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

OutlineOutline

1. About the Experiment2. The OPERA Detector3. Data Analysis4. Present Status of OPERA

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

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

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

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

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

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”

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

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

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

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)

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

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

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

~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

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

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

• 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

Topological identification and kinematical confirmation of a charm event

Primary vertex

Decay vertex

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

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

Status of event location in Europe for 2009 run

Time

Nb

of

Even

ts

• 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