1 Status of the OPERA long-baseline neutrino experiment Magali Besnier PIC 07- Annecy June 27 th 2007

2 Search for tau  neutrino appearance at Gran Sasso laboratory in a pure muon neutrino beam produced at CERN (732 km) First direct observation of   oscillation 37 INSTITUTS, ~160 PHYSICISTS OPERA Oscillation Project with Emulsion tRacking Apparatus International Collaboration (Europe + Japan) IIHE (ULB-VUB), Brussels Sofia IHEP Beijing, Shandong IRB Zagreb LAPP Annecy, IPNL Lyon, IRES Strasbourg Berlin Humboldt, Hagen, Hamburg, Münster, Rostock Technion Haifa Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Napoli, Padova, Roma La Sapienza, Salerno Aichi, Kobe, Nagoya, Toho, Utsunomiya INR Moscow, ITEP Moscow, JINR Dubna, Obninsk Bern, Neuchâtel, Zurich METU Ankara Possibility of  e  oscillation search for  13 measurement

3 Hadron stop Horn Civil engineering completed (June ’03) Hadron stopper and decay tube installed (June ’04) Target section completed in 2006 (first CNGS beam in August 2006) Decay tube vacuum tests successful CNGS beam (CERN Neutrino to Gran Sasso) vacuum p.o.t. /year 700 m 100 m 1000m 67 m 400GeV Ø at GS=2km 3.2° angle To Gran Sasso

4 P(   CC)  m 2 23 = eV²  Flux at Gran Sasso (given by Fluka)  flux CNGS beam (CERN Neutrino to Gran Sasso) p.o.t. /year Number of expected events at Gran Sasso (0-100 GeV): (before reconstruction and detection efficiencies) N  CC  yr/kT N e  CC  yr/kT N  CC  yr/kT.Detection of  CC interaction and direct observation of decay topology.High background rejection         (17.4%)    e -     (17.8%)    h -   n    (49.5%)           n(   ) (14.5%)    decay kink ~ 0.6 mm  appearance signature

5    oscillation OPERA Performances for    oscillation full mixing, 5 years 4.5x10 19 pot / year Number of expected signal and background events Most important background : charm particle production Best value of  m 2 23 = eV² 3  range : eV² T.Schwetz, hep-ph/

6 rock thickness 1400m (3800 m.w.e.) cosmic muon flux:  1/m 2 /h OPERA (CNGS1) ICARUS (CNGS2) Hall C Hall B BOREXINO OPERA detector at LNGS (Notional Laboratories of Gran Sasso, Italy, 120 kms from Rome)  spectrometer: Dipolar magnet + RPC chambers Target Trackers Pb/Em. target Precision tracker: Drift tubes B=1.6 T 2 super modules 1 super module = 31 walls + 31 Target Tracker + 1 muon spectrometer (21 RPC planes + 6 drift tube planes) bricks Lead target : 1.8 kTon ~6000  CC/yr 52*64 bricks/wall  p/p < 20% for E<50GeV brick (56 Pb/Em. “cells”) 8 cm (10X 0 ) scintillator strips brick wall module

7 OPERA bricks : main target detector component 2mm 6mm Emulsion Cloud Chamber (ECC) : 1 ECC brick = 56 sheets Pb + 57 photographic emulsions Pb Emulsion layers  1 mm 12 M emulsion films and 12 M thin lead foils by Fuji Film (Japan) JLGoslar (Germany) This technology allows a spatial micrometric resolution, and a 3D reconstruction of particle tracks, necessary for  detection 12.5 cm 8 cm 8.6 kg 10 cm 12.5cm 10.2cm 2 emulsion layers (44  m thick) poured on a 200  m plastic base The most precise tracker Résolution (microtracks) spatial : 0.06 µm Angular : ~ 2 mrad Vertex position resolution : ~1µm in transverse plane - Measurement of hadrons momenta by MCS - dE/dx pion/muon separation at low energy - Electron identification and energy measurements for electrons and photons Reconstructed electronic shower

8 BAM (Brick Assembling Machine) Automatic lead/emulsion piling in a dark room ( bricks/day) Insertion and extraction of bricks following intelligent procedures. The BMS(Brick Manipulator System) one robot on each side of the detector Target preparation Daily total Begining 2007 now Brick production and insertion

9 Detector today : electronics fully instrumented and tested Brick filling on the way : Bricks already inserted LNGS Hall C

bricks extracted / day selection of the interaction brick provided by time correlation of electronic detectors Emulsion Development of candidate bricks at Gran Sasso (surface facilities) Example of a vertex in emulsion Emulsion Scanning with automated microscopes : 15 laboratories in Europe and Japan Emulsion shipment OPERA event analysis procedure 0 max p.h.  Brick finding : 31 tracking scintillator planes (TT)/super modules Trigger(  >99%) + Brick finding (  70  80%) Neutrino  events in OPERA-like bricks (PEANUT test-beam) Salerno scanning lab analysis NUMI beam at low energy configuration Scanning labs performance tests and improvements with : -  /e test-beams -  test-beam -cosmic runs

11 First OPERA results with CERN neutrino beam cosmics Beam events Positive electronic tests during first beam run (August 06 : integrated pot) Next CNGS run : Autumn 2007 interaction in magnet (Fe)  More than 300 registred events correlated in time with beam : interactions inside the rock and inside the detector (TT and spectrometers) First events from the CNGS neutrino beam detected in the OPERA experiment R. Acquafredda et al 2006 New J. Phys

12 Muon track inside emulsions First OPERA results with target bricks from cosmic run (May 07) April 17th- May 15th : ~30 bricks extracted 18 scanned 8/18 muons already found in emulsions Cosmic muons in OPERA detector (ray bandle) < 1 event per day inside the acceptance ! ~20 ‘good’ bricks per month first data confirm the good accuracy of the ED predictions Prediction accuracy : Δx = 5.5 mm (along the tray) Δy = 0.4 mm (vertical direction) Δθx = 16.6 mrad Δθy = 24.8 mrad

13 Conclusion OPERA is the first experiment for  appearance in a  beam Hybrid detector with passive lead target and active electronic detectors Electronic parts fully instrumented and tested Bricks yet inserted in the detector - full detector expected for summer 2008 First results -Neutrino events have been observed in emulsions from PEANUT NUMI test-beam -CNGS beam run in August 2006 : electronic detectors gave good results -Cosmic run : brick candidate extraction ; scanning and analysis on the way to validate the full analysis chain Future Next CNGS beam run : Autumn 2007 with ~ bricks and a beam intensity of integrated pot  180 expected events in bricks

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15 6.9m 1.7 m 64 strips/module Target Tracker ● ●Trigger:  > 99% ● Brick finding :   70  80% ● Initiate muon tagging Plastic scintillator strips (AMCRYS-H, 6.7m x 2.6cm x 1cm) readout by Kuraray WLS fibres + Hamamatsu PMT’s (64 channels) LNGS Tracker wall 2 x 256 strips Reconstructed cosmic track

16 Muon spectrometer B= 1.55 T base slabs coil 8.2 m M ~ 950t Drift tubes 12 Fe slabs (5cm thick) RPC’s 2 cm gaps  identification:  > 95% (TT)  p/p < 20%, p < 50 GeV/c misidentified  charge prob.  0.1  0.3% 21 bakelite RPC’s (2.9x1.1m 2 ) / plane Precision tracker: 6 planes of drift tubes diameter 38mm, length 8m 4 staggered layers / plane, each layer consisting of 168 tubes efficiency:  99% space resolution:  300µm Inner Tracker: 11 planes of RPC’s

17 Reconstruction of micro-tracks (45µm) 2D images processing 3D reconstruction of particle tracks speed : 20cm²/hour/emulsion side Résolution (grains) spatial : 0.06 µm Angular : ~ 2 mrad 1 emulsion sheet (2 sides) : 12h scanning - ~5Go 15 scanning laboratories in Europe and Japan 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

18 PEANUT : OPERA test-beam at FERMILAB Detector placed in the front of the MINOS near detector: -4 walls of 3*4 OPERA bricks exposed to NUMI beam (  ) in « low energy » configuration ( =10GeV, E peak =3GeV ) -DONUT SFT (scintillators) between each wall goal : to observe neutrino interactions in OPERA bricks 5  events/brick /day expected bricks exposed ~20days Exposure time: October 18th > Mars 1st 2006 total 160 Bricks made, exposed and developped Brick piling in dark room developper Salerno scanning lab analysis Neutrino reconstruction in emulsions SFT-emulsions alignment ~500µm spatial resolution ~5mrad angular resolution

19   e oscillation search  m 23 2  m 23 2 = 2.5 x eV 2  23 = 45° nominal CNGS beam5 years 90% C.L. limits on sin 2 (2  13 ) and  13 : Combined fit of E e, E vis, (pt) miss sin 2 (2  13 )<0.06  13 < 7.1º 2.5x10 -3 eV 2

20 October 27th 2006 shutdown : leaking Drain Connection in the reflector cooling system Outer conductor (Al) Titanium joints Ceramic insulator (500V) (brazed to the Ti joints) Clamps for vapor tightness Rupture point – leak!! Bellows to give (some) flexibility Reason for rupture : Alignment errors and geometry too rigid Vibration Accident during assembly (?) Improvements of new design drain connection : Absorb better any misalignment errors Water and vapour tightness maintained Rigourous Quality during assembly Reparing on the way for Autumn 2007