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The Future of Neutrino Physics in a Post-MiniBooNE Era

The Future of Neutrino Physics in a Post-MiniBooNE Era. H. Ray Los Alamos National Laboratory. Outline. Introduction to neutrino oscillations LSND : The motivation for MiniBooNE MiniBooNE Overview & Current Status The Spallation Neutron Source. Standard Model of Physics. +2/3 -1/3. 0

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The Future of Neutrino Physics in a Post-MiniBooNE Era

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  1. The Future of Neutrino Physics in a Post-MiniBooNE Era H. Ray Los Alamos National Laboratory

  2. Outline • Introduction to neutrino oscillations • LSND : The motivation for MiniBooNE • MiniBooNE Overview & Current Status • The Spallation Neutron Source H. Ray

  3. Standard Model of Physics +2/3 -1/3 0 -1 0 1 H. Ray

  4. Wave-Particle Duality Flavor states are comprised of mass states m1 m2 e  ELECTRON  e H. Ray

  5. Superposition of Masses   e H. Ray

  6. Neutrino Oscillations Weak state Mass state cos  sin  e 1 =  cos  2 -sin  |(0)> = -sin  |1> + cos |2> H. Ray

  7. Neutrino Oscillations Weak state Mass state cos  sin  e 1 =  cos  2 -sin  |(t)> = -sin  |1> + cos |2> e-iE1t e-iE2t H. Ray

  8. Posc =sin22 sin2 1.27 m2 L E Neutrino Oscillations Posc = |<e | (t)>|2 H. Ray

  9. Neutrino Oscillations Distance from point of creation of neutrino beam to detection point m2 is the difference of the squared masses of the two neutrino states Posc =sin22 sin2 1.27 m2L E  Is the mixing angle E is the energy of the neutrino beam H. Ray

  10. sin22 Probability Distance from neutrino source (L) Neutrino Oscillations H. Ray

  11. Current Oscillation Status Posc =sin22 sin2 1.27 m2L E m2 = ma2 - mb2 If there are only 3 : mac2 = mab2 + mbc2 H. Ray

  12. Exploring LSND • Want the same L/E • Want higher statistics • Want different systematics • Want different signal signature and backgrounds Fit to oscillation hypothesis Backgrounds H. Ray

  13. MiniBooNE H. Ray

  14. MiniBooNE Neutrino Beam Fermilab • Start with an 8 GeV beam of protons from the booster H. Ray

  15. MiniBooNE Neutrino Beam World record for pulses pre-MB = 10M MB = 100M+ Fermilab • The proton beam enters the magnetic horn where it interacts with a Beryllium target • Focusing horn allows us to run in neutrino, anti-neutrino mode • Collected ~6x1020 POT, ~600,000  events • Running in anti- mode now, collected ~1x1020 POT H. Ray

  16. MiniBooNE Neutrino Beam Fermilab • p + Be = stream of mesons (, K) • Mesons decay into the neutrino beam seen by the detector • K+ / + + +  • + e+ +  + e H. Ray

  17. MiniBooNE Neutrino Beam Fermilab • An absorber is in place to stop muons and un-decayed mesons • Neutrino beam travels through 450 m of dirt absorber before arriving at the MiniBooNE detector H. Ray

  18. MiniBooNE Detector • 12.2 meter diameter sphere • Puremineral oil • 2 regions • Inner light-tight region, 1280 PMTs (10% coverage) • Optically isolated outer veto-region, 240 PMTs H. Ray

  19. Detecting Neutrinos • Neutrinos interact with material in the detector. It’s the outcome of these interactions that we look for H. Ray

  20. Neutrino Interactions • Elastic Scattering • Quasi-Elastic Scattering • Single Pion Production • Deep Inelastic Scattering MeV GeV H. Ray

  21. Neutrino Interactions • Target left intact • Neutrino imparts recoil energy to target Elastic Scattering Quasi-Elastic Scattering p n • Neutrino in, charged lepton out • Target changes type • Need minimum neutrino E • Need enough CM energy to make the two outgoing particles W+ e e- H. Ray

  22. Observing  Interactions • Don’t look directly for neutrinos • Look for products of neutrino interactions • Passage of charged particles through matter leaves a distinct mark • Cerenkov effect / light • Scintillation light H. Ray

  23. Cerenkov and Scintillation Light • Charged particles with a velocity greater than the speed of light * in the medium* produce an E-M shock wave • v > c/n • Similar to a sonic boom • Prompt light signature • Charged particles deposit energy in the medium • Isotropic, delayed H. Ray

  24. Event Signature H. Ray

  25. MiniBooNE • Lots of e in MiniBooNE beam vs ~no e in LSND beam • Complicated and degenerate light sources • Require excellent data to MC agreement in MiniBooNE MB :  e LSND :  e • Lots of e in MiniBooNE beam vs ~no e in LSND beam • Complicated and degenerate light sources • Require excellent data to MC agreement in MiniBooNE H. Ray

  26. Cerenkov light Scintillation light Fluorescence from Cerenkov light that is absorbed/re-emitted Reflection Tank walls, PMT faces, etc. Scattering off of mineral oil Raman, Rayleigh PMT Properties The Monte Carlo Sources of Light Tank Effects H. Ray

  27. Perfecting the Monte Carlo External Measurements and Laser Calibration Calibrate with variety of internal Physics samples Validate final Model through Data to Monte Carlo comparisons H. Ray

  28. Quasi-Elastic  Events Constrain the intrinsic e flux estimate - crucial to get right! H. Ray

  29. MiniBooNE Current Status • MiniBooNE is performing a blind analysis (closed box) • Some of the info in all of the data • All of the info in some of the data • All of the info in all of the data • MiniBooNE is performing a blind analysis (closed box) • Some of the info in all of the data • All of the info in some of the data • MiniBooNE is performing a blind analysis (closed box) • Some of the info in all of the data Public results : April 11th H. Ray

  30. Final Outcomes Confirm LSND Inconclusive Reject LSND H. Ray

  31. Final Outcomes Confirm LSND Inconclusive Reject LSND Need to determine what causes oscillations Sterile neutrinos? H. Ray

  32. Final Outcomes Confirm LSND Inconclusive Reject LSND Need to collect more data / perform a new experiment H. Ray

  33. Final Outcomes Confirm LSND Inconclusive Reject LSND Need to determine what causes oscillations Need to collect more data / perform a new experiment SNS H. Ray

  34. Final Outcomes Confirm LSND Inconclusive Reject LSND H. Ray

  35. Final Outcomes Confirm LSND Inconclusive Reject LSND SNS H. Ray

  36. All Roads Lead to the SNS Confirm LSND Inconclusive Reject LSND Need to determine what causes oscillations Need to collect more data / perform a new experiment SNS H. Ray

  37. What is the SNS? Spallation Neutron Source Accelerator based neutron source in Oak Ridge, TN H. Ray

  38. The Spallation Neutron Source Hg • 1 GeV protons • Liquid Mercury target • First use of pure mercury as a proton beam target • 60 bunches/second • Pulses 695 ns wide • LAMPF = 600 swide, • FNAL = 1600 ns wide • Neutrons freed by the spallation process are collected and guided through beam lines to various experiments Neutrinos come for free! H. Ray

  39. The Spallation Neutron Source - absorbed by target E range up to 52.8 MeV Mono-Energetic! = 29.8 MeV + DAR Target Area (Liquid Mercury (Hg+) target) H. Ray

  40. The Spallation Neutron Source • +  + +  •  = 26 ns • + e+ +  + e •  = 2.2 s • Pulse timing, beam width, lifetime of particles = excellent separation of neutrino types Simple cut on beam timing = 72% pure  H. Ray

  41. The Spallation Neutron Source • +  + +  •  = 26 ns • + e+ +  + e •  = 2.2 s SNS • Mono-energetic  • E = 29.8 MeV • , e = known distributions • end-point E = 52.8 MeV MiniBooNE H. Ray GeV

  42. The Spallation Neutron Source Neutrino spectrum in range relevant to astrophysics / supernova predictions! H. Ray

  43. Proposed Experiments Osc-SNS Sterile Neutrinos -SNS Supernova Cross Sections H. Ray

  44. Neutrino Interactions Elastic Scattering Quasi-Elastic Scattering Single Pion Production Deep Inelastic Scattering SNS Allowed Interactions MeV GeV H. Ray

  45. Neutrino Interactions @ SNS • All neutrino types may engage in elastic scattering interactions Sterile Neutrino Search H. Ray

  46. Neutrino Interactions @ SNS • All neutrino types may engage in elastic scattering interactions • Muon mass = 105.7 MeV, Electron mass = 0.511 MeV • Muon neutrinos do not have a high enough energy at the SNS to engage in quasi-elastic interactions! Sterile Neutrino Search Oscillation Search H. Ray

  47. Neutrino Interactions @ SNS • Appearance :   e • e + 12C e- + 12N • 12N 12C + e+ (~8 MeV) + e Intrinsic evs mono-energetic e from  E of e- (MeV) E of e- (MeV) H. Ray

  48. Why the SNS? Expected for LSND best fit point of : sin22 =0.004 dm2 = 1 May be < 500 ns! H. Ray

  49. Sterile Neutrinos • Sterile neutrinos = RH neutrinos, don’t interact with other matter (LH = Weak) • Use super-allowed elastic scattering interactions to search for oscillations between flavor states and sterile neutrinos • Disappearance :   e • + C  + C * • C *  C + 15.11 MeV photon • One detector : look for deficit in x events • Two detectors : compare overall x event rates H. Ray

  50. Sterile Neutrinos Near Detector only Near + Far Detector H. Ray

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