Status of the OPERA Neutrino Oscillation Experiment

1. Status of the OPERANeutrino Oscillation Experiment Sergey Dmitrievsky Joint Institute for Nuclear Research, Dubna on behalf of the OPERA Collaboration CRACOW EPIPHANY CONFERENCE On Physics in Underground Laboratories and Its Connection with LHC 5-8 January 2010, Cracow, Poland

2. Outline 1. About the Experiment 2. The OPERA Detector 3. Data Analysis 4. Present Status of OPERA

3. Belgium IIHE-ULB Brussels Russia INR RAS Moscow NPI RAS Moscow ITEP Moscow SINP MSU Moscow JINR Dubna Italy Bari Bologna LNF Frascati L’Aquila, LNGS Naples Padova Rome Salerno Croatia IRB Zagreb Switzerland Bern ETH Zurich France LAPP Annecy IPNL Lyon IPHC Strasbourg Tunisia CNSTN Tunis Japan Aichi Toho Kobe Nagoya Utsunomiya Turkey METU Ankara Germany Hamburg Münster Rostock Israel Technion Haifa Korea Jinju The OPERA Collaboration 180 physicists, 33 institutions in 12 countries

4. Physics Motivation of the Experiment Super-K (1998): atmospheric neutrino anomaly interpretable as µ→ oscillation CHOOZ (reactor): µ→e oscillation could not explain the anomaly K2K and MINOS (accelerator) confirmed the µdisappearance signal of Super-K The challenge of OPERA is to measure the appearance of ν in a pure ν beam

5. Gran Sasso National Laboratory LNGS – the largest underground laboratory in the worldcompleted in 1987 1 cosmic.m-2.h-1 C B CERN A Constructed by prof. A.Zichichi’s proposal

6. CERN 730 km LNGS CNGS Beam CERN  Gran Sasso 730 km LNGS OPERA GPS L = 732 Km ντ The beam is optimized to maximize the number of CC interactions

7. - nm n n n Decay “kink” - nm oscillation t- nt ~1 mm Events Topological Signature • Target: ~1250 tons, • 22.5E19 pot during5 years • >20000 neutrino interactions • ~100nt interactions • ~10nt identified • <1 background event • Two conflicting requirements: • Large masslow Xsection • High spatial resolution signal selection background rejection

8. OPERA emulsion film Lead plate OPERA ECC Brick 75.4mm 125mm 57 emulsion films56 Pb plates 8.3kg 10X0  beam 1 mm 100mm  “Emulsion Cloud Chamber”  intrinsic tracking accuracy: sensitivity:36grains/100micron = 0.06m Pb 2 emulsion layers (44 m thick) poured on a 200 m plastic base

9. JINST 4 (2009) P04018 OPERA Hybrid Detector Detector construction: Sept. 2003 - Spring 2007 Target RPC Target Drift tubes Veto Muon Spectrometer SM1 SM2 10 m 10 m 20 m • 53 BRICK WALLS • ~150000 bricks • ~1.25 kton Brick Manipulator System HIGH PRECISION TRACKERS spatial resolution < 0.5 mm • TARGET TRACKERS • Trigger task • Brick identification • 2 x 31 scintillating strip walls read with PMT • 0.8 cm resolution RPC and drift tubes for µ identification, charge and momentum measurement • INNER TRACKERS • 990-ton dipole magnets • (B = 1.55 T) • RPC resolution ~1.3 cm

10. Brick Finding Task Event trigger and reconstruction Brick identification Selection of a brick most probably containing the neutrino interaction • Reduce scanning load • Minimize the target mass loss

11. CS - Interface emulsion films: high signal/noise ratio for event trigger and scanning time reduction Scin. strips Position accuracy of the electronic predictions ECC 2.6cm beam Changeable Sheet (CS) Angular accuracy of the electronic predictions

12. SM1 SM2 Extract Brick and CS, scan CS. Confirm the event in the ECC brick. Develop brick and send to scanning labs. Brick Manipulator System Target area (ECC + CS + TT) Muon spectrometer (Magnet+RPC+PT)

13. To Mosccow Padova To Japan GS Parallel Analysis of ECC Bricks Validated bricks are sent to the scanning labs. ~10 scanning labs share the scanning.

14. Emulsion Scanning Stations EU: ESS (European Scanning System) Japan: SUTS (Super Ultra Track Selector) • Scanning speed/system: 75cm2/h • High speed CCD camera (3 kHz),Piezo-controlled objective lens • FPGA Hard-coded algorithms • Scanning speed/system: 20cm2/h • Customized commercial opticsand mechanics • Asynchronous DAQ software Both systems demonstrate: • ~0.3 m spatial resolution • ~2 mrad angular resolution • ~95% base track detection efficiency

15. Decay Search Procedure TT ECC CS Large area scan~100cm2 Point Scan ~100x100mm2 neutrino emulsion emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion Lead emulsion 15

16. P MCS (GeV) p test beam P beam (GeV) Track Follow-up and Vertex Finding Volume scanning (~2 cm3) around the stopping point Evaluate scattering of particles Track follow-up film by film • alignment using cosmic ray tracks • definition of the stopping point  ~2 µm

17. Decay Search: Impact Parameter Distribution MC lead emulsion IP DZ Data Data Impact parameter of tracks at the primary vertex 2.4 µm on average relevant for the decay search

18. Located Neutrino Interaction Emulsion gives 3D vector data, giving a micrometric precision of the vertexing accuracy. (The frames correspond to scanning area. Yellow short lines  measured tracks. The other colored lines  interpolation or extrapolation. The colors indicate the Z-depth in the module.) 1 cm

19.   τ Charm Events Charm topology is analogous to  (similar lifetime and mass): – Reference sample for the tau decay finding efficiency – It is also important to identify the muon in charm events in order to suppress this background • Neutral charmed particle decay vertex mistaken as primary vertex in events where only a muon and D0 are produced at primary vertex Good understanding of charm production is mandatory for/before  measurements

20. Topological identification and kinematical confirmation of a charm event Primary vertex Decay vertex

21. Progress of the Experiment 2000: approval of the CNGS project2003: start of detector construction 2004: end of beam civil engineering 2006: commissioning (empty detector’s target) • 7.6E17 pot 2007: short pilot run (40% target) • 8.2E17 pot, 38 ν events in the target 2008: 1st physics run • 1.78E19 pot, 1663 ν events in the target, 0.7 ντ expected 2009: 2nd physics run • 3.52E19 pot, 3693 ν events in the target, ~2 ντexpected in total 1 year CNGS nominal: 4.5E19 pot

22. Pot collected during the 2009 CNGS run pot Monday 23/11/09 3.522E19 pot PS septum 2/10-11/10 MD 3/11-5/11C CNGS ventilation 28/9 Foreseen stops Unforeseen stops MD 22/9-23/9 PS magnet busbar short 3/9 4:23 4/9 22:06 MD 14/9-18/9 MD 26/8 LINAC2 vacuum leak 29/8 20:49 2/9 9:00 MD 31/7 MD 10/8 0:0 13/8 17:24 MD 12/7 1:07 16/7 8:00 MD + Septum water leak Tuesday 30/6 8:00 Friday 3/7 7:15 MD Monday 15/6 8:00 Friday 19/6 8:00 Saturday 30/5/09 PS vacuum leak 10/6 00:00 11/6 1:07 Unix time

23. Status of event location in Europe for 2009 run Nb of Events Time

24. Summary • OPERA successfully operates on the CNGS neutrino beam and have just finished to take data for the 2nd physics year • CNGS performances improved: 2008+2009 were~ 1 nominal year, 2010 expected as a nominal year • ~ 1100 interactions have been located till this moment • 19 charm candidates found: systematic decay search started with an uniform selection on all the data sample • Analysis of 2009 progressing while completing the queue of 2008 run • First (s) expected soon in the analysis of 2008/09 runs

25. Backup Slides

26. Brick Assembly Machine Xray machine Brick Manipulator System Emulsion Development Facility

27. CNGS Beam Performances 10.5 ms 10.5 ms 50 ms 2E13 pot First Extraction 2E13 pot GPS synchronization with 100 ns accuracy Second Extraction SPS super-cycle with 4 CNGS cycles with LHC 49.2 s, without 39.6 s Cosmic-ray background CNGS New J. Phys. 8 (2006) 303

28. The L’Aquila Earthquake A strong earthquake (MI=6.2) hit L’Aquila on April 6th 2009. The epicenter was 15 km away from the Gran Sasso laboratory. 306 killed, 1600 injured, many houses collapsed, 15000 buildings were damaged. OPERA found basically intact, geometric measurements showed no significant alignment changes. Gran Sasso activities, stopped for ~1.5 months. Big OPERA effort to let CNGS start 2009 run with only 2 weeks delay !