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Status of the OPERANeutrino Oscillation Experiment
6-8 January 2010, Cracow, Poland
Sergey DmitrievskyJoint Institute for Nuclear Research, Dubna
on behalf of the OPERA Collaboration
CRACOW EPIPHANY CONFERENCEOn Physics in Underground Laboratories and Its Connection with LHC
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OutlineOutline
1. About the Experiment2. The OPERA Detector3. Data Analysis4. Present Status of OPERA
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BelgiumIIHE-ULB Brussels
CroatiaIRB Zagreb
FranceLAPP AnnecyIPNL LyonIPHC Strasbourg
GermanyHamburgMünsterRostock
ItalyBariBolognaLNF FrascatiL’Aquila,LNGSNaplesPadovaRomeSalerno
JapanAichiTohoKobeNagoyaUtsunomiya
IsraelTechnion Haifa
KoreaJinju
RussiaINR RAS MoscowNPI RAS MoscowITEP MoscowSINP MSU MoscowJINR Dubna
SwitzerlandBernETH Zurich
TurkeyMETU Ankara
180 physicists, 33 institutions in 12 countries
TunisiaCNSTN Tunis
The OPERA CollaborationThe OPERA Collaboration
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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 µ disappearance signal of Super-K
The challenge of OPERA is to measure the appearance of ν in a pure ν beam
Physics Motivation of the ExperimentPhysics Motivation of the Experiment
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Gran Sasso National LaboratoryGran Sasso National Laboratory
B
C1 cosmic.m-2.h-1
LNGS – the largest underground laboratory in the world
completed in 1987
CERN A
Constructed byprof. A.Zichichi’s proposal
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CERN
LNGS
730 km
CERN
LNGS
730 km
OPERA
Gran Sasso< E > 17 GeV
(CC + NC)/year ~4700
CC/year ~20
( e + e) / 0.87%
/ 2.1%
prompt negligible
L = 732 Km
GPS
CNGS BeamCNGS Beam
The beam is optimized to maximize the number of CC interactions
ντ
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Two conflicting requirements: Large mass low Xsection High spatial resolution
signal selection background rejection
Target: ~1250 tons,22.5E19 pot during 5 years
• >20000 neutrino interactions• ~100 interactions• ~10 identified• <1 background event
-
Decay “kink”
-
~1 mm
oscillation
-
Events Topological SignatureEvents Topological Signature
decay channel
B.R.
(%)
Signalm2 = 2.5E-3 eV2
Background
17.7 2.9 0.17
e 17.8 3.5 0.17
h 49.5 3.1 0.24
3h 15.0 0.9 0.17
Total 10.4 0.75
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OPERA ECC BrickOPERA ECC Brick
125mm
100mm
75.4mm
8.3kg10X0
OPERA emulsion film
Lead plate
57 emulsion films56 Pb plates
sensitivity: 36grains/100micron = 0.06m
intrinsic tracking accuracy:
2 emulsion layers
(44 m thick)poured on a
200 m plastic base
beam
Pb
1 mm
“Emulsion Cloud Chamber”
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20 m
10 m
Muon
Spectrometer
TARGET TRACKERS• Trigger task• Brick identification• 2 x 31 scintillating strip walls read with PMT• 0.8 cm resolution
INNER TRACKERS• 990-ton dipole magnets
(B = 1.55 T) RPC resolution ~1.3 cm
HIGH PRECISION TRACKERSspatial resolution < 0.5 mm
Veto Drifttubes
RPC
53 BRICK WALLS• ~150000 bricks• ~1.25 kton Brick Manipulator
System
Detectorconstruction:Sept. 2003 - Spring 2007
10 m
Target Target
JINST 4 (2009) P04018
RPC and drift tubes for µidentification, charge and momentum measurement
OPERA Hybrid DetectorOPERA Hybrid Detector
SM1 SM2
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Event trigger and reconstruction Brick identification
Selection of a brick most probably containing the neutrino interaction– Reduce scanning load– Minimize the target mass loss
Brick Finding TaskBrick Finding Task
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CS - Interface emulsion films: high signal/noise ratio for event trigger and scanning time reduction
ECC
2.6cm beam
Changeable Sheet (CS)
Scin. strips
Angular accuracy of the electronic predictions
Position accuracy of the electronic predictions
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SM1 SM2
Brick Manipulator System
Extract Brick and CS, scan CS.Confirm the event in the ECC brick.Develop brick and send to scanning labs.
Target area (ECC + CS + TT)
Muon spectrometer (Magnet+RPC+PT)
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Validated bricks are sent to the scanning labs.~10 scanning labs share the scanning.
To Japan
Padova
To Mosccow
GS
Parallel Analysis of ECC BricksParallel Analysis of ECC Bricks
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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
Emulsion Scanning StationsEmulsion Scanning Stations
Both systems demonstrate:• ~0.3 m spatial resolution• ~2 mrad angular resolution• ~95% base track detection
efficiency
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15
ECC
Large area scan~100cm2
Point Scan~100x100m2
Lead
emul
sion
Lead
emul
sion
Lead
emul
sion
Lead
emul
sion
Lead
emul
sion
Lead
emul
sion
Lead
emul
sion
emul
sion
emul
sion
neutrino
CS TT
Decay Search ProcedureDecay Search Procedure
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~2 µm
Volume scanning (~2 cm3) around the stopping point
Track Follow-up and Vertex FindingTrack Follow-up and Vertex Finding
test beam
P M
CS (G
eV)
P beam (GeV)
Evaluate scattering of particles
Track follow-up film by film
• alignment using cosmic ray tracks
• definition of the stopping point
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IP
Z
emulsionlead
Decay Search: Impact Parameter DistributionDecay Search: Impact Parameter Distribution
Impact parameter of tracks at the primary vertex
2.4 µm on averagerelevant for the decay search
DataDataDataData
MCMC
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Located Neutrino InteractionEmulsion 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
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• Neutral charmed particle decay vertex mistaken as primary vertex in events where only a muon and D0 are produced at primary vertex
τ
Good understanding of charm production is mandatory for/before measurements
Charm EventsCharm 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
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Topological identification and kinematical confirmation of a charm event
Primary vertex
Decay vertex
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2000: approval of the CNGS project2003: start of detector construction2004: end of beam civil engineering
2006: commissioning (empty detector’s target) • 7.6E17 pot2007: short pilot run (40% target) • 8.2E17 pot, 38 ν events in the target2008: 1st physics run • 1.78E19 pot, 1663 ν events in the target, 0.7 ντ expected2009: 2nd physics run • 3.52E19 pot, 3693 ν events in the target, ~2 ντ expected in total1 year CNGS nominal:
4.5E19 pot
Progress of the ExperimentProgress of the Experiment
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Unix time
Saturday 30/5/09
pot
PS vacuum leak
10/6 00:00 11/6 1:07
MD
Monday 15/6 8:00
Friday 19/6 8:00
MD + Septum water leak
Tuesday 30/6 8:00
Friday 3/7 7:15
MD
10/8 0:0
13/8 17:24
MD
12/7 1:07
16/7 8:00
MD
31/7
LINAC2 vacuum leak
29/8 20:49
2/9 9:00
MD
26/8
PS magnet
busbar short
3/9 4:23
4/9 22:06
MD 14/9-18/9
MD 22/9-23/9
CNGS ventilation 28/9
PS septum
2/10-11/10
MD 3/11-5/11C
Monday 23/11/09
Foreseen stops
Unforeseen stops
3.522E19 pot
Pot collected during the 2009 CNGS run
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Status of event location in Europe for 2009 run
Time
Nb
of
Even
ts
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• 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• ~20 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
SummarySummary