→νe) ≈ sin2θ23 sin22θ13 sin2(1.27Δm231L/E) (plus CP violation and matter effects) • Look for events with compact shower and typical EM profile • Primary background from NC events • Matter effects alter ne yield by 20% • Reach depends strongly on POT • Far Detector data for this analysis is still blinded • 4×1020 POT - can challenge the world’s best limit (CHOOZ) • 16×1020 POT - can significantly improve limit and increase chance of discovery

  31. Neutral current (NC) events Tuned MC incl. systematic error • NC interactions • Unaffected by νμντ oscillations • Can test for sterile neutrino contributions • Large cross-section uncertainty for E ~1 GeV • Near detector NC energy spectrum • Far Detector data for this analysis is still blinded • Currently working on • Near/Far extrapolation • FD systematic error evaluation

  32. Neutrino scattering in the near detector • Intense NuMI beam offers opportunities for exploring cross-sections • Recorded 3×1020 POT • We have 5.5×106 CC interactions in the fiducial volume • Some non-oscillation analyses underway • Total CC differential cross-section • Flux extraction • DIS differential cross-section • Structure functions • Quasi elastic scattering • Coherent production cross-section • A few examples of work in progress… MC • See poster by Minsuk Kim for more

  33. Deep Inelastic Scattering MC • Largest component of the MINOS event sample • The measurement will be systematics limited • Can explore new kinematic regions • Connects to precision higher energy experiments

  34. Quasi elastic scattering(vn →μp) • The QE-enhanced sample can be used to extract the flux for MA measurement • 3×1020 POT ~ 800,000 events • Look for • Well-defined muon track • Low shower energy • Low W • Main background • Single charged pions

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