1. /57 Time and Matter, Venice, 04 March 2013 Measurement of the neutrino velocity with the OPERA detector in the CNGS beam Gabriele Sirri Istituto Nazionale di Fisica Nucleare BOLOGNA, ITALY on behalf of the OPERA COLLABORATION

2. /57 OPERA Experiment and CNGS Neutrino Beam Neutrino TOF measurements Geodesy Data analysis – Statistical analysis (2009-2011 data) – 2011 bunched-beam analysis – 2012 bunched-beam analysis Conclusions Contents TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA 2

3. /57 OPERA Experiment CNGS Neutrino Beam TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA3

4. /57 OPERA Collaboration LAPP Annecy IPHC Strasbourg INR Moscow NPI Moscow ITEP Moscow SINP NSU Moscow IRB ZagrebBari Bologna LNF Frascati L’Aquila LNGS Napoli Padova Roma Salerno LHEP BernIHE BrusselsHamburg JINR Dubna Aichi Toho Kobe Nagoya Utsunomiya Technion Haifa METU Ankara Jinjiu International collaboration of ∼ 150 physicists from 28 institutions and 11 countries TAM, Venice 04/03/20134G.Sirri - INFN BOLOGNA http://operaweb.lngs.infn.it/

5. /57 Status of the OPERA experiment TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA5 OPERA: Oscillation Project with Emulsion tRacking Apparatus

6. /57 CNGS CERN Neutrino to Gran Sasso beam TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA6 730 Km CERN LNGS In addition: the experiment is well suited to determine the neutrino velocity with high accuracy throuhg the measurements of the Time Of Flight and the distance between the source of CNGS neutrino beam at CERN and the OPERA detector at LNGS

7. /57 TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA 7 CNGS target magnetic horns decay tunnel hadron absorber muon detector pit 1 muon detector pit 2

8. /57 p + C  (interactions)   , K   (decay in flight)      vacuum 800m100m1000m67m26m Scheme for production of neutrinos (graphite) Two extractions separated by 50 ms, each pulse length: 10.5  s Proton intensity: 2 x10 13 protons on target (p.o.t)/extraction Expected performance: 4.5x10 19 p.o.t./year ~ pure muon neutrino beam ( = 17 GeV) travelling through the Earth’s crust → LNGS Two extractions separated by 50 ms, each pulse length: 10.5  s Proton intensity: 2 x10 13 protons on target (p.o.t)/extraction Expected performance: 4.5x10 19 p.o.t./year ~ pure muon neutrino beam ( = 17 GeV) travelling through the Earth’s crust → LNGS SPS LNGS TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA8

9. /57 3.5 0 TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA 730 km 9

10. /57 Beam parameters 17 GeV p.o.t./year Beam Contamination (interaction rates in OPERA) 0.89%, 0.06% 2.1 % negligible TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA10 CNGS Beam Performance [New Journal of Physics 14(2012)033017]

11. /57 The LNGS underground physics laboratory OPERA CNGS 1400 m 1400 m rock coverage Cosmic µ reduction = 10 -6 (1 µ/m 2 /h) Underground area: 18 000 m 2 External facilities Easy access 800 scientists from 25 countries Research lines Neutrino physics (mass, oscillations, stellar physics) Dark matter Nuclear reactions of astrophysics interest Gravitational waves Geophysics Biology TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA11

12. /57 wall Pb/emulsion SM1SM2 brick wall scintillator strips ν brick (56 Pb/Em.) 8 cm (10X0) 10 X Target Tracker 0 + brick walls (2x31) muon spectrometer 150000 bricks (1.25 kt) (RPC + drift tubes) 8.3kg The OPERA detector TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA12

13. /57 Target Tracker plastic scintillator strips (26.4 mm), σ~8 mm The spectrometers Dipole magnet + Drift tubes RPC (inner tracker) (precision tracker) y Inner tracker coil x (RPC in magnet, σ ~ 13 mm) 12 Fe slabs trigger to PT in total 8.2 m Fe RPC (5 cm) slabs 62 walls (496 modules) 7.5x7.5 m 2 Hamamatsu multianode PMTs (64 channels) Precision Tracker B= 1.55 T base Tube: vertical, ∅ =38 mm, length=8m σ<0.5 mm The Electronic Detectors TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA13

14. /57 «internal» and «external» events TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA14

15. /57 just few slides about neutrino oscillations… TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA15

16. /57 Status of the OPERA experiment Event-by-event direct observation of the τ lepton decay Topology Decay mode B.R. o Micrometric resolution achieved to detect the τ decay kink o Target segmented in small units called «bricks». Brick: 57 layers of nuclear emulsion interleaved with 56 layers of lead1 mm thick. o Initial total target mass ~ 1.25 kt (about 150000 bricks) 10X 0 Emulsion Cloud Chamber TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA16

17. /57 The automatic emulsion scanning Developed grains frame 2-3 µm 15-16 frames/45 microns 1. S-UTS automatic microscopes generation (Japan) 2. European Scanning System. TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA17

18. /57 Status of the OPERA experiment CNGS data taking Bunched beam run periods 2011 22/10 to 6/11 2012 10/05 to 24/05 Event location in emulsion bricks located neutrino interactions 4898 Fully analyzed events4190 2 2.1 BG expected0.2 TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA18 Data Analysis Progress RunProton on Target (p.o.t.) In-target events 20081.8 · 10 19 1698 20093.5 · 10 19 3557 20104.0 · 10 19 3912 20114.8 · 10 19 4210 20123.9 · 10 19 3493 Preliminary In target ev. located extracted scanned Preliminary

19. /57 Phys. Lett. B 691(2010)138 TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA19

20. /57 2° tau candidate NEUTRINO 2012 TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA20

21. /57 Neutrino TOF measurements TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA21

22. /57 FNAL experiment (Phys. Rev. Lett. 43 (1979) 1361) high energy (E > 30 GeV) short baseline experiment. Tested deviations down to |v-c|/c ≤ 4×10 -5 (comparison of muon-neutrino and muon velocities) at 95% C.L. SN1987A (see e.g. Phys. Lett. B 201 (1988) 353) electron (anti) neutrinos, 10 MeV range, 168’000 light years baseline. |v-c|/c ≤ 2×10 -9 at 95% C.L. Performed with observation of neutrino and light arrival time. MINOS (Phys. Rev. D 76 072005 2007) muon neutrinos, 730 km baseline, E ν peaking at ~3 GeV with a tail extending above 100 GeV. (v-c)/c = (5.1 ± 2.9) ×10 -5 at 68% C.L. (significance 1.8  ). Past experimental results TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA22

23. /57 tagging of neutrino production time tagging of neutrino interaction time Precise Time link ~ 2 nsec by GPS Common View Mode Operation + All Possible corrections PolaRx2e + Cs atomic Clock Precise Distance Measurement by GPS + Optical Geodesy measurement BCT OPERA 731278.0 ± 0.2 m GPS Satellite Observed Proton Time Profile = Neutrino Production Time Profile Predicted Neutrino Event Time Profile C CERNLNGS PolaRx2e + Cs atomic Clock 18/26 Nakamura M. (Nagoya Univ.) BCT TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA23 Principle of the neutrino velocity measurement long baseline needed for high accuracy Observed Neutrino Event time Profile

24. /57 already existing system (not enough accurate) new system Time-transfer equipment CERN-LNGS Synchronization already existing system (not enough accurate) TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA24 PolaRx2e, calibrated by METAS (Swiss metrology institute)

25. /57 Standard GPS operation: resolves x, y, z, t with ≥ 4 satellite observations Common-view mode (same satellite for two sites, for each comparison): x, y, z known from former dedicated measurements determine time differences of local clocks (both sites) w.r.t. the satellite, by offline data exchange 730 km << 20000 km (satellite altitude)  similar paths in ionosphere (and make use of more than one frequency !) GPS Common View Mode TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA25

26. /57 Result: TOF time-link correction (event by event) TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA26

27. /57 Independent twin-system calibration by the Physikalisch-Technische Bundesanstalt High accuracy/stability portable time-transfer setup @ CERN and LNGS GTR50 GPS receiver, thermalised, external Cs frequency source, embedded Time Interval Counter Correction to the time-link: tCERN - tLNGS= (2.3 ± 0.9) ns Blue: Code based common-view (P3 ionosphre free linear combination), fixed positions, TR position estimated by PPP Red: Precise Point Positioning (PPP) Relative calibration of CERN-to-LNGS GPS time link TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA27 [http://operaweb.lngs.infn.it/Opera/publicnotes/note134.pdf]

28. /57 30-90 cm WLS FPGA TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA28 LNGS Timing FPGA10 MHz O/E ESAT GPS2 OPERA Master Clock GPS Antenna T 10 Ts ROC PMT TRIGGER DAQ RESET every 600 PPmS MC PPmS T MC N*10 nsM*0.6 s 20 MHz HERTZ 100 MHz DAQ Time Stamp 121 … 122… 123… ESAT PPmS 8 km External Lab Underground OPERA Event Time Stamping Triggers from Target Tracker : time-stamped by an FPGA (100MHz) DAQ cycle : 0.6 s ; Reset and Clock provided by OPERA Master Clock (hall C) FPGA increments two counters: M: coarse counter incremented by DAQ RESET. N : fine counter which increments every 10 ns When a trigger is issued  the FPGA assigns to it the reading of the two counters. DAQ Time-Stamps delayed by the time to transfer the GPS information to the FPGA (red path). Master Clock oscillator: 10 MHz VECTRON OC-050 (stability 10 -12 /s) ± 3.8 ns Scint. Strip T EVENT CTRI PolaRx2e GPS Antenna PPS 121 … 122… 123… CTRI Log

29. /57 Patch Panel 8 km ESAT GPS2 LASER TX ESAT PPmS Patch Panel Splitter HERTZ Fiber 23 LNGS External Lab LNGS Underground OPERA Master Clock 5 m Fiber MC PPmS 5.9 ns TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA29 Time delay from the external Lab to the OPERA Master Clock To FEBs GPS Antenna LVD BOREXINO TX tBtB tAtA ICARUS Time delay t A between 2 reference points: HERTZreference of the GPS2 ESAT UTC time. MC PPmS generated by the OPERA Master Clock, synchronous with the ESAT PPmS The “two-way” technique measure : t A – t B and t A + t B TX RX Scope RX Scope t A – t B t A + t B

30. /57 OPERA data: narrow peaks of the order of the spill width (10.5 µs) Negligible cosmic-ray background: O(10 -4 ) Offline selection procedure kept unchanged since first events in 2006 cosmics D. Autiero - CERN - 23 September 2011 Tagging Neutrino INTERACTION Time @LNGS Typical neutrino event time distributions w.r.t kicker magnet trigger pulse TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA30

31. /57 BCTTargetDecay Tunnel SPS CERN Timing Kicker signal 743.40 m protons π,K ν ts1 CTRI BCT TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA31 Polarx2e Wave Form Digitizer (WFD) XLi CTRI Prevessin Centr. Cont. Room HCA442 General Machine Timing (GMT) High Precision GPS time CTRI in HCA442 tags the reference and the kicker signal and produces a replica of kicker to trigger the WFD Typical waveform (2011) Shape reflects the PS extraction CTRI in Prevessin compares GPS Clock Reference Signal

32. /57 CNGS SPS 2010 calibration with Cs clock Proton timing by Beam Current Transformer Fast BCT 400344 (~ 400 MHz) Tagging Neutrino Production Time = Proton Timing Proton pulse digitization: Acquires DP110 1GS/s waveform digitizer (WFD) WFD triggered by a replica of the kicker signal Waveforms UTC-stamped and stored in CNGS database for offline analysis TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA32

33. /57 Dedicated beam experiment: BCT plus two pick-ups (~1 ns) using the LHC beam (12 bunches, 50 ns spacing) WFD ZOOM result: signal comparison after Δt BCT compensation Amplitude [a.u.] LHC beam time [ns] BCT Calibration BPK1BPK2 BCT WFD SPS CNGS LHC TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA33

34. /57 24.5 BCT OPERA TargetDecay Tunnel SPS LNGS CERN Time Corrections (ns) 41068.6 4262.9 59.6 10085.0 30 580 2.3 Controller Board FPGA TT strip CTRI Kicker signal GPS Receivers BASELINE = 731278.0 ± 0.2 m p π,K ν * C ts1 ts2 other time corrections OPERA M.C. BCT time TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA34 8.3 km fiber CTRI WFD

35. /57 2.0 0.2 2.0 1.0 5.0 3.7 1.0 3.0 2.3 1.7 BCT OPERA TargetDecay Tunnel SPS LNGS CERN Systematic Uncertainty (ns) Controller Board FPGA TT strip CTRI Kicker signal WFD GPS Receivers p π,K ν CTRI OPERA M.C. BCT time Baseline: 0.67 (20 cm) Meson decay point: 0.2 (exponential, 1 side) Interaction point of external events: 2.0 (flat, 1 side) PMT 0.67 8.3 km fiber The overall systematic uncertainty was computed numerically by taking into account the individual contribution and their corresponding probability distribution (gaussian if not written). Overall systematic uncertainty ( -8.0, + 8.3 ) ns TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA35

36. /57 Summary of time corrections (2011) Item Time Correction (ns) Method 1CERN UTC distribution (GMT) 10085 ± 2 Portable Cs Two-ways 2WFD trigger 30 ± 1Scope 3BTC delay 580 ± 5 Portable Cs Dedicated beam experiment 1CERN-LNGS intercalibration 2.3 ± 1.7 METAS PolaRx calibration PTB direct measurement 1LNGS UTC distribution (fibers)41068.6 ±3.7 Two-ways (from new cross checks during 2011 winter shutdown) 2 OPERA master clock distribution 4262.9 ± 1 Two-ways Portable Cs 3 FPGA latency, quantization curve 24.5 ± 1Scope vs DAQ delay scan (0.5 ns steps) 4 Target Tracker delay (Photocathode to FPGA) 50.2 ± 2.3UV picosecond laser Target Tracker response (Scintillator-Photocathode, trigger time-walk, quantisation) 9.4 ± 3 UV laser, time walk and photon arrival time parametrizations, full detector simulation TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA36

37. /57 Cross-Checks during 2011 winter shutdown TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA37

38. /57 + ~74 ns LNGS Dedicated campaign Dec11-Feb12 OPERA M.C. Controller Board FPGA Two identified issues: Faulty connection of the optical fiber to the Master Clock artificially increasing the neutrino anticipation by ~74 ns. Internal Master Clock frequency off by Δf/f = 1.24x10-7 (124 ns/s) artificially decreasing the neutrino anticipation by ~15 ns (DAQ time bin 10 ns → 9.99999877 ns). Time when "anomalous" conditions occurred during data taking and stability of these conditions subjected to "a special investigation" Test of the delay of 8.3 km long optical fiber and of the DAQ internal delays 8.3 km fiber - ~15 ns Frequency distribution 4 TT strip OPERA ν TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA38 ESAT 2000 CTRI

39. /57 Coincidences using horizontal cosmic muons (Joint OPERA-LVD analysis) the fiber problem started in 2008 and lasted until end of 2011 when it has been well connected to the OPERA Master Clock (considered data period: 2009-2011). New systematic uncertainties : ± 3.7 ns. the oscillator is running at a frequency higher than the nominal since 2008. (0.113 ±0.020) ppm Time drift confirmation Time diff. in DAQ cycle (ns) How stable were the «anomalous» conditions ? "anomalous" period 74 ns OPERA-LVD time delay ~ 160 m «Teramo» µ DAQ cycle (0.6 s) [Eur. Phys. J. Plus (2012) 127: 71] TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA39 is flat ± 3.7 ns

40. /57 Details and updated results in : TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA40 2012 February 23, Press Release The OPERA collaboration has identified two issues … 2012 March 12, Report from the OPERA Collaboration to the scientific committees http://operaweb.lngs.infn.it/Opera/ptb/p ubref/pubref/OPERAReport0312toSC.pdf 2012 March 28, Mini-Workshop - "LNGS results on the neutrino velocity topic" http://agenda.infn.it/materialDisplay.py? materialId=slides&confId=4896

41. /57 Geodesy TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA41

42. /57 GPS Dedicated measurements at LNGS: July-Sept. 2010 (Rome Sapienza Geodesy group) 2 new GPS benchmarks on each side of the 10 km highway tunnel GPS measurements ported underground to OPERA Geodesy at LNGS TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA42

43. /57 Resulting distance (BCT – OPERA reference frame) (731278.0 ± 0.2) m CERN – LNGS measurements (different periods) combined in the ETRF2000 European Global system, accounting for earth dynamics (collaboration with CERN survey group) Cross-check: simultaneous CERN-LNGS measurement of GPS benchmarks, June 2011 LNGS benchmarks In ETRF2000 Combination with CERN Geodesy [http://operaweb.lngs.infn.it/Opera/publicnotes/note132.pdf] TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA43

44. /57 Data analysis Statistical analysis (2009-2011 data) TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA44

45. /57 δt= TOF c - TOF ν Positive (negative) δt  neutrinos arrive earlier (later) than light statistical error evaluated from log likelihood curves Maximised versus δt: For each neutrino event in OPERA  proton waveform of the corresponding extraction Sum up and normalize:  PDF W(t)  separate likelihood for each extraction Analysis Method TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA45 ~10 20 pot 7235 internal events 7988 external events

46. /57 no seasonal effect no day/night effect no energy dependence no beam intensity effect no difference between internal and external events. extraction 1extraction 2 New results Total systematic uncertainties computed numerically by taking into account the individual contributions and their corresponding p.d.f. [JHEP10(2012)093] TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA46

47. /57 Data analysis 2011 bunched-beam analysis TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA47

48. /57 2009-2011October 22 to November 6 (2011) TOFν for each detected neutrino 4x10 16 pot 6 internal events 14 external events events evenly distributed in the four bunches of the extraction mode not compatible with OPERA oscillation program. statistical method for TOFν extraction ~10 20 pot 7235 internal events 7988 external events Test with short-bunch wide-spacing proton beam TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA48

49. /57 In agreement with the previous value (6.5±7.4 ns) Excludes possible biases affecting the statistical analysis based on the proton waveforms Indicates the absence of significant biases due to: cumulative response of beam line to long proton pulses pulse duration effects in the BCT response. 20 events δt=1.9±3.7 ns (same syst. errors) [JHEP10(2012)093] Test with short-bunch wide-spacing proton beam Results with the RPC data 16 events Results with the Target Tracker data TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA49

50. /57 Data analysis 2012 bunched-beam analysis TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA50

51. /57 10 to 24 May 2012 Δt=100 ns σ~1.8 ns 1 extraction per CNGS cycle 4 batches per extraction 16 bunches per batch p.o.t.: ~2 x 1017 (2 weeks) TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA51 New measurements with a short-bunch narrow- spacing proton beam (2012)

52. /57 Improvements in the Timing System TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA52

53. /57 New Calibration Delays TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA53 Item Time Correction (ns) Method 1CERN UTC distribution (GMT)10077.8 ± 1 Portable Cs Two-ways 2WFD trigger 26.6 ± 1Scope 3BTC delay 583.7 ± 1 Portable Cs Dedicated beam experiment 1CERN-LNGS intercalibration 2.3 ± 1.7 METAS PolaRx calibration PTB direct measurement 1LNGS UTC distribution (fibers)41067.0 ±1 Two-ways 2 OPERA master clock distribution 7046 ± 1 Two-ways 3 FPGA latency, quantization curve 24.5 ± 1Scope vs DAQ delay scan (0.5 ns steps) 4 Target Tracker delay (Photocathode to FPGA) 50.2 ± 2.3UV picosecond laser Target Tracker response (Scintillator-Photocathode, trigger time-walk, quantisation) 9.4 ± 3 UV laser, time walk and photon arrival time parametrizations, full detector simulation

54. /57 Four Different (correlated) analysis TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA54 using TT (earliest hit) using RPC (all muon hits) RPC using Trigger Boards using TT and all muon hits 1-3 Standard DAQ 4 Timing Board System

55. /57 Final OPERA Results TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA55

56. /57 Other Experiments TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA56 from: P. Adamson, Neutrino 2012, Kyoto

57. /57 Conclusions TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA57

58. /57 Thank you TAM, Venice 04/03/2013G.Sirri - INFN BOLOGNA58