Search for appearance via neutrino oscillations in the CNGS beam with the OPERA experiment Amina ZGHICHE For the OPERA Collaboration (LAPP-Annecy IN2P3-CNRS Universit de Savoie ) The present picture Neutrino oscillation experiments Natural neutrino sources: solar neutrinos Homestake, SAGE+GNO, Super-K, SNO, Borexino atmospheric neutrinos Super-Kamiokande Artificial neutrino sources: reactor neutrinos Chooz (1 km), KamLAND (180 km) long-baseline accelerator experiments K2K (250 km), MINOS (735 km) 2/20A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de SavoieBLOIS 2009 Three Flavour Oscillation parameters 3-flavour effects are suppressed because m 2 21 | m 2 31 | and 13 1 dominant oscillations are well described by effective two-flavour oscillations SK (1998): atmospheric neutrino anomaly interpretable as oscillation CHOOZ: no e oscillation SK disappearance oscillation signal confirmed by K2K and MINOS 3/20A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de SavoieBLOIS 2009 The CNGS Beam Line The detector completion The event selection flowchart The scanning factory CC events How many ? When? OPERA: First Direct observation of appearance 4/20A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de SavoieBLOIS 2009 CERN LNGS 730 km From SPS: 400 GeV/c Cycle length: 6 s Extractions: 2 separated by 50 ms Pulse length: 10.5 s Beam intensity: proton/extr. Expected performance: 4.5 pot/year Gran Sasso underground laboratories: Under 1400 m of rock The CNGS Beam: The long baseline experiment in Europe 17 GeV beam from CERN to Gran Sasso Gran Sasso surface laboratories OPERA 2006 Pilot run: after commissioning in Aug, short follow-up in October due to a problem in the cooling of one horn. Moreover, no lead target yet in OPERA 2007: Major problems in the radiation shielding of the ventilation system. Only 810 17 pot. Significant interventions during winter shutdown OPERA fully operational (see below). Performance of the CERN injection complex was poor at the beginning but steadily improving. After the LHC accident, further increase of the integrated intensity for OPERA (duty cycle 37.5% 83%). The 2008 run was the first long physics run for the CNGS June 1 st : 2009 Run Start 5/20A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de SavoieBLOIS 2009 Total: 1.7810 19 pot 18kV cable repair MD PS magnet exchange, septum bakeout MD SPS timing fault: vacuum leak & magnet exchange CNGS maintenance SPS extraction line: Magnet ground fault MD CNGS maintenance Nominal: pot/yr for 5 years Beam to CNGS, LHC, FT, MD Beam to CNGS, LHC, FT Beam to CNGS, MD A closer look to Run 2008: 18 June- 03 Nov A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de Savoie BLOIS 2009 7 Unix time Saturday 30/5/09 Run start 1/6 CNGS access on Wednesday 3/6 (PLC temperature probes) pot 2.68 E 18 pot (0.173 E 18 pot collected during CNGS commissioning) PS vacuum leak 10/6 00:00 11/6 1:07 Pot collected up to Monday 15/6/2009 8:00 (beam stop for MD) A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de SavoieBLOIS 2009 The completion of the OPERA construction (*) OPERA is based on the only proven technology (DONUT) to identify on an event-by-event basis (nucl.emuls.&lead driven by real time detectors). It will be recognized as a major engineering achievement since it brought such technology to a huge size (1.25 kton) 8 (*) R.Acquafredda et al., The Opera experiment in the CERN to GS beam; [OPERA Collaboration], JINST 4 (2009) P04018. OPERA is a hybrid detector built running in parallel with several ancillary facilities which have been fully validated at nominal speed in 2008 Mar 07 Jun bricks have been produced and installed in the detector (1.25 kton mass) 9 OPERA as a real-time detector CNGS-LNGS syncronization: based on GPS. Present precision is 100 ns (can be improved up to 10 ns) DAQ livetime >99%. Collected events correlated with CNGS: on time (mainly in surrounding material) and 1663 in the target Direction and momentum reconstruction for CNGS event Charge and momentum reconstruction for off-time events (cosmic ray analysis) OK [Negligible bkg from cosmics] OK In progress 10 A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de Savoie BLOIS 2009 Event selection flowchart: Brick finding Volume scan for vertex location and event reconstruction try again with the second most probable brick (MC expected 80%) the brick is developed (70% success in event location) the brick is put back in the detector Are the tracks found compatible with the expectations from the real time detectors ? YES(60%)NO Use data from the real-time detectors (scint hits, # p.e., identified tracks in the target and spectrometers) to build a probability map of the bricks where the interaction might have occurred The most probable brick is extracted and the corresponding Changeable Sheet is detatched developped and scanned (sample=700) A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de Savoie BLOIS /18 OPERA as a hybrid detector Prediction of the brick where the interaction occurredAlignment and development of the Changeable Sheets Scanning of the Changable Sheets Extraction of the Bricks at the rate of CNGS eventsIdentification of the primary vertexKinematic reconstruction and decay search (*) Extr. of 1 brick nearly completed. 2 in progress. (**) First results below on a subsample of ~200 events 12 Part. validated (*)Fully validated In progress (**) Fully validated MC independent test of track finding efficiency in CS in a subsample of fully located event ( sb ~ 90%) OK! BrickCSd LNGS (Italy) NAGOYA (Japan) 13 The scanning factory (I):Scanning of the Changeable Sheets The scanning factory (II): Brick development Many operations in series: extraction, X-ray alignment, detatchment of CS, development of CS, exposure of bricks to cosmics rays, development of bricks End of CNGS run Up to 25 bricks per shift (8h). OK! Also brick tracing in a DB, development and logistics have been a big engineering enterprise! 14 data collection from emulsions In progress: vertex efficiency with large statistics Backscattering studies charm topologies search Scanning Factory (III):Vertex finding and decay search Test sample ~200 fully rec. events seems OK, full results need a couple more months. 2 1 CSd CSd general scan: 50 cm 2 around TT prediction angular range 400 mrad alignment by Xray marks (10mm accuracy) Scan back: alignment using cosmic ray tracks (2mm accuracy) stopping point Volume Scan: 1 cm 2, 10 plates track IP Multiplicity 15 A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de SavoieBLOIS 2009 PRELIMINARY Analysis june 18 th 2009 Vertex location summary, 2008 run At least 1 CS track connected in brick: 94% Located events: 73% Passing through (wall misidentification): 5% Interactions in dead material: ~ 2% 16/20 A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de Savoie BLOIS 2009 NCCCTotal Bricks received in the labs Scanning started CS to brick connected Vertices located in the brick Passing through Vertices in the dead material41519 17 pair opening angle 10 mrad E = 157 MeV low p track A beautiful CC ECC level 17 A charm candidate Kink PRELIMINARY e.m. showers vertex signature already visible in the CS The charmed hadron is inside the hadronic jet and back to back with the muon Charm search 8 candidates found for 10 expected in a sample of ~550 CC 18 kink angle = rad Decay length = 3247 m p(daughter) = GeV p t = 796 MeV p t MIN = 606 MeV (90% CL) The charm decay kink Secondary Vertex (1 prong decay) 19 Conclusion CNGS has delivered a significant integrated intensity in 2008 (~2 p.o.t.). It represents the first real physics run for OPERA ("The detection of neutrino interactions in the emulsion/lead target of the OPERA experiment",N. Agafonova et al., published in 2009_JINST_4_P06020). The construction of OPERA is completed; the subdetectors and the ancillary facilities are fully operational. Already after 6 months from the end of CNGS data taking, most of the analysis chain has been validated. This is a crucial milestone for this experiment. We plan to complete the last steps (vertex and kinematic analysis of the full sample) in a few weeks. A lot of physics can be drawn from this sample. Moreover, 0.7 taus are waiting for us 2009 smooth re-start of the RUN after recovering from the earthquake at L'Aquila (april, 6th 2009) 20 A.Zghiche LAPP-Annecy IN2P3-CNRS Universit de Savoie BLOIS 2009