2. 1 The OPERA Long Baseline Neutrino Experiment: status and first results Introduction Detector overview CNGS neutrino beam start-up First neutrino events and detector performances Conclusions D.Duchesneau, LAPP, Annecy for the OPERA collaboration ICHEP08 July 30 th, 2008 20 m 10 m 8 m

3. 2 European Long Base-line project: motivated by the atmospheric disappearance results CNGS/OPERA: In the CERN high energy   beam (CNGS): search for  appearance at the Gran Sasso laboratory (732 km from CERN) Answer unambiguously on the origin of the  oscillations observed at the atmospheric  m 2 scale search for   e and put new constraints on   3 ) E LΔm.(θ)νP(ν μ 2 23 2 2 271sin)2(   cos 4 θ 13 () Best fit:  m 2 = 2.39 10 -3 eV 2 and sin 2 2  = 0.995 2.06 <  m 2 < 2.81 x 10 -3 eV 2 3  range Global 3 oscillation analysis: (2008) : Ref: G.L. Fogli et al. arXiv:0805.2517v2

4. 3 Experimental signature for  appearance: detect and identify the   charged current (CC)  events  -    h -    n   e -   e  +  -  -   n    R      decay modes  e  ,e,    p,n, ,K...  Reject efficiently main topological background: charm production prompt  at primary vertex wrong sign assignment at secondary vertex pt imbalance criteria  c  < 1 mm 150 evts/kton/year OPERA Principle: direct observation of  decay topology  requires  m resolution: use photographic emulsions  needs large target mass: alternate emulsion films with lead sheets (ECC concept)  good lepton identification direct  observation by DONUT in 2000 K. Kodama, et.al., PLB 504 (2001) 218-224

5. 4 Gran Sasso National Laboratory: ( Italy, 120 km from Rome) Underground laboratory: good cosmic ray shielding 1 cosmic/m 2 /hr 3 large experimental halls (100m x 18m x 18m) directed towards CERN 1400 m OPERA ICARUS HallC Hall B Borexino 3800 mwe

6. 5 COLLABORATION 13 countries 36 institutions ~ 200 physicists Russia INR Moscow, LPI Moscow, ITEP Moscow, SIMPMSU Moscow, JINR Dubna, Obninsk Belgium IIHE(ULB-VUB) Brussels France LAPP Annecy, IPNL Lyon, IRES Strasbourg Germany Hamburg, Münster, Rostock Israel Technion Haifa Italy Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Naples, Padova, Rome, Salerno Japan Aichi, Toho, Kobe, Nagoya, Utsunomiya Switzerland Bern, Neuchâtel, ETHZ Zurich Turkey METU Ankara Korea Gyeongsang Jinju Croatia IFB Zagreb Bulgaria Sofia University  July 2000: Experiment proposal  May 2003 Start construction  Summer 2006 First run with cosmics and CNGS beam to Gran Sasso  Autumn 2007 First CNGS beam with interactions seen in emulsion target Tunisia UPNHE Tunis

7. 6 (may 2008) 1.3 kton detector at Gran Sasso (Hall C) 2 identical Super Modules (SM) SM1 SM2 Veto plane (glass RPC) Target and Target Tracker (6.7m) 2 ● Target : 77500 bricks, 26 walls ● Target tracker : 31 XY doublets of 256 scintillator strips + WLS fibres + multi- anodes PMT for Brick selection Muon tracks reconstruction High precision tracker Instrumented dipole magnet ● 6 4-fold layers of ● 1.53 T drift tubes ● 22 XY planes of RPC Muon spectrometer (8×9 m 2 ) scintillator strips brick wall module brick (56 Pb/Em. “cells”) 8 cm (10X 0 )

8. 7 OPERA target: Modular detector: basic unit brick Pb  1 mm emulsion layers (44  m thick) plastic base 200  m thick 56 Pb sheets (1mm) + 57 FUJI emulsion films +1 changeable sheet doublet 12.5cm 8cm 10cm 12.5cm 10.2cm 8.3 kg 10X 0 Track segment resolution:  (angle) = 2.1 mrad  (position) = 0.21  m 2mm 6mm Vertex position resolution : ~1µm in transverse plane The most precise tracker Electron identification, e/  separation and energy measurements for electrons and photons Neural network vs. MC 14 mm  test beam 987654321987654321 1 2 3 4 5 6 7 8 P rec (GeV) Measurement of hadrons momenta by Multiple Coulomb Scattering P beam (GeV)

9. 8 BAM (Brick Assembling Machine) Automatic lead/emulsion piling in a dark room (~700 bricks/day) 5 articulated robots Target preparation now 2003 : start building detector January 2007: start filling target July 2008 : end of filling target Insertion and extraction of bricks following complex procedures. The BMS(Brick Manipulator System) one robot on each side of the detector 146200 bricks today  1.26 kton 6 m

10. 9 CNGS: beam optimized for  appearance For 1 year of CNGS nominal operation in shared mode: For  m 2 =2.5x10 -3 eV 2 and maximal mixing expect 14  CC/kton/year at Gran Sasso  CC / kton 2900  NC / kton 875 ( GeV ) 17 ( e + e ) /  0.85 %  /  2.1 %  prompt negligible 200 days/year ;  = 80% 4.5 x 10 19 pot/year OPERA: ~ 30 evts/day “Off-peak”:   flux optimized to maximize the  charged current interactions = 43 Km/GeV

11. 10 First run with CNGS neutrinos cosmics Beam events interaction in magnet (Fe)  319 registered events correlated in time with beam : interactions inside the rock and inside the detector (TT and spectrometers) Ref: New J. Phys. 8 (2006) 303  August 2006: 7.6x10 17 integrated pot Proton extractions from SPS with 3 cycles of 6s each : 2 extractions of 10.5  s, separated by 50 ms. event selection by using GPS timing information practically no background O(10 -4 ) interaction in surrounding rock

12. 11 First CNGS run with lead-emulsion target (80% SM1 filled = 0.5 kton) 6.72 10 17 pot 5/10/07 9/10/07 ComissioningPhysics 3.91 10 17 pot 8.24 10 17 pot 20/10/07 Problems in ventilation control units of the proton target 12/10/07 5  9 : CNGS very stable at 1.58 10 17 pot/day 32  6 expected events in bricks 38 events registered during the 2007 CNGS run : 29 CC 9 NC Expected 75% CC and 25%NC proportions Time: in ns from 1/01/1970  Sept-Oct 2007: 8.24x10 17 integrated pot CNGS integrated intensity from September 24 th to October 20 th 2007:

13. 12 µ CC Hadronic shower muon µ -- n Hadronic shower P  =7.8 GeV First OPERA neutrino event located in a brick (October 2 nd 2007) 18 m 1 cm compatible  0  2  :  0 mass: 110 ± 30 MeV   e + e - Automated emulsion analysis: about 40 automatic microscopes in various labs

14. 13 µ n Hadronic shower µ µ NC Hadronic shower 18 m Nagoya scanning laboratory 2 cm 2007 CNGS neutrino event State of the art automated microscopes fast bi-dimensional image analysis real-time high precision 3D tracking

15. 14 …a charm candidate! Flight length: 3247.2 μm  kink : 0.204 rad P daughter : 3.9 (+1.7 -0.9) GeV P T : 796 MeV (> 606 MeV ) Two e. m. showers pointing to vertex 2007 CNGS neutrino event Clear kink topology + EM shower

16. 15 Analysis of the  CC events reconstructed in Europe Comparison CNGS events versus MC 5000  CC MC events simulated and reconstructed in emulsions Global analysis of 2007 neutrino events Impact parameter track  vertex Preliminary Angle of tracks wrt neutrino beam axis  3D  Preliminary Track Momentum measured by MCS Preliminary Good agreement within statistical uncertainties

17. 16 Main background sources: charm production and decays hadron re-interactions in lead large-angle muon scattering in lead OPERA with 1.35kt (75%)    search full mixing, 5 years run @ 4.5x10 19 pot / year OPERA expected signal and background 4-  evidence 3-  evidence OPERA Discovery probability vs.  m 2 0 20 40 60 80 100 Discovery probability (%) 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Minos 2008 90% CL Exclusion plot at 90% C.L. SK 90% CL (L/E analysis)

18. 17  The OPERA detector is completed and is now massive with 1.3 kton of lead- emulsion target  Emulsion scanning stations and infrastructures are ready and operational  In 2006 and 2007: cosmic runs + first CNGS neutrino runs:  Test and tuning of electronic detectors, brick finding algorithm and scanning strategy => reach the design goals  Validation of reconstruction software and analysis tools The concept of the OPERA detector has been successfully validated. Conclusions Next step: 2008 CNGS neutrino run from June to November Started since June 20 th : 160 events already in OPERA target Expect about 2.28x10 19 pot in 123 days of SPS running assuming a nominal intensity of 2x10 13 pot/extraction ~20 neutrino interactions / day  observation of the 1 st  event …  38 neutrino events have been observed in OPERA bricks during the CNGS beam run of 2007. Localization and reconstruction of neutrino vertex in emulsions was an important phase to confirm the analysis strategy.

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20. Next step: 2008 CNGS neutrino run from June to November Expect about 2.28x10 19 pot in 123 days of SPS running assuming a nominal intensity of 2x10 13 pot/extraction ~20 neutrino interactions / day  observation of the 1 st  event … CNGS actual performances: Started since June 20th : 160 events already in OPERA target and 834 events in surrounding material Integrated intensity of 1.72x10 18 pot 1.72 E 18 pot Beam loss, vacuum accident 27/6-2/7 Fri 20/6 3 cycles Unix Time pot Sat 21/6 Horn fault Wed 18/6 17:00 Start of commissi oning at low intensity MD 25/6 10/7 21:00 Earth fault on the PS magnet Long MD stop + MTE kicker problem 7/7 6:00 – 10/7 12:00 PS magnet repair 22/7 0:00   =50% including accidents and small beam interruptions  Achieved intensity = 1.6x10 13 pot/extraction 2008

21. 20 Limits at 90% CL for  m 2 = 2.5x10 -3 eV 2 full mixing 5 years: 2.25x10 20 pot syst. on the e contamination up to 5% Preliminary sin 2 2  13  m 2 23 (eV 2 ) 4.50 10 19 pot/yr 6.76 10 19 pot/yr   e expected signal and background OPERA sensitivity to  13 Ref: Komatsu et al. J. Phys. G29 (2003) 443.

22. 21 τ search : Backgrounds  -- ,e ,e - +e+h++e+h+ D+D+ Same decay topology as  Charm production in CC, common to the 3 channels Good muon identification is fundamental Primary lepton not identified Coulombian large angle scattering of muons in Lead : Bck. to     Hadronic interactions in Pb: Bck. to  h or to    if hadron mis- identified as muon) Expected number of background events after 5 years running with nominal beam: h h τeτeτμτμτhτhτ  3h Total Charm background.173.008.134.181.496 Large angle μ scattering.096 Hadronic background.077.095..172 Total per channel.173.181.229.181.764

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25. 24 Reconstruction of micro-tracks (45µm) 2D images processing 3D reconstruction of particle tracks 10 scanning laboratories in Europe and Japan: different technology 2 emulsion sides (45  m) 1 plastic base (200  m) 16 tomographic images = 45µm 300µm 300µm Field of vue Field of vue Scanning : emulsion digitisation 20÷50 cm 2 /h/side on 43  m emulsion layers 0.3÷0.7  m precision 90%÷95% track finding efficiency 10÷10 4 fake tracks / cm 2 (slope < 0.5)

26. 25 Emulsion scanning in OPERA XY stage (Micos) 0.1 μm nominal precision Z stage (Micos) 0.05 μm nominal precision Illumination system, objective (Oil 50× NA 0.85) and optical tube (Nikon) CMOS camera 1280×1024 pixel 256 gray levels 376 frames/sec (Mikrotron MC1310) Emulsion Plate The European Scanning System  Scanning speed: 20 cm 2 /h/side (40 GB/day/microscope of raw data)  Purity: 10 fake tracks / cm 2 (slope < 0.5)  Efficiency: up to 95% using tracks, ~100% using microtracks ~100% using microtracks  0.3÷0.7 μm precision for recons. tracks X axis is driven with continuous motion Custom CMOS camera 512×512 pixel 3000 frames/sec Piezoelectric fine drive for Z motion of lens Oil objective 35× NA 0.85 Mechanics based on Nikon microscope stages X/Y/Z nominal precision = 0.1mm The S-UTS (Japan)  Scanning speed: 50 cm 2 /h/side average (72 cm²/h/side peak) custom parallel processing (FPGAs) custom parallel processing (FPGAs)  Purity: 10 fake tracks / cm 2 (slope < 0.4)  Efficiency: 95% using tracks State-of-art automated microscopes fast bi-dimensional image analysis real-time high precision 3D tracking