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θ 23 - experiments

θ 23 - experiments. Introduction Atmospheric neutrinos Super Kamiokande Soudan2 Macro Long Baseline, accelerator K2K Minos CNGS Numi Off-axis JHF Summary. Neutrino Oscillations. Weak  Mass eigenstates. where. i.e. Majorana => 2 extra phases, α 1 , α 2. m 3. Δ m 2 13. m 2.

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θ 23 - experiments

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  1. θ23 - experiments • Introduction • Atmospheric neutrinos • Super Kamiokande • Soudan2 • Macro • Long Baseline, accelerator • K2K • Minos • CNGS • Numi Off-axis • JHF • Summary G.F. Pearce

  2. Neutrino Oscillations Weak  Mass eigenstates where i.e. Majorana => 2 extra phases, α1, α2 G.F. Pearce

  3. m3 Δm213 m2 Δm213 m1 Oscillation Probabilities Probability that νaof energy Eν oscillates to νb over a path length L is e.g. Are the differences in m2 between the mass eigenstates where Ignoring CP violation and matter effects, yields 9 probabilities etc G.F. Pearce

  4. Oscillation Analyses Atmospheric analyses mostly perform a 2 ν oscillation analysis From the evidence we know atmospheric oscillations are νμ-> ντ and θ13 is small so this is a good approximation. Strictly, need to perform a 3 ν oscillation analysis to extract θ23. Such analyses are starting to be used – basically to get at θ13 G.F. Pearce

  5. Atmospheric Neutrinos Mean Eν ~ 1GeV 10 < L< 13000 km 0.5 < Δm2 < 10-4 eV2 G.F. Pearce

  6. Super Kamiokande Kamioka Mine, Japan 2700mwe overburden 50kton water Cerenkov (32kton inner, 18kton outer) 22.5 kton fiducial volume 1489 day exposure 11,146 PMTs (inner) 1885 PMTs (outer) The dominant detector in this field! G.F. Pearce

  7. SuperK ν events Good particle ID (muon-like, electron-like) Fully contained νe , νμ ~ 2 GeV Partially contained νe , νμ (primarily νμ) ~ 10 GeV Upward going stopping μ ~ 10 GeV Upward through going μ ~ 100 GeV ν detection 4 event types G.F. Pearce

  8. SuperK Event Summary G.F. Pearce

  9. νμ - ντ oscillation Null hypothesis SuperK Zenith Angle Distributions νe νμ G.F. Pearce

  10. SuperK νμ - ντ fits No oscillations fit χ2min= 465.5/170 d.o.f νμ - ντ oscillation fit 90% C.L. 1.6 10-3 < Δm2 < 3.0 10-3 eV2 sin22θ > 0.92 Best Fit Δm2 = 2.5 10-3 eV2 sin22θ = 1.0 χ2min= 163.2/170 d.o.f G.F. Pearce

  11. m3 Δm223 m2 Δm212 m1 SuperK 3-flavour oscillation analysis Assuming Δm212=Δm2sol<< Δm223 ,Δm213 Neutrino oscillation probabilities are: Fit the data to 3 parameters: Δm223,θ23,θ13 G.F. Pearce

  12. SuperK 3-flavour oscillation analysis Best fit sin2θ23 = 1.0 G.F. Pearce

  13. Soudan2 2100 mwe underground in Soudan Mine, Minnesota 963 ton modular fine grained tracking calorimeter with active shield High resolution – picture quality events Complementary to SuperK Data taking ended June 2001 5.9 fiducial kiloton-years exposure G.F. Pearce

  14. Soudan2 Neutrino Events High resolution reconstruction Fully (FCE) and Partially (PCE) contained events used in the analysis HiRes sample used for L/E analysis G.F. Pearce

  15. L/E for e and µ flavour events Unoscill. MC Best Fit MC e µ No oscillations Best fit Soudan2 L/E νμ data from two data samples PCE FCE HiRes Maximal oscillations G.F. Pearce

  16. Δm2 = 5.2 10-3 eV2 sin2 2θ = 0.97 A = 89% of Bartol 96 (Analysis with Battistoni (3D) flux yields very similar contours with A=1.05) Best Fit Soudan2 Oscillation Parameters(Feldman-Cousins Analysis) Likelihood fit to Δm2 ,sin2 2θ Confidence level contours 95% 90% 68% Log10 Δm2 (eV2) sin2 2θ G.F. Pearce

  17. MACROGran Sasso Laboratory, Italy 5.3 kton detector, High acceptance 500ps timing, 1° angular resolution E from multiple scattering, dE/dX νμ events & upward μ’s - νμ detection only G.F. Pearce

  18. L/E distribution good fit to oscillation hypothesis MACROResults MACRO - Limits on Δm2 , sin22θ Super-Kamiokande Soudan Macro HE MACRO LE G.F. Pearce

  19. Super-Kamiokande Soudan Macro HE MACRO LE Log10 Δm2 (eV2) Atmospheric LimitsSummary (SuperK) Best Fit Δm2 = 2.5 10-3 eV2 sin22θ = 1.0 G.F. Pearce

  20. K2KThe first long baseline experiment 12 GeV PS @ KEK, 5.1019 pot Eν ~ 1.3 GeV, 99% νμ 250 km Far Detector – Super Kamiokande Near Detector(s) at KEK 250km baseline Measure νμ reduction, spectrum distortion G.F. Pearce

  21. K2KNear Detector(s) Accurate measurement of beam flux and composition G.F. Pearce

  22. GPS Observe 56 Expect 80 Fully Contained Events in Fiducial Volume +7.3 - 8.0 TOF=0.83ms Tspill TSK Number of Events Spectral Shape K2K Events Beam events in SK cleanly identified Atmospheric BG < 10-3 events Oscillation Analysis Fit to G.F. Pearce

  23. K2K Limits Allowed region P(no oscillations) = 1% 90% CL Δm2 = 1.5-3.9 10-3 eV2 at sin22θ = 1.0 Best Fit Parameters Δm2 = 2.8 10-3 eV2 sin22θ = 1.0 G.F. Pearce

  24. MINOS High intensity νμ beam from Fermilab to Soudan (Mn) 120GeV p, 4.1013 ppp, 4.1020 p/yr, 1.9s rep, 8μs spill Flexible beam – adjustable energy spectrum Two detectors, Near (1kT) and Far (5.4kT) Calibration detector (mini-minos) @ CERN 735.3 km baseline 1 km wide at soudan G.F. Pearce

  25. nm CC Events/MINOS/2 year Low Medium High 5,080 13,800 29,600 Beam Energy Spectra _ _ Both nm and nm beams - nm later running MINOS Beam NUMI beam a feature of Minos Tune beam spectrum by moving 2nd horn relative to target First beam, Dec 2004 G.F. Pearce

  26. MINOS Detectors nm nm nm Minos Far Detector Site: Soudan, Minnesota, 735km Magnetised, tracking calorimeter. B ~ 1.3T 2 Supermodules, 484 planes, 5.4 kton 2.5cm thick steel, 4x1 cm scint. strips Software triggering (flexible) GPS to synch ND/FD data Veto shield (top/sides) being installed Installation complete, May/June 2003 Data taking since ~ Sep 2001 Minos Near Detector Site: Fermilab, ~ 1km Small Far detector 1kton , 153 planes ~ 1km away Pre-assembly at FNAL ready for installation High n rate, ~ 50/spill Prospects for non-oscillation n physics Installation complete ~ Oct 2004 G.F. Pearce

  27. Photo by Jerry Meier MINOS Far DetectorInstallation complete May/June 2003 shaft Soudan 2/CDMS II MINOS G.F. Pearce

  28. sin22θ MINOSOscillation parameter measurement - nm disappearance CC Energy Distributions nm CC events Reconstruct nm energy Compare Near (no osc.) with Far energy spectrum sin22θ , Δm2 measurement from oscillation minimum unoscillated oscillated Δm2 G.F. Pearce

  29. MINOSSensitivity from nm disappearance These plots are for a 10 kton-year exposure G.F. Pearce

  30. FC + PC events, 5 years SK MinosA word on atmospheric neutrinos Preliminary Data taking with Minos FD now Night/Weekend running during installation Shield (top/sides) being installed Atmospheric analysis under way Magnetic field – separation of μ+ , μ- 90% CL sin22θ Not dramatic measurement But … Interesting measurement is comparison between neutrino / anti-neutrino Assumes Super-K value of Δm2, sin22θ Fit to L/E (shape+norm) Minos reconstruction software (prelim) G.F. Pearce

  31. CERN to Gran Sasso (CNGS) νμ from CERN to Gran Sasso Baseline = 732 km 400GeV SPS protons 7.6 1019 pot/year <Eν> = 17 GeV Optimised for ντ appearance Beam by 3rd quarter 2006 Aimed at ντ, νe appearance Experiments OPERA ICARUS n flux @ Gran Sasso G.F. Pearce

  32. m spectrometer Magnetised Iron Dipoles Drift tubes and RPCs brick (56 Pb/Em. “cells”) n ~ 10 m 8 cm (10X0) module n target and t decay detector Each “super-module” is a sequence of 31 “modules” consisting of - a “wall” of Pb/emulsion “bricks” - planes of orthogonal scintillator strips brick wall scintillator strips OPERA ExperimentBriefly Lead-emulsion bricks Aim: τ appearance super module 1.77 kton 206336 bricks G.F. Pearce

  33. 90 % CL limits * m2 ( 10-3 eV2 ) 1.5 3.2 5.0 Upper limit 2.1 3.8 5.6 Lower limit 0.8 2.6 4.3(U - L) / (2*True)41 % 19 % 12 % Nτ / year 0.822.82 3.66 OPERA 90 % CL in 5 years OPERA sensitivity * assuming the observation of a number of events corresponding to those expected for the given m2 Probability to observe SuperK signal Very little (no) information on sin22θ G.F. Pearce

  34. ICARUS ExperimentBriefly Liquid Argon TPC Bubble chamber like 3D imaging Absolute timing and trigger from LAr scintillation light Ambitious, multi-purpose detector G.F. Pearce

  35. 1 3 2 Drift coord. (m) Full 2D View from the Collection Wire Plane Wire coord. (m) 2 2 4 6 12 18 1 El.m. shower 2 Zoom views m stop and decay in e Detail of a long (14 m) m track with d-ray spots 3 El.m. shower T600 test @ Pv: Run 201 - Evt 12 ICARUSThat Event G.F. Pearce

  36. ICARUSSensitivity Atmospheric Beam νμ- ντ νμ- ντ G.F. Pearce

  37. Off Axis ExperimentsNumi NUMI beam at an off-axis site New off-axis detector under design (some assumptions made in this plot) Primary Aim : θ13 measurement See talk by Alfons Weber at this meeting for details on Numi off-axis project Comparison to Minos capability 90% CL Sensitivity to Δm2similar to Minos Sensitivity to θ23 a little better Bernstein (hep-ex/0212042) G.F. Pearce

  38. 0.75MW 50 GeV PS 4MW 50GeV PS Off Axis ExperimentsJHF - Overview Aim for precision measurement of Δm223,θ23 NB θ13 !! Conventional νμ beam of ~ 1GeV Super-K: 50 kt This project and θ13 covered in detail later by Dave Wark Hyper-K: 1Mt G.F. Pearce

  39. νμ disappearance d(sin22q23) OAB, 2º d(Dm232 ) True Dm232 (eV2) JHFSensitivity to Δm223,θ23 Phase I, 5 year run d(Dm232 ) ~ < 1·10-4 (~4%) d(sin22q23) ~ 0.01 (~1%) G.F. Pearce

  40. Dreaming of ….. • Very long baseline projects • Japan – China • Brookhaven – S. Dakota/Soudan/….. • . . . . . . . . • Neutrino Factory • Focus on q13 , CP violation and high precision measurements • Not discussed here G.F. Pearce

  41. Summary • Clear effect in atmospheric neutrinos • Observed by very different experiments in different locations • νμ - ντ oscillation supported by first long baseline expt (K2K) • Physics is being measured! • Best parameter measurement is currently from SuperK • sin22θ > 0.92 @ 90% CL. Best Fit Value sin22θ =1. • Precision confirmation and improved measurements with controlled beam over next few years (Minos) • JHF + 5 years => measurement at ~ 1% • Far Future – very long baseline, neutrino factory in design, R&D phase • θ23 is close to maximal. How close? Why? Is it actually л/4 ! G.F. Pearce

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