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OPERA experiment  : Preliminary results from the 2008 run

OPERA experiment  : Preliminary results from the 2008 run. Guillaume Lutter LHEP, University of Bern on behalf of OPERA collaboration. LLWI 09 - February 17 th 2009. Motivation. Super-Kamiokande observed ν μ disappearance in atmospheric neutrinos flux

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OPERA experiment  : Preliminary results from the 2008 run

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  1. OPERA experiment : Preliminaryresultsfrom the 2008 run Guillaume Lutter LHEP, University of Bern on behalf of OPERA collaboration LLWI 09 - February 17th 2009

  2. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam

  3. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam P(t) ~sin2223cos413sin2(m223L/4E) with Δm232 = (2.43±0.13)×10-3 eV2 sin22θ23 ~1 cos 13~1

  4. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam P(t) ~sin2223cos413sin2(m223L/4E) with Δm232 = (2.43±0.13)×10-3 eV2 sin22θ23 ~1 cos 13~1 • Requirements: • Long baseline • High beam intensity (σν~ 10-40 cm2) • Low cosmic background

  5. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam P(t) ~sin2223cos413sin2(m223L/4E) with Δm232 = (2.43±0.13)×10-3 eV2 sin22θ23 ~1 cos 13~1 • Requirements: • Long baseline • High beam intensity (σν~ 10-40 cm2) • Low cosmic background • Detect short lived τ’s

  6. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam P(t) ~sin2223cos413sin2(m223L/4E) with Δm232 = (2.43±0.13)×10-3 eV2 sin22θ23 ~1 cos 13~1 • Requirements: • Long baseline • High beam intensity (σν~ 10-40 cm2) • Low cosmic background • Detect short lived τ’s • Detector needs : • High granularity • (signal selection & background reduction) • Large mass (low cross section)

  7. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam P(t) ~sin2223cos413sin2(m223L/4E) with Δm232 = (2.43±0.13)×10-3 eV2 sin22θ23 ~1 cos 13~1 • Requirements: • Long baseline • High beam intensity (σν~ 10-40 cm2) • Low cosmic background • Detect short lived τ’s • Detector needs : • High granularity • (signal selection & background reduction) • Large mass (low cross section)  Nuclear emulsions

  8. Motivation • Super-Kamiokande observed νμ disappearance in atmospheric neutrinos flux  atmospheric neutrinos oscillations hypothesis • No direct detection of neutrino oscillation in appearance mode • Purpose of the OPERA experiment : Observe ντ appearance in a pure νμ beam P(t) ~sin2223cos413sin2(m223L/4E) with Δm232 = (2.43±0.13)×10-3 eV2 sin22θ23 ~1 cos 13~1 • Requirements: • Long baseline • High beam intensity (σν~ 10-40 cm2) • Low cosmic background • Detect short lived τ’s • Detector needs : • High granularity • (signal selection & background reduction) • Large mass (low cross section) • Installed in underground laboratory  Nuclear emulsions

  9. The OPERA collaboration Brussels Bern, Zurich Annecy, Lyon, Strasbourg Dubna, Moscow (INR,LPI,ITEP,SINP MSU) Obninsk Zagreb Hamburg, Münster, Rostock Sofia Aichi, Toho Kobe, Nagoya Utsunomiya L’Aquila, Bari, Bologna, Frascati, LNGS, Napoli, Padova, Roma, Salerno Technion Haifa Gyeongsang 35 INSTITUTIONS, ~200 PHYSICISTS METU Ankara

  10. The Oscillation Project withEmulsion tRackingApparatusexperiment • CNGS (CERN to Gran Sasso) beam νμ beam tuned for the τ appearance at LNGS (730 km away from CERN) Observe ντ appearance in a pure νμ beam Mean νμ energy : 17 GeV Requested to deliver : 22.5 x 1019 pot (5 years) The OPERA detector is installed in LNGS (Italy) which is the largest underground laboratory in the world

  11. 10.2 cm 12.5 cm The Oscillation Project withEmulsion tRackingApparatusexperiment • CNGS (CERN to Gran Sasso) beam νμ beam tuned for the τ appearance at LNGS (730 km away from CERN) Observe ντ appearance in a pure νμ beam Mean νμ energy : 17 GeV Requested to deliver : 22.5 x 1019 pot (5 years) The OPERA detector is installed in LNGS (Italy) which is the largest underground laboratory in the world • The OPERA target Basic component: OPERA Brick = 57 nuclear emulsion films interleaved by 1 mm thick lead plates Emulsion Film : 2 emulsion layers (44 m thick) poured on a 205 m plastic base (δx~1 μm δθ~1 mrad) 8.3 kg 7.5 cm Plastic base

  12. 10.2 cm 12.5 cm The Oscillation Project withEmulsion tRackingApparatusexperiment • CNGS (CERN to Gran Sasso) beam νμ beam tuned for the τ appearance at LNGS (730 km away from CERN) Observe ντ appearance in a pure νμ beam Mean νμ energy : 17 GeV Requested to deliver : 22.5 x 1019 pot (5 years) The OPERA detector is installed in LNGS (Italy) which is the largest underground laboratory in the world • The OPERA target Basic component: OPERA Brick = 57 nuclear emulsion films interleaved by 1 mm thick lead plates Emulsion Film : 2 emulsion layers (44 m thick) poured on a 205 m plastic base The OPERA target is composed of 150,036 bricks Total target mass : 1.25 kt (δx~1 μm δθ~1 mrad) 8.3 kg 7.5 cm Plastic base

  13. The Oscillation Project withEmulsion tRackingApparatusexperiment • The OPERA detector 10m 10m 20m

  14. The Oscillation Project withEmulsion tRackingApparatusexperiment • The OPERA detector

  15. The Oscillation Project withEmulsion tRackingApparatusexperiment • The OPERA detector CNGS Beam

  16. The Oscillation Project withEmulsion tRackingApparatusexperiment • The OPERA detector Super Module 2 Super Module 1 CNGS Beam

  17. The Oscillation Project withEmulsion tRackingApparatusexperiment • The OPERA detector Super Module 2 Super Module 1 Scintillator strip CNGS Beam Brick • Target • ● Target : 75,018 bricks, 29 walls • ● Scintillator strips for : • Brick selection • Calorimetry

  18. The Oscillation Project withEmulsion tRackingApparatusexperiment • The OPERA detector Super Module 2 Super Module 1 CNGS Beam • Target • ● Target : 75,018 bricks, 29 walls • ● Scintillator strips for : • Brick selection • Calorimetry Muon spectrometer for momentum and charge identification of penetrating particles

  19. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer)

  20. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer) Track identified as a muon (P=3.394 GeV/c)

  21. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer) ~ 1.5 m Track identified as a muon (P=3.394 GeV/c)

  22. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer) ~ 1.5 m A brick has been selected by the BrickFinder algorithm Track identified as a muon (P=3.394 GeV/c)

  23. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer) ~ 1.5 m A brick has been selected by the BrickFinder algorithm  Brick is extracted from the detector Track identified as a muon (P=3.394 GeV/c)

  24. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer) ~ 1.5 m A brick has been selected by the BrickFinder algorithm  Brick is extracted from the detector  Brick is developed in LNGS Track identified as a muon (P=3.394 GeV/c)

  25. Event Reconstruction Electronic data (Target Tracker & Muon spectrometer) ~ 1.5 m • A brick has been selected by the BrickFinder algorithm • Brick is extracted from the detector • Brick is developed in LNGS • Brick is sent to a scanning laboratory Track identified as a muon (P=3.394 GeV/c)

  26. Nuclear fragment Nuclear fragment Muon track Nuclear fragment Emulsions Analysis Bern emulsion scanning lab. Emulsions are scanned in a fully automatic way by using microscopes. About 40 microscopes are operational in the various OPERA scanning laboratories. 300 mm

  27. Nuclear fragment Nuclear fragment Muon track Nuclear fragment Emulsions Analysis Bern emulsion scanning lab. Emulsions are scanned in a fully automatic way by using microscopes. About 40 microscopes are operational in the various OPERA scanning laboratories. 300 mm Real nm CC interaction h Predictions from electronic detectors are followed back inside the brick until tracks stop. Then a full scanning around neutrino interaction vertex is performed and the event topology and kinematics reconstructed. 2 mm muon 2 cm

  28. Charm candidate Event (real data) pl50 pl51 pl52 pl53 pl54 pl 55 pl 56 pl57 side face Clear kink topology Two EM showers pointing to the vertex Flight length 3247.2 μm kink 0.204 rad Pdaughter 3.9 (+1.7 -0.9) GeV PT 796 MeV 4x10-4% probability for a hadron re-interaction to have a PT > 600 MeV

  29. 2nd Charm candidate Event (real data) Primary interaction Decay in 3 prongs muon Three charged prongs decay Flight length :~1150 μm Angle (muon – 3 prongs decay) : ~150° Kaon decay probability : 10-4 % Hadron re-interaction probability : 1x10-5 % muon

  30. top view 3rd Charm candidate Event (real data) side view muon muon Two charged prongs decay Flight length less than 202 μm PT minimum 2.7 GeV

  31. Analysis and event reconstruction capabilities Muons produced in charged current neutrino interactions inside the OPERA target: Mean vertical angle : (3.5 ± 0.2)° [3.3° expected from the geodesy]

  32. OPERA experiment Status • May 2006: electronic detector commissioning • October 2007: pilot physics run (~40% target) 0.082x1019 pot • first 38 neutrino events in the lead/emulsion target • June 2008: OPERA detector filled and fully commissioned (~150,000 bricks) • June – November 2008 : First OPERA production run 2008 Run 1.8x1019 pot and~1700 neutrino events in the target  Expected number of IDENTIFIED charmed events in detector: 26 Expected number ofIDENTIFIED tau events : 0.6 Beginning of January 2009 • Number of developed brick : 754 • Event located : 446 • In progress : 308 • Brick finding efficiency : 75.9 % (MC predicts 72%) • Vertex finding efficiency : 84-94 % (Charged current event) (93% from MC) 71-92 % (Neutral current event) (81% from MC) Preliminary

  33. Conclusion & Perspective • With a beamintensity of 22.5 x 1019 pot, a target mass of 1300 tons and Δm223=2.5x10-3 eV2 : • ~25000 neutrino interactions • ~120 interactions • ~10 identified • < 1 background events • The OPERA experiment has started full data taking in the CNGS beam: 2008 run: ~1.8x1019 pot, ~1700 interactions in the bricks ~0.6 identifiedτ events expected Event location in progress : 446 events (beginning of january) • Detector and ancillary facilities performed extremely well • Detection efficiencies and backgrounds are being computed with real data • Interesting events have already been analyzed (Charm, Nu-e) • Forecast for 2009: 173 days of running: ~3.5x1019 pot Sufficient integrated statistics for candidate events (~2 tau events) Precise evaluation of efficiencies, backgrounds and sensitivity in 5 years

  34. FIN Event 234533895, Brick 1015221, 10/10/2008, νμCC

  35. Backup slides

  36. CNGS

  37. CNGS neutrino flux at LNGS

  38. CNGS beam (CERN Neutrino to Gran Sasso) 4.5 1019 p.o.t. /year nmFlux at Gran Sasso (given by Fluka) Number of expected events at Gran Sasso (0-100 GeV): (before reconstruction and detection efficiencies) N nm CC= 3000/yr/kton N neCC= 20 /yr/kton N nt CC= 14 /yr/kton P(nm->nt)*s(nt CC) Dm223= 2.5 10-3 eV² nm flux

  39. Tau & OPERA Performance

  40.  appearance signature .Detection of  CC interaction and direct observation of decay topology .High background rejection tdecay kink t • t-m- nt nm (17.4%) • t-e- nt ne (17.8%) • t-h-nt n(po) (49.5%) • t-p+ p- p-nt n(po)(14.5%) ~ 0.6 mm nt

  41. Discovery probability % 3 σ sensitivity 4 σ sensitivity SK 90% CL (L/E analysis) Last MINOS measurement OPERA ντ observation probability Assume 22.5x1019 pot, ~10 signal events, < 1 BG

  42. 5 years CNGS data taking • ( 4.5 1019 pot/year ) • 1.35 ktons target mass OPERA τ search sensitivity

  43. Primary lepton not identified ,e- ,e Coulombian large angle scattering of muons in Lead : Bck. to t m Charm production in CC, common to the 3 channels Good muon identification is fundamental + e+ h+ D+ Same decay topology as  Hadronic interactions in Pb: Bck. to t h or to t m (if hadron mis-identified as muon)   Expected number of background events after 5 years running with nominal beam: h h -  τsearch : Backgrounds

  44. m232 = 2.5 x 10-3 eV2 23 = 45° nominal CNGS beam 5 years 2.5x10-3 eV2 sin2(213)<0.06 13 < 7.1º   e oscillation search 90% C.L. limits on sin2(213) and 13 :

  45. OPERA

  46. Hall B ICARUS(CNGS2) BOREXINO Hall C OPERA (CNGS1) OPERA detector at LNGS (National Laboratory of Gran Sasso, Italy, 120 kms from Rome) rock thickness 1400m (3800 m.w.e.) cosmic muon flux: 1/m2/h LNGS-INFN

  47. The Oscillation Project withEmulsion tRackingApparatusexperiment Super Module 1 SM2 δx=1 cm δθ=10-20 mrad • Target and Target Tracker (6.7m)2 • ● Target : 77500 bricks, 29 walls • ● Target tracker : 31 XY doublets of 256 scintillator strips + WLS fibres + multi-anodes PMT for • Brick selection • Calorimetry Veto plane(RPC) High precision trackerInstrumented dipole magnet ● 64-fold layers of ● 1.53 T drift tubes ● 22 XY planes of Resistive Plane Chamber in both arms Muon spectrometer (8×10 m2)

  48. Divers

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