Long Baseline Neutrino Experiments Jonathan Paley, Ph.D. Indiana University Neutrinos and Dark Matter 2009 Madison, WI September 2009
Long Baseline Experiments 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E Appearance measurements (including matter effects): 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E Appearance measurements (including matter effects): ∆ = ∆ m 2 31 L sin 2 (2 θ 13 ) sin 2 ( θ 23 )sin 2 ( A − 1) ∆ P ( ν µ → ν e ) 4 E ≈ ( A − 1) 2 A = G f n e L E sin A ∆ sin( A − 1) ∆ √ ≈ +2 α sin θ 13 cos δ sin 2 θ 12 sin 2 θ 23 cos ∆ 11GeV 2 ∆ ( A − 1) A α = ∆ m 2 21 / ∆ m 2 sin A ∆ sin( A − 1) ∆ 31 − 2 α sin θ 13 sin δ sin 2 θ 12 sin 2 θ 23 sin ∆ ( A − 1) A 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E Appearance measurements (including matter effects): ∆ = ∆ m 2 31 L sin 2 (2 θ 13 ) sin 2 ( θ 23 )sin 2 ( A − 1) ∆ P ( ν µ → ν e ) 4 E ≈ ( A − 1) 2 A = G f n e L E sin A ∆ sin( A − 1) ∆ √ ≈ +2 α sin θ 13 cos δ sin 2 θ 12 sin 2 θ 23 cos ∆ 11GeV 2 ∆ ( A − 1) A α = ∆ m 2 21 / ∆ m 2 sin A ∆ sin( A − 1) ∆ 31 − 2 α sin θ 13 sin δ sin 2 θ 12 sin 2 θ 23 sin ∆ ( A − 1) A 2
Long Baseline Experiments Present day: precision neutrino oscillation measurements using a laboratory produced ~pure beam of ν µ . Disappearance measurements: � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E Appearance measurements (including matter effects): ∆ = ∆ m 2 31 L sin 2 (2 θ 13 ) sin 2 ( θ 23 )sin 2 ( A − 1) ∆ P ( ν µ → ν e ) 4 E ≈ ( A − 1) 2 A = G f n e L E sin A ∆ sin( A − 1) ∆ √ ≈ +2 α sin θ 13 cos δ sin 2 θ 12 sin 2 θ 23 cos ∆ 11GeV 2 ∆ ( A − 1) A α = ∆ m 2 21 / ∆ m 2 sin A ∆ sin( A − 1) ∆ 31 − 2 α sin θ 13 sin δ sin 2 θ 12 sin 2 θ 23 sin ∆ ( A − 1) A CERN, J-PARC and FNAL all have active LB neutrino programs; today I will focus on MINOS, T2K and NOvA. 2
The Neutrino Program at Fermilab MIPP MINOS/MINERvA/ Argoneut/NOvA MiniBooNE 3
Neutrinos at the Main Injector (NuMI) Neutrinos are produced from secondary mesons created in 120 GeV/ c p + graphite target interactions. Secondary mesons are focused by two magnetic horns; ν beam energy is tunable by moving target position longitudinally w.r.t. the horn positions. Intense source of neutrinos: ~3 x 10 13 POT ever 2.2 s ~15 ν /POT 4
MINOS - Main Injector Neutrino Oscillation Search Primary goals: Precise measurements of ∆ m 322 and sin 2 (2 θ 23 ) � � L P ( ν µ → ν µ ) ≃ 1 − sin 2 (2 θ 23 ) sin 2 1 . 27 ∆ m 2 32 E Confirm oscillations vs. other explanations (decay, decoherence) Secondary goals: Search for v µ -> v e oscillations ( θ 13 ) Measurement of ∆ m 322 and sin 2 (2 θ 23 ) for antineutrinos and other CPT tests Search for sterile neutrinos (NC events) Neutrino cross-sections 5
MINOS - The Experiment 6
MINOS - The Experiment Near Detector: 0.98 kton 1 km from target 6
MINOS - The Experiment Near Detector: Far Detector: 0.98 kton 5.4 kton 1 km from target 735 km from target 6
MINOS - The Experiment Near Detector: Far Detector: 0.98 kton 5.4 kton 1 km from target 735 km from target Both detectors are magnetic (~1.3 T) tracking calorimeters. 6
The MINOS Detectors U V U V U V U V 2.54 cm Fe Extruded PS scint. 4.1 x 1 cm 1 ” Scintillator strip Steel M16 WLS fiber Far Detector U V planes +/- 45 0 Scintillator Both detectors have: Clear Fiber cables co-extruded polysterene M64 Multi-anode PMT scintillator strips Near Detector Differences between detectors: alternating planes with orthogonal orientations PMTs & associated electronics optical fiber readout to Event rates (pileup) multi-anode PMTs Fiducial volumes (and shapes)
Identifying Events in MINOS NC event ν µ CC event ν e CC event 3.5 m 1.8 m 2.3 m Long µ track + shower Short event with Short, diffuse event. at vertex EM shower profile. E ν = E shower + E μ ,e δ E shower = 55%/ √ E δ E μ = 6% range, 10% curvature
Predicting the FD Spectrum Point Source Line Source at FD at ND Near detector spectrum is extrapolated to the far detector Use MC to provide energy smearing and acceptance corrections
MINOS Measurement of ∆ m 2 and sin 2 (2 θ ) CC/NC event separation achieved using a selection based on track length, mean pulse height, fluctuation in pulse height and transverse track profile. FD energy spectrum is only looked at after performing: low-level data quality checks procedural checks 848 events observed in the FD 1065 ± 60 expected with no oscillations We fit the energy distribution to the oscillation hypothesis. 10
MINOS Measurement of ∆ m 2 and sin 2 (2 θ ) CC/NC event separation achieved using a selection based on track length, mean pulse height, fluctuation in pulse height and transverse track profile. FD energy spectrum is only looked at after performing: low-level data quality checks procedural checks 848 events observed in the FD 1065 ± 60 expected with no oscillations We fit the energy distribution to the oscillation hypothesis. 10
MINOS ∆ m 2 and sin 2 (2 θ ) Systematics Systematic uncertainties estimated by fitting modified MC in place of data. MINOS Preliminary ν µ CC measurement is statistics-limited. Dominant uncertainties: ND/FD normalization ( ∆ m 2 ) Overall hadronic energy calibration ( ∆ m 2 ) NC background (sin 2 (2 θ ) ) MINOS Preliminary Relative These systematic normalization NC background effects are included in the final fit as nuisance Overall hadronic parameters. energy 11
MINOS ∆ m 2 and sin 2 (2 θ ) Results ∆ m 2 = (2.43 ± 0.13) x 10 -3 eV 2 (68% CL) sin 2 (2 θ ) > 0.90 (90% CL) χ 2 /ndof = 90/97 Decay Model ( V. Barget et. al. , PRL82:2640 (1999) ) disfavored at 3.7 σ Decoherence Model ( G.L. Fogli, et. al. , PRD67:093006 (2003) ) disfavored at 5.7 σ 12
MINOS Antineutrino Analysis MINOS is unique in its ability to separate ν µ from ν µ events. Do ν µ and ν µ oscillate the same way? Test of CPT. Do ν µ oscillate to ν µ ? Possible via some exotic beyond-SM processes and/or Majorana nature of neutrinos. NuMI beam consists of ~7% ν µ . Most ν µ are higher energy and come from low p T π - ’s that travel straight through the focusing horns; all other π - ’s are defocused and don’t reach the decay pipe. 13
MINOS Antineutrino Analysis MINOS is unique in its ability to separate ν µ from ν µ events. Do ν µ and ν µ oscillate the same way? Test of CPT. Do ν µ oscillate to ν µ ? Possible via some exotic beyond-SM processes and/or Majorana nature of neutrinos. NuMI beam consists of ~7% ν µ . Most ν µ are higher energy and come from low p T π - ’s that travel straight through the focusing horns; all other π - ’s are defocused and don’t reach the decay pipe. 13
MINOS Antineutrino Results Events are selected based on track length, pulse height fraction in track, pulse height per plane, track fit charge sign significance, and track curvature. Observe 42 events in the FD Predicted w/ CPT conserving oscillations: 58.3 ±7 .6 (stat) ±3.6 (syst.) Predicted w/ no oscillations: 64.6 ± 8.0 (stat) ± 3.9 (syst.) 14
MINOS Antineutrino Results MINOS excludes at maximal mixing:(5.0 < ∆ m 2 < 81)x10 -3 eV 2 (90% CL) Null oscillation hypothesis excluded at 99%. CPT conserving point from ν µ analysis falls within 90% contour. Events are selected based on track length, pulse height fraction in track, pulse height per plane, track fit charge sign significance, and track curvature. Observe 42 events in the FD Predicted w/ CPT conserving oscillations: 58.3 ±7 .6 (stat) ±3.6 (syst.) Predicted w/ no oscillations: 64.6 ± 8.0 (stat) ± 3.9 (syst.) 14
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