1. NEW RESULTS FROM MINOS Patricia Vahle, for the MINOS collaboration College of William and Mary

2. The MINOS Experiment P. Vahle, Neutrino 2010 2  Long base-line neutrino oscillation experiment  Neutrinos from NuMI beam line  L/E ~ 500 km/GeV  atmospheric Δm 2  Two detectors mitigate systematic effects  beam flux mis- modeling  neutrino interaction uncertainties Far Detector 735 km from Source Near Detector 1 km from Source

3. MINOS Physics Goals P. Vahle, Neutrino 2010 3  Measure ν μ disappearance as a function of energy  Δm 2 32 and sin 2 (2θ 23 )  test oscillations vs. decay/decoherence Δm 2 32 Δm 2 21

4. MINOS Physics Goals P. Vahle, Neutrino 2010 4  Measure ν μ disappearance as a function of energy  Δm 2 32 and sin 2 (2θ 23 )  test oscillations vs. decay/decoherence  Mixing to sterile neutrinos? Δm 2 32 Δm 2 21 Δm 2 14

5. MINOS Physics Goals P. Vahle, Neutrino 2010 5 Δm 2 32 Δm 2 21  Measure ν μ disappearance as a function of energy  Δm 2 32 and sin 2 (2θ 23 )  test oscillations vs. decay/decoherence  Mixing to sterile neutrinos?  Study ν μ →ν e mixing  measure θ 13

6. MINOS Physics Goals P. Vahle, Neutrino 2010 6  Measure ν μ disappearance as a function of energy  Δm 2 32 and sin 2 (2θ 23 )  look for differences between neutrino and anti-neutrinos Δm 2 32 Δm 2 21

7. MINOS Physics Goals P. Vahle, Neutrino 2010 7  Measure ν μ disappearance as a function of energy  Δm 2 32 and sin 2 (2θ 23 )  look for differences between neutrino and anti-neutrinos  More MINOS analyses:  atmospheric neutrinos (See A. Blake poster)  cross section measurements  Lorentz invariance tests  cosmic rays Δm 2 32 Δm 2 21

8. The Detectors P. Vahle, Neutrino 2010 8 1 kt Near Detector— measure beam before oscillations 5.4 kt Far Detector— look for changes in the beam relative to the Near Detector Magnetized, tracking calorimeters 735 km from source 1 km from source

9. Detector Technology P. Vahle, Neutrino 2010 9 Multi-anode PMT Extruded PS scint. 4.1 x 1 cm 2 Extruded PS scint. 4.1 x 1 cm 2 WLS fiber Clear Fiber cables Clear Fiber cables 2.54 cm Fe U V planes +/- 45 0 U V planes +/- 45 0  Tracking sampling calorimeters  steel absorber 2.54 cm thick (1.4 X 0 )  scintillator strips 4.1 cm wide (1.1 Moliere radii)  1 GeV muons penetrate 28 layers  Magnetized  muon energy from range/curvature  distinguish μ + from μ -  Functionally equivalent  same segmentation  same materials  same mean B field (1.3 T)

10. Making a neutrino beam P. Vahle, Neutrino 2010 10

11. Making a neutrino beam P. Vahle, Neutrino 2010 11  Production  bombard graphite target with 120 GeV p + from Main Injector 2 interaction lengths 310 kW typical power  produce hadrons, mostly π and K

12. Making a neutrino beam P. Vahle, Neutrino 2010 12  Focusing  hadrons focused by 2 magnetic focusing horns  sign selected hadrons forward current, (+) for standard neutrino beam runs reverse current, (–) for anti-neutrino beam

13. Making a neutrino beam P. Vahle, Neutrino 2010 13  Decay  2 m diameter decay pipe  result: wide band beam, peak determined by target/horn separation  secondary beam monitored (see L. Loiacono poster)

14. Beam Performance P. Vahle, Neutrino 2010 14 Protons per week (x10 18 ) Total Protons (x10 20 ) Date

15. Beam Performance P. Vahle, Neutrino 2010 15 10 21 POT! Protons per week (x10 18 ) Total Protons (x10 20 ) Date

16. Beam Performance P. Vahle, Neutrino 2010 16 Previously published analyses Protons per week (x10 18 ) Total Protons (x10 20 ) Date

17. Beam Performance P. Vahle, Neutrino 2010 17 Data set for today’s report Anti- neutrino running High energy running Protons per week (x10 18 ) Total Protons (x10 20 ) Date

18. e-e- CC ν e Event Events in MINOS NC Event ν P. Vahle, Neutrino 2010 18  ν μ Charged Current events:  long μ track, with hadronic activity at vertex  neutrino energy from sum of muon energy (range or curvature) and shower energy CC ν μ Event μ-μ- Depth (m) Transverse position (m) Simulated Events

19. e-e- CC ν e Event Events in MINOS NC Event ν P. Vahle, Neutrino 2010 19 CC ν μ Event μ-μ- Depth (m) Transverse position (m)  Neutral Current events:  short, diffuse shower event  shower energy from calorimetric response Simulated Events

20. e-e- CC ν e Event Events in MINOS NC Event ν P. Vahle, Neutrino 2010 20 CC ν μ Event μ-μ- Depth (m) Transverse position (m)  ν e Charged Current events:  compact shower event with an EM core  neutrino energy from calorimetric response Simulated Events

21. Near to Far P. Vahle, Neutrino 2010 21  Neutrino energy depends on angle wrt original pion direction and parent energy  higher energy pions decay further along decay pipe  angular distributions different between Near and Far FD Decay Pipe π+π+ Target ND p Far spectrum without oscillations is similar, but not identical to the Near spectrum!

22. Extrapolation P. Vahle, Neutrino 2010 22  Muon-neutrino and anti-neutrino analyses: beam matrix for FD prediction of track events  NC and electron-neutrino analyses: Far to Near spectrum ratio for FD prediction of shower events

23. Unoscillated Oscillated ν μ spectrum ν μ Disappearance P. Vahle, Neutrino 2010 23 spectrum ratio Monte Carlo (Input parameters: sin 2 2θ = 1.0, Δm 2 = 3.35x10 -3 eV 2 ) Characteristic Shape Monte Carlo

24. Unoscillated Oscillated ν μ spectrum ν μ Disappearance P. Vahle, Neutrino 2010 24 spectrum ratio Monte Carlo (Input parameters: sin 2 2θ = 1.0, Δm 2 = 3.35x10 -3 eV 2 ) Monte Carlo sin 2 (2θ)

25. Unoscillated Oscillated ν μ spectrum ν μ Disappearance P. Vahle, Neutrino 2010 25 spectrum ratio Monte Carlo (Input parameters: sin 2 2θ = 1.0, Δm 2 = 3.35x10 -3 eV 2 ) Monte Carlo Δm2Δm2

26. CC events in the Near Detector P. Vahle, Neutrino 2010 26  Show ND energy spectrum  Majority of data from low energy beam  High energy beam improves statistics in energy range above oscillation dip  Additional exposure in other configurations for commissioning and systematics studies

27. Analysis Improvements P. Vahle, Neutrino 2010 27  Since PRL 101:131802, 2008  Additional data  3.4x10 20 → 7.2x10 20 POT  Analysis improvements  updated reconstruction and simulation  new selection with increased efficiency  no charge sign cut  improved shower energy resolution  separate fits in bins of energy resolution  smaller systematic uncertainties See C. Backhouse, J. Mitchell, and J. Ratchford, M. Strait posters

28. Far Detector Energy Spectrum P. Vahle, Neutrino 2010 28 No Oscillations: 2451 Observation:1986

29. Far Detector Energy Spectrum P. Vahle, Neutrino 2010 29  Oscillations fit the data well, 66% of experiments have worse χ 2  Pure decoherence † disfavored:> 8 σ  Pure decay ‡ disfavored: > 6 σ (7.8σ if NC events included) † G.L. Fogli et al., PRD 67:093006 (2003) ‡ V. Barger et al.,PRL 82:2640 (1999)

30. Contours P. Vahle, Neutrino 2010 30  Contour includes effects of dominant systematic uncertainties  normalization  NC background  shower energy  track energy

31. Contours P. Vahle, Neutrino 2010 31  Contour includes effects of dominant systematic uncertainties  normalization  NC background  shower energy  track energy †Super-Kamiokande Collaboration (preliminary) †

32. Neutral Current Near Event Rates P. Vahle, Neutrino 2010 32  Neutral Current event rate should not change in standard 3 flavor oscillations  A deficit in the Far event rate could indicate mixing to sterile neutrinos  ν e CC events would be included in NC sample, results depend on the possibility of ν e appearance See P. Rodrigues and A. Sousa poster

33. Neutral Currents in the Far Detector P. Vahle, Neutrino 2010 33  Expect: 757 events  Observe: 802 events  No deficit of NC events no (with) ν e appearance

34. ν e Appearance P. Vahle, Neutrino 2010 34  A few percent of the missing ν μ could change into ν e depending on value of θ 13  Appearance probability additionally depends on δ CP and mass hierarchy Normal Hierarchy Inverted Hierarchy ?⇔?⇔

35. Looking for electron-neutrinos P. Vahle, Neutrino 2010 35  11 shape variables in a Neural Net (ANN)  characterize longitudinal and transverse energy deposition  Apply selection to ND data to predict background level in FD  NC, CC, beam ν e each extrapolates differently  take advantage of NuMI flexibility to separate background components ν e selected region Data  MC BG Region See R. Toner, L. Whitehead, G. Pawloski poster

36. ν e Appearance Results P. Vahle, Neutrino 2010 36  Based on ND data, expect: 49.1±7.0(stat.)±2.7(syst.)

37. ν e Appearance Results P. Vahle, Neutrino 2010 37  Based on ND data, expect: 49.1±7.0(stat.)±2.7(syst.)  Observe:54 events in the FD, a 0.7 σ excess

38. ν e Appearance Results P. Vahle, Neutrino 2010 38 arXiv:1006.0996v1 [hep-ex]

39. Making an anti-neutrino beam P. Vahle, Neutrino 2010 39 π-π- π+π+ Target Focusing Horns 2 m 675 m νμνμ νμνμ 15 m 30 m 120 GeV p’s from MI Neutrino mode Horns focus π +, K + ν μ :91.7% ν μ :7.0% ν e + ν e :1.3% Events

40. Making an anti-neutrino beam P. Vahle, Neutrino 2010 40 π-π- π+π+ Target Focusing Horns 2 m 675 m νμνμ νμνμ 15 m 30 m 120 GeV p’s from MI Anti-neutrino Mode Horns focus π -, K - enhancing the ν μ flux Neutrino mode Horns focus π +, K + ν μ :39.9% ν μ :58.1% ν e + ν e :2.0% Events ν μ :91.7% ν μ :7.0% ν e + ν e :1.3%

41. ND Anti-neutrino Data P. Vahle, Neutrino 2010 41  Focus and select positive muons  purity 94.3% after charge sign cut  purity 98% < 6GeV  Analysis proceeds as (2008) neutrino analysis  Data/MC agreement comparable to neutrino running  different average kinematic distributions  more forward muons See J. Evans, N. Devenish poster Also A. Blake poster on atmospheric neutrinos

42. ND Data P. Vahle, Neutrino 2010 42  Data/MC agreement comparable to neutrino running

43. FD Data P. Vahle, Neutrino 2010 43  No oscillation Prediction: 155  Observe: 97  No oscillations disfavored at 6.3 σ

44. FD Data P. Vahle, Neutrino 2010 44  No oscillation Prediction: 155  Observe: 97  No oscillations disfavored at 6.3 σ

45. FD Data P. Vahle, Neutrino 2010 45

46. Comparisons to Neutrinos P. Vahle, Neutrino 2010 46

47. Comparisons to Neutrinos P. Vahle, Neutrino 2010 47

48. Summary P. Vahle, Neutrino 2010 48  With 7x10 20 POT of neutrino beam, MINOS finds  muon-neutrinos disappear  NC event rate is not diminished  electron-neutrino appearance is limited  With 1.71x10 20 POT of anti- neutrino beam  muon anti-neutrinos also disappear with  we look forward to more anti- neutrino beam!

49. Backup Slides P. Vahle, Neutrino 2010 49

50. LE 10 ME HE Neutrino Spectrum P. Vahle, Neutrino 2010 50  Use flexibility of beam line to constrain hadron production, reduce uncertainties due to neutrino flux

51. Near to Far P. Vahle, Neutrino 2010 51 Far spectrum without oscillations is similar, but not identical to the Near spectrum!

52. Far/Near differences P. Vahle, Neutrino 2010 52  ν μ CC events oscillate away  Event topology  Light level differences (differences in fiber lengths)  Multiplexing in Far (8 fibers per PMT pixel)  Single ended readout in Near  PMTs (M64 in Near Detector, M16 in Far):  Different gains/front end electronics  Different crosstalk patterns  Neutrino intensity  Relative energy calibration/energy resolution Account for these lower order effects using detailed detector simulation

53. New Muon-neutrino CC Selection P. Vahle, Neutrino 2010 53

54. Shower Energy Resolution P. Vahle, Neutrino 2010 54

55. Energy Resolution Binning P. Vahle, Neutrino 2010 55

56. CC Systematic Uncertainties P. Vahle, Neutrino 2010 56  Dominant systematic uncertainties:  hadronic energy calibration  track energy calibration  NC background  relative Near to Far normalization

57. Resolution Binning P. Vahle, Neutrino 2010 57

58. Contours by Run Period P. Vahle, Neutrino 2010 58

59. Rock and Anti-fiducial Events P. Vahle, Neutrino 2010 59  Neutrinos interact in rock around detector and outside of Fiducial Region  These events double sample size, events have poorer energy resolution Combined fit coming soon

60. Fits to NC P. Vahle, Neutrino 2010 60  Fit CC/NC spectra simultaneously with a 4 th (sterile) neutrino  2 choices for 4 th mass eigenvalue  m 4 >>m 3  m 4 =m 1

61. Electron-neutrino Background Decomposition P. Vahle, Neutrino 2010 61

62. Electron-neutrino Systematics P. Vahle, Neutrino 2010 62 Stats. Err.

63. MRCC Background Rejection Check P. Vahle, Neutrino 2010 63 R Neutrino Energy: 5.3 GeV Muon Energy: 3.2 GeV Remnant Energy: 2.1 GeV ANN PID: 0.86  Mis-id rate:  pred (6.42±0.05)%  data (7.2±0.9)% ( stats error only)  Compatible at 0.86 σ Remove muons, test BG rejection on shower remnants

64. Checking Signal Efficiency P. Vahle, Neutrino 2010 64  Test beam measurements demonstrate electrons are well simulated

65. Checking Signal Efficiency P. Vahle, Neutrino 2010 65  Check electron neutrino selection efficiency by removing muons, add a simulated electron

66. P. Vahle, Neutrino 2010 66  Hadron production and cross sections conspire to change the shape and normalization of energy spectrum ~3x fewer antineutrinos for the same exposure Making an antineutrino beam

67. Anti-neutrino Selection P. Vahle, Neutrino 2010 67 μ - Not Focused Coil Hole μ + Focused Coil Hole

68. Anti-neutrino Systematics P. Vahle, Neutrino 2010 68

69. FD Anti-neutrino Data P. Vahle, Neutrino 2010 69  Vertices uniformly distributed  Track ends clustered around coil hole

70. Previous Anti-neutrino Results P. Vahle, Neutrino 2010 70  Results consistent with (less sensitive) analysis of anti- neutrinos in the neutrino beam  anti-neutrinos from unfocused beam component  mostly high energy antineutrinos  Analysis of larger exposure on going

71. Future Anti-neutrino Sensitivity P. Vahle, Neutrino 2010 71

72. Atmospheric Neutrinos P. Vahle, Neutrino 2010 72