Neutrino Oscillation Appearance with OPERA

Neutrino Oscillation Appearance with OPERA

Amina ZGHICHE

Oscillation Project with Emulsion tRacking Apparatus

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Neutrino : a SM particle as any other

• It fits in the SM picture

arXiv:hep-ex/0509008Phys.Rept.427:257-454,2006

Nlight_n= 2.9840± 0.0082

YES

2/8/2013 QM UoL Amina ZGHICHE-LAPP

http://arxiv.org/abs/hep-ex/0509008

http://arxiv.org/abs/hep-ex/0509008

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• Has a mass and Very low one (< 1 eV/c2 )• Hint for physics beyond the SM• May be its own anti-particle• Only a weakly interacting particle• Produced as a coherent mix of three mass

eigenstates in the weak interaction processes• Oscillates• Many parameters already precisely measured and

some still not known

Neutrino : a SM particle as any other?Not quite


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Oscillation and mass:

• MNSPMaki-Nakagawa-Sakata-Pontecorvo neutrino mixing Matrix: 4 parameters to be determined +2 (∆m2)

• Oscillation Probability:

n

3

1jjU jn

Uj : mixing matrix element


SNO

ne g ne,m,t sun

2000

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PANORAMA of the Oscillation measurements byDISAPPEARANCE (last 15 years)

atmospheric showers (L ~20 et 12 000 km)

Superkamiokande

nm g nm

1998

Neutrino beam (L ~730 km)

nm g nm Minos

2005 Reactor (L ~180 km)2008


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The appearance case with OPERA

≈/4 </15 ≈/6

Requirements:1- High neutrino energy2- High beam intensity3- Long Baseline4- Detection of short lived t‘s (10-12 s )5- Massive Underground detector2/8/2013 QM UoL

Amina ZGHICHE-LAPP

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CNGS Description

SPS protons: 400 GeV/c• Every: 6 s, two pulses of 10.5 ms separated by 50 ms• Proton pulses extracted by kicker magnet• Beam intensity: 2.0 x 1013

proton/extraction• ~ pure muon neutrino beam (<E> = 17 GeV)

REQUIREMENTS 1 AND 2


CNGS Experiments at LNGS

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730

REQUIREMENT 3


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REQUIREMENT 4

• Target basic unit: ECC brick = nuclear emulsion films interleaved bylead plates + 2 interface emulsion films (CS) Massive target withmicrometric space resolution• Electronic detectors to provide “time resolution” to the emulsion filmsand preselect the interaction region2/8/2013 QM UoL

Amina ZGHICHE-LAPP

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OPERA Detector

+REQUIREMENT 5


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OPERA: POTs and Neutrino interactions

Year Proton On Target (POT)

Number ofNeutrino

interactions

Integrated POT/ Proposal

Value

2008 1.78x1019 1698 7.9%

2009 3.52x1019 3557 23.6%

2010 4.04x1019 3912 41.5%

2011 4.84x1019 4210 63.0%

2012 ~4.0x1019 ~3892 ~80%

ALL ~18x1019 ~17270 ~80%Expected interactions for 22.5 1019 pot~ 23600 nm CC+NC~ 170 ne + anti-ne CC~ 115 nt CC (∆m2 =2.5 x 10-3 eV2)

<E(nm)> 17 GeV

L 730 km

L/E 43 km/GeV

(ne + ne )/ nm CC 0.87%

nm/nm CC 2.1%

nt prompt negligible


Neutrinos seen by the OPERA Electronic detectorThe first data taking

“INTERNAL or contained”EVENTS

“EXTERNAL” CC-EVENTS(neutrino interactions in the rock)

12/40

With µ• nµCC• nτ CC, t m (17.4%)

Without µ or NC-like• nNC• nτCC, t e (17.8%)• nτCC, t h, 3h (49.2%,15.2%)• neCC

-like


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OPERA Sensitivity to Neutrino Oscillations

t decaychannel

B.R.(%) Signal Back-ground

t m 17.41 1.79 0.09t e 17.83 2.89 0.22t h 49.16 2.25 0.24t 3h 15.20 0.71 0.18

ALL BR*eff~8% 7.63 0.73


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The background

t Decay channel t m t e t h t 3h All

Charm 0.02 0.22 0.14 0.18 0.55m Scattering 0.07 0. 0. 0. 0.07h interact. 0. 0. 0.11 0. 0.11

ALL 0.09 0.22 0.24 0.18 0.73

5 years of nominal beam (4.5 1019pot/year)All channels: BR*global efficiency ~8%Possible additional kinematical variable analysis (t h)Need solid understanding of hadronic system by comparing to real data (nmCC)

Primary lepton not identified.Good (95%) m identification mandatory

nmm- nm nm

h h

nm,em-,e-

D+ m+ e+ h +

Charm production in CC (all channels) Coulomb large angle scattering of m in Pb (t m)

Hadron interactions in Pb (t h)


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OPERA DETECTOR FEATURES


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The OPERA FIRST Data Taking with Electronic Detectors: ONLINE

n beam

vetoRPC+HPT+Magnet muon spectrometermuon Id, sign and momentum measurement Brick wall and Target Tracker

15K bricks=1.25Kton31 walls per Super Module

Each Brick wall is followed by a Target Tracker planeFor the interaction preselect ion (trigger) and the event localization (brick finding)


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Brick finding

BMS (LAPP-Annecy): • Twin Brick Manipulating System one on each side of the detector.• They run over z,x axis , 18mx10m with a precision of 1-2mmAnd push 26 bricksx8Kg through ~3m• Filled the target and now used to extract the candidate brick

n beam


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The OPERA SECOND Data Taking with SCANNING


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Event Location and vertex reconstruction

Scan Back

Volume Scan

Low Energy tracks

High Energy tracks


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Impact parameter separation power into a decay search process

IP distribution for ντ events(MC)


Momentum Measurement N Agafonova et al 2012 New J. Phys. 14 013026

inthelead/emulsionfilmsandwichandcomparisonwithelectronicdetectormeasurements

MomentummeasurementbyMulipleCoulombScarering

2/8/2013 QM UoL Amina ZGHICHE-LAPP 21/40

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Calibration with nµCC charm eventsSimilar lifetime and decay topology

49 events detected,51. 0± 7.5 expected


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OPERA nm → nt


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First nt candidate event 2008-2009 decay search, released in 2010 (Phys. Lett. B (2010) 138)

Background sources rate

Prompt nt ~10-7/CC

Decay of charmed particles produced in νe interactions ~10-6/CC Double charm production ~10-6/CC

Decay of charmed particles produced in νμ interactions ~10-5/CC

Hadronic reinteractions ~10-5/CC

Variable Value Selection Criteria

Kink(mrad) 41 ±2 >20 Decay length (mm)

1335 ±35 Within 2 lead plates

P daughter (GeV/c)

12 +6 -3

>2

Pt (MeV/c) 470 +230 -120

>300 (g attached)

Missing Pt (MeV/c)

570 +320 -170

<1000

φ (deg) 173 ±2 >90

2010


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Second nt candidate event

Track Momentum(1

interval(GeV/c)

Particle Id

Method/Comment

Primary

2.8(2.1-3.5) hadron Not a muon (stops after 2 bricks), momentum range

OK

d1 6.6(5.2-8.6) hadron Momentum range Ok

d2 1.3(1.1-1.5) hadron idem

d3 2.0(1.4-2.9) hadron) Interaction in the brick at 1.3 cm downstream

2012


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t decaychannel

Signal Back-ground

Charm m scattering h interactions

t m 0.49 0.02 0.01 0.02 0.00

t e 0.68 0.05 0.05 0.00 0.00

t h 0.56 0.06 0.03 0.00 0.03

t 3h 0.18 0.05 0.05 0.00 0.00

ALL 1.91 0.18 0.14 0.02 0.03

Background expectation for the analyzed data (preliminary)

years Status of the analysis

#of events for decay search

Expected nt events (preliminary)

Observed nt Candidate events

Expected background for nt events(preliminary)

2008-2009 completed 2783 1

2010-2011 In progress 1343 1

2012 started

ALL 4126 1.91 2. 0.18

Summary of the data processing

Main background is charm events associated with muon Id failure0.05 BG event expected for the second candidate


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ntgt-+ hadrons et t- g o-

OPERA with CNGS beamnm g nt

730 km2010

T2K with JPARC beam nm g ne

2011

295 km

A 2nd t event observed in 2012

PANORAMA of the Oscillation measurements by APPEARANCE (LAST 3 YEARS) (LBL)

10 candidates back exp. 2.37250km


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Lead to the major breakthrough: 13 measurementT2K : nm g ne

T2K

sin2213 = 0.094 (±10%)

10 candidates back exp. 2.37

LBL appearance of ne

3 experiments: • Double Chooz (France)• Daya Bay (China)• Reno (Korea)

ne g ne Reactors with disappearance of ne

13 large => good for mass hierarchy determination and CP violation searches

2012


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OPERA nm → ne

5.3x1019 pot - 2008-2009 data


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OPERA as an electromagnetic (em) calorimeter 56mm of Pb=10X0 Three steps with a

NN algorithm:- Shower Reconstruction- Identification (separation from pions)- Energy estimation

Shower extension(# films)

ID e

ffici

ency

/5fil

ms

Standard volume

em Shower energy(GeV)

Ener

gy R

esol

ution

PreliminaryMC

PreliminaryMC


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Multi Variable analysis of the nm → ne oscillation channel (1-MC-preliminary)

nm → ne CNGS ne

t → enm NC

nm → ne CNGS ne

t → enm NC

nm → ne CNGS ne

t → enm NC

nm → ne CNGS ne

t → enm NC

PreliminaryMC


Multi Variable analysis of the nm → ne oscillation channel (2-MC-preliminary)

Without MVA: Signal/BG =0.058 With MVA: Signal/BG=0.22 (~4 times improvement)BG suppression needs to be improved2/8/2013 QM UoL

Amina ZGHICHE-LAPP 32/40

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nm → ne search through e.m. showers in the data

Event sample: 505NC-- like events ‐ in 2008 and 2009 For each located event (all tracks found)– Extrapolate each track up to the CS – Search the shower pattern (3 or more track element )on CS– scan back additional volume from the CS hint and perform the e.m. shower reconstruction if found.– 86 events with showers selected– 19 ne events confirmed


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DATA – MC comparison (preliminary)

Data- BG MC-SIGNAL MC

Visible Energy Electron Energy

Missing PT

angle




MVA analysis rate

MC signal region 7.9±2.7

MC BG region 18.8 ± 4.8

Data signal region 6±2

DATA BG region 13±4

Compatible , not significant for oscillation


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OPERA Oscillation Results at Neutrino2012: 2008-2009 data

Observed νe events : 19

Expected νe events:Oscillated νe events :1.5Beam νe BG events :19.2

After low energy event selection (Eν < 20GeV):

Observed νe events: 4

Expected νe events:Oscillated νe events :1.1Beam νe BG events : 3.7

5.3x1019 pot S and BG Compatible , not significant for oscillation


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Any other non standard oscillation

Window left by the full OPERA statistic for sterile?

ICARUS:arXiv:1209.0122v3

Standard three flavour mixing


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Neutrino velocity

CNGS • Proton pulses individually measured (1 ns sampling) • Time stamped and logged in the CERN DB

Synchroni-zation • 2 TWIN high accuracy timing system • Common View Mode

OPERA • Time distributions of the ON TIME events


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2012 measurement with CNGS bunched beam


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Results for neutrino velocityJHEP(2013)153

δtν = (0.7 ± 0.4(stat) ± 1.6(syst.-uncorr.) ± 2.5(syst.-corr)) ns


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Conclusion• OPERA experiment: aimed the direct detection of νμ → ντ oscillations in APPEARANCE MODE, successfully taking

data since 2008,

• Total integrated luminosity: ~18.0x1019 pot ~= 80% of the nominal value (22.5 x 1019)

• 2 νμ → ντ candidate events:

τ→1 prong: τ → ρ(π-π0)ντ

τ → 3 h ντ 1.9 signal and 0.18 background expected

• Preliminary result on the νμ → νe oscillation analysis 19 events observed, 4 with energy < 20 GeV (expected osc. Signal 1.1, BG 3.9) constraints in the high Δm2 region but no final answer foreseen New improved result under final discussion within the collaboration

• About 56% of the data has still to go through the second data taking (scanning…) and analysis

• Neutrino velocity measurement: 2012 bunched beam result: δtν = (0.7 ± 0.4(stat) ± 1.6(syst.-uncorr.) ± 2.5(syst.-corr)) ns 2/8/2013 QM UoL Amina ZGHICHE-LAPP

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THANK YOU FOR THE ATTENTION


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OPERA sensitivity


Full mixing and Δm2

23~2.4x10 3‐ eV2

The green hashed band indicates the OPERAallowed region (90%CL) for theabove parameter value and for 22.5x1019 pot

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6 parameters

m212

|m223 |

sin² 12

sin² 23

sin² 13

d

7.54 10-5 eV²

2.43 10-3 eV²

0.307

0.386

0.024 21%

Precision 2

5%

7%

11%

12%

Valeur ?

Ref: G.L. Fogli et al. arXiv:1205.5254v3

Where we stand in 2012

Signe ?

Échelle de masse ? 2/8/2013 QM UoL

Amina ZGHICHE-LAPP

Neutrino Oscillation Appearance with OPERA

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