ICARUS A Second-Generation Proton Decay Experiment and … · 2004. 2. 20. · CERN-SPSC - Sept 3, 2002 3 The ICARUS programme: introduction (I) OICARUS was initially proposed to

CERN-SPSC - Sept 3, 20021

ICARUSA Second-Generation Proton

Decay Experiment and Neutrino Observatory at the

Gran Sasso LaboratoryCERN/SPSC 2002-027

(SPSC-P-323)


The ICARUS Collaboration

S. Amoruso, P. Aprili, F. Arneodo, B. Babussinov, B. Badelek, A. Badertscher, M. Baldo-Ceolin, G. Battistoni, B. Bekman, P. Benetti, A. Borio di Tigliole, M. Bischofberger, R. Brunetti, R. Bruzzese, A. Bueno, E. Calligarich,

D. Cavalli, F. Cavanna, F. Carbonara, P. Cennini, S. Centro, A. Cesana, C. Chen, Y. Chen, D. Cline, P. Crivelli,A. Dabrowska, Z. Dai, M. Daszkiewicz, R. Dolfini, A. Ereditato, M. Felcini, A. Ferrari, F. Ferri, G. Fiorillo, S. Galli,

Y. Ge, D. Gibin, A. Gigli Berzolari, I. Gil-Botella, A. Guglielmi, K. Graczyk, L. Grandi, K. He, J. Holeczek, X. Huang, C. Juszczak, D. Kielczewska, J. Kisiel, L. Knecht, T. Kozlowski, H. Kuna-Ciskal, M. Laffranchi, J. Lagoda, Z. Li,

B. Lisowski, F. Lu, J. Ma, G. Mangano, G. Mannocchi, M. Markiewicz, F. Mauri, C. Matthey, G. Meng, C. Montanari, S. Muraro, G. Natterer, S. Navas-Concha, M. Nicoletto, S. Otwinowski, O. Palamara D. Pascoli, L. Periale,

G. Piano Mortari, A. Piazzoli, P. Picchi, F. Pietropaolo, W. Polchlopek, T. Rancati, A. Rappoldi, G.L. Raselli, J. Rico, E. Rondio, M. Rossella, A. Rubbia, C. Rubbia, P. Sala, D. Scannicchio, E. Segreto, Y. Seo,

F. Sergiampietri, J. Sobczyk, N. Spinelli, J. Stepaniak, M. Stodulski, M. Szarska, M. Szeptycka, M. Terrani, R. Velotta, S. Ventura, C. Vignoli, H. Wang, X. Wang, M. Wojcik, G. Xu, X. Yang, A. Zalewska, J. Zalipska,

C. Zhang, Q. Zhang, S. Zhen, W. Zipper.

University and INFN of: L'Aquila, LNF, LNGS, Milano, Naples, Padova, Pavia, Pisa - ItalyETH Hönggerberg, Zürich - Switzerland IHEP, Academia Sinica, Beijing - ChinaCNR Istitute of cosmogeophysics, Torino - Italy Politecnico di Milano - ItalyUniversity of Silesia, Katowice - Poland University of Mining and Metallurgy, Krakow - Poland

H.Niewodniczanski Inst. of Nucl. Phys., Krakow - Poland Jagellonian University, Krakow - PolandCracow University of Technology, Krakow - Poland A.Soltan Inst. for Nucl. Studies, Warszawa -

Poland Warsaw University, Warszawa - Poland Wroclaw University, Wroclaw - PolandUCLA, Los Angeles - USA University of Granada - Spain


The ICARUS programme: introduction (I)

ICARUS was initially proposed to INFN in 1993ICARUS-II. A Second Generation Proton Decay Experiment And Neutrino Observatory At The Gran Sasso Laboratory Proposal, VOL I (1993) & II (1994), LNGS-94/99.

The proposal was based onThe novel detection technique of the liquid argon TPCIts extrapolation to large (kton) massesTo provide a rich physics programme

Proton decayAtmospheric neutrinosSolar neutrinosSupernovae neutrinos

In addition, the potentialities for LBL neutrino oscillations from CERN were already covered in such proposal.


The ICARUS programme:introduction (II)The ICARUS detector has been approved in 1997 by the Italian INFN and it is currently financed as an integral part of the LNGS programme. In view of the innovative nature of the LAr technology, a graded approach is being followed:1. A full scale 600 ton module, “the first in a series”, has been constructed

in Pavia, in collaboration with industry. 2. The successful operation of the T600 half-module during the Summer

2001 has demonstrated that the technique has matured.3. With a physics program of its own, the installation of the T600 has been

recommended by GSSC. It will be placed in Hall B of LNGS during Summer 2003, and commissioned for physics right after.

4. In order to reach the design mass, the cloning of the T600 for further modules has been recommended by GSSC:

“(…) urges both the collaboration and the laboratory to work closely together on carrying out a complete risk analysis including all the safety relevant data of the final module (resembling the possible base element of T3000)”

5. INFN Comm II has approved the T3000 scientific programme and the design of successive T1200 modules (design is now ongoing in collaboration with industry). The first T1200 module is funded.

6. The upgrade foresees extending the T600 with two new T1200 modules by early 2006. Total active liquid argon mass: 2003: 476 ton; Q4 2004: 1430 ton; Q4 2005: 2380 ton.


Recent presentations at CERN

“A proposal for a CERN-GS long baseline and atmospheric neutrino oscillation experiment”, SPSC, September 1999“A Status Report on the LAr detector construction”, SPSC, September 2000“Liquid Argon Imaging: a Novel Detection Technology”, Carlo Rubbia, CERN Seminar, February 2002

The ICARUS R&D has also been extensively reported in publications (see also http://www.aquila.infn.it/icarus and http://www.cern.ch/icarus and links therein)



Past experience and results - 50 liter prototype

νµ + N Æ m- + X

Active volume : 50 litersReadout planes: 2 (0°,90°)Max drift distance: 45cm

Reconstruction of vertices of ν-interactionsFermi-motionTrack direction by δ-raysdE/dx versus range for K,π,p discriminationMax. electron lifetime > 10 ms

• LAr purification by Ar vapour filtering and re-condensation

• LAr purity monitors• Optimization of front-end electronics for

induction and collection planes• Warm and cold electronics• Readout chain calibration studies• Signal treatment• Collection of scintillation light• 1.4 m drift length (special test)

νµ + n → µ − + p


Past experience and results - 15 ton prototype

Total volume : 10 m3

Readout planes: 2 (–60°,60°)Max drift distance: 35 cm

Final electronicsDAQExternal trigger100 days run in LNGS external hallMax. electron lifetime ≈ 2 ms

• Purification in liquid phase• HV feed-throughs• Cryogenic technology• Signal feed-throughs• Variable geometry drift chamber

wireT15 installation @ LNGS (Hall

di Montaggio)


Experience and results - 300 ton detector

Total volume : 350 m3

Readout planes: 3 (–60°,60°,0°)Max drift distance: 150 cm

Full scale technical run of the T300 detector in Pavia:Cryogenics (decrease the LN2 consumption)Wire chamber mechanicsArgon purificationElectronic noiseHigh voltage for the drift (also at 150 KV)PMTs for scintillation light collection Readout & DAQSlow control

Development of event reconstruction SW with real events and data analysis (ongoing effort)

ImagingEvent reconstruction3 plane readoutCalibrationResolution


≈300‘000 kg LAr= T300

ICARUS T300 cryostat (1 out of 2)


Cryostat (half-module)

20 m

4 m

4 m

View of the inner detector

ICARUS T300 prototype

Readout electronics


Answering the SPSC request: The 18 meter long track…

“The Committee congratulates (…) progress (…) in the construction of the T600 module and awaits recording of long tracks in this module.”, SPSC September 2000


18 m1.5

m1.5

m

Left

Cha

mbe

rRi

ght

Cham

ber

Cathode

Longitudinal muon track crossing cathode plane

Track Length = 18.2 m

3D ViewTop View

dE/dx = 2.1 MeV/cm

dE/dx distribution along the trackdE/dx distribution along the track3-D reconstruction of the long track

3-D reconstruction of the long track



T600 prototype performance

The technical run in Pavia in summer 2001 has allowed not only to ascertain the maturity of large scale liquid Argon imaging TPC, but has also allowed to collect (in addition of the 18 m long track) a large number of C.R. events

About 28000 triggers have been accumulatedThese events provide valuable data to check the performance of a detector of such large scale. We find that:results of the same quantitative quality as those obtained with smaller prototypes (e.g. 3 ton, 50 liter, …) have been achieved with a 300 ton device.

Scaling up is successful.


Readout principle

Drift direction

Edrift

• Continuously sensitive

• Self-triggering

Equiv. input charge due to noise:Equiv. input charge due to noise:Qnoise = 350 + 2.5 × Cinput [pF]( ) electrons

Time


Signal extraction procedure

f(t) = B + A et - T0τ2

1 + et - T0τ1

Collection plane wire analysis: charge = signal area

-20

-10

0

10

20

30

40

50

60

0 500 1000 1500 2000 2500 3000 3500 4000

Time sample / 400 ns

AD

C c

ount

s

0

5

10

15

20

225 250 275 300 325 350 375 400

MeanRMSALLCHAN

1618. 1124. 2987.

P1 37.85 0.9865P2 315.6 0.2797P3 6.813 0.3357P4 2.089 0.7602E-01P5 0.2983 0.9538E-01

Time sample / 400 ns

AD

C c

ount

s

Multimuon event

Run 959 Event 17

(Collection Left wire no. 5228)

τ2τ1

T0

A

B

The same empirical function used to fitmuon hits and test pulse hits

B = baselineA = amplitudeτ1 , τ2 = rise and fall timeT0 = peak position

… find the equivalence between charge and ADC counts = CALIBRATION

FACTOR


Linearity and calibration

Electronics Linearity and Calibration factors (Runs 880 → 905)

0

500

1000

1500

2000

2500

3000

3500

0 10 20 30 40 50

P1 -1.833 0.8268P2 72.60 0.7738E-01

1 mV

2 mV

4 mV

6 mV

8 mV

10 mV

12 mV

15 mV

Test pulse in Analog Board

Calibration factor ≈ 0.0138 fC / ADC count

Charge (fC)

Mea

n H

it In

tegr

al (A

DC

cou

nts)

Electronics Linearity and Calibration factors (Runs 914 → 918)

0

1000

2000

3000

4000

5000

6000

7000

0 20 40 60 80 100 120

P1 0.2274E-01 0.9969E-01P2 71.80 0.3553E-01

Test pulse in Decoupling Board

Calibration factor ≈ 0.0139 fC / ADC count

Charge (fC)

Mea

n H

it In

tegr

al (A

DC

cou

nts)

For each channel and for each value of the injected charge:• calculate the hit integral (= charge)• plot it as a function of the input charge (fC)• fit the distribution to a straight line (1/slope gives the

calibration factor)

Analog Boards: 0.0138 ± .01% fC / ADC count

Decoupling Boards: 0.0139 ± 0.05% fC/ADC count

Good agreement Analog ↔ Decoupling boards

0.0138 ± 3% fC / ADC count(error mainly due to test capacitances nominal accuracy)


3D reconstructionThe 3D reconstruction is based on the fact that the drift time coordinate (y-coordinate) is shared among all three views.The matching between the views is redundantly done at the “hit”-level

p = 2.99 mmθ = 60ºω0 = 528f = 2.5 MHz

Θ


Stopping muon reconstruction exampleµ+[AB] → e+[BC]

Collection view

Induction 2 view

A

A

B

B

C

C

µ+

e+

µ+e+

Te=36.2 MeVRange=15.4 cm

Te=36.2 MeVRange=15.4 cm

Induction 1 view

Run 939 Event 95 Right chamber


0

20

40

60

80

100

1000 1050 1100 1150 1200 1250 1300

P1 190.0P2 1117.P3 6.824P4 3.594P5 0.6043E-02

Signal region / 400 ns

AD

C c

ount

s

0

10

20

30

40

50

1000 1050 1100 1150 1200 1250 1300

P1 42.81P2 1099.P3 7.293P4 2.969P5 85.50P6 1131.P7 6.788P8 2.620P9 0.7629E-01


AD

C c

ount

s

µ

3.2 MeV

Two consecutive

wires

δ-raysT600

1.8 MeV10 MeV


Left chamber (collection view)

Muon bundle event (Run 959, Event 17)

22 used tracksRight chamber (collection view)

10 used tracks


Landau distribution from single event (32 tracks)Right chamberLeft chamber

0

20

40

60

80

100

120

0 2.5 5 7.5 10 12.5 15 17.5 20

MeanRMSALLCHAN

9.385 2.371 1391.

P1 69.46 1.063P2 8.392 0.5917E-02P3 0.4926 0.8838E-02P4 0.7248 0.1424E-01

Charge (fC)

# ev

ents

∆z ≈ 1.1 cm

0

100

200

300

400

500

600

700

800

0 2.5 5 7.5 10 12.5 15 17.5 20

MeanRMSALLCHAN

5.412 2.174 6692.

P1 541.3 2.058P2 4.345 0.7933E-03P3 0.2952 0.1288E-02P4 0.6666 0.1682E-02

Charge (fC)

# ev

ents

∆z ≈ 0.6 cm

All hits from all tracks after lifetime correctionLandau + Gauss fit

∆mp = 4.34 ± 0.15 fC

∆mp = 8.39 ± 0.28 fC

1391 entries6692 entries


Stopping muon automatic reconstruction (I)1.

5 m

0.6 m

drift

wire

1.5

m

0.9 m

drift

wire

Run 966 Event 8Right chamber


Stopping muon automatic 2D reconstruction (II)1.

5 m

0.6 m

drift

wire

0.9 m

1.5

m

drift

wire

Run 966 Event 8Right chamber


Stopping muon automatic 3D reconstruction (III)

025

5075

100

95010001050

180

200

220

240

260

280

300

320

y (cm)z (cm)

x (c

m)

Muon

Comptonelectrons

Electron


Displaced electron from muon decay lifetime

∆t≈8 µs

Run 962, Event 17

Induction 2 view

µ

e (25 MeV)

Collection view

∆t


×

×

×µ

e1 (9 MeV)

e+ e- pair (24 MeV)

(2.5 MeV)

µ

e1

e+e- pair

0

10

20

30

40

50

350 400 450 500 550 600 650

P1 35.87P2 484.8P3 13.33P4 3.822P5 74.10P6 537.6P7 5.249P8 3.430P9 21.41P10 438.9P11 7.449P12 1.385P13 -0.6669


AD

C c

ount

s

Collection view

Induction 2 view

Bremsstrahlung + Pair-production

Run 975, Event 163

Fitted signal shapes on single

wire

Fitted signal shapes on single

wire


In-flight annihilation of positron≈20% of positron from µ decays expected to annihilate before stopping

µ+

e+ (13 MeV)

γ

e+e- pair (20 MeV)

(2.6 MeV)

×

Run 844, Event 24

Collection viewInduction 2 view

Annihilation point


Bremsstrahlung track selection

0�5�

10�15�

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965�970�975�980�985�

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190�

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Rejection of noise and out of time tracks:

• θ < 40º

• d < 60cm


Fully reconstructed stopping muon event

020

4060

9509609709809901000

180

200

220

240

260

280

300

y (cm)

z (cm)

x (c

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θ=158

µ (E=329 MeV, range=1.3m)

θ=103

e (E=30.5 MeV, range=11.5cm)

γ (E=5.7 MeV)

o

o

940

960

980

1000

0 20 40 60y (xm)

z (c

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ϕ=188

ϕ=232o

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µ (E=329 MeV, range=1.3m)

e (E=30.5 MeV, range=11.5cm)

γ (E=5.7 MeV)

Y-Z plane projection(longitudinal cut)


Calorimetric reconstruction Michel electrons

0

5

1010

1515

2020

2525

3030

0 10 10 20 20 30 30 40 40 50 50 60 60 70 70 80 80

EntrieEntries

MeanMean

RMSRMS

160 160

25.07 25.07

11.48 11.48

Energy (MeV)Energy (MeV)

Data Data e

MC MC e

PRELIMINARYPRELIMINARY

T600

Good agreement between data and MC


Reconstruction Bremsstrahlung photons

T600

10-2

10-1

1

10

0 5 10 15 20 25 30 35 40 45 50

Entries

Mean

RMS

60

6.833

6.189

Brems track energy (MeV)

Data

MC

PRELIMINARY

1

10

10 2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Entries

Mean

RMS

123

0.1224

0.1483

Radiation loss rate

Data

MC

PRELIMINARY



Final electron spectrum with Bremsstrahlung photons

0

2.5

5

7.5

10

12.5

15

17.5

20

0 10 20 30 40 50 60 70 80

Entries

Mean

RMS

123

27.90

12.98

Energy (MeV)

Data e+b

MC e+b

PRELIMINARY

T600

σE

= 13 ± 2( )%E(MeV )

- 1.8 ± 0.3( )%


Preliminary resolution:

Low energy electrons


Pi zero candidate (preliminary)

Collection view

•Reconstruction of γ-showers

158 MeV

θ = 141o

Minv = 650 MeV

752 MeV

Run 975, Event 151

θ = 25o

140 MeV Minv =140 MeV


An undeground observatory for rare processes


LNGS Hall B


The Basic Layout of the T1200 unit

Shock Absorbers


ICARUS detector configuration in LNGS Hall B (T3000)

≈ 35 Metres

First Unit T600 + Auxiliary

Equipment

First Unit T600 + Auxiliary

Equipment

T1200 Unit(two T600

superimposed)

T1200 Unit(two T600

superimposed)

T1200 Unit(two T600

superimposed)

T1200 Unit(two T600

superimposed)

≈ 60 Metres


53 c

m

K+

µ+

e+

p → K+ νe

_

K+[AB] → µ+[BC] → e+[CD]

K+

µ+ e+

Run 939 Event 46

p=425 MeV

Proton decay65 cm


Particle identification (I)dE/dx in 3 ton

0

2

4

6

8

10

12

14

0 5 10 15 20 25�

Range (cm)

dE/d

x (M

eV/c

m)

Wires pitch = 5mmNoise = 20 keV

Kaons

Pions

0

20

40

60

80

100

120

-1 -0.5 0 0.5 1 1.5 2 2.5 3

Distance from the fit function (MeV)

77 % of kaons inside,no pions

kaons

kaons decayingin flight

pions

(b)(a)

Energy loss profile along kaon and pion tracks and distribution of the distance from the kaon fit function along pion and kaon tracks.


Particle identification (II)dQ

/dx

(cou

nts/

wire

)

Range from end point (cm)

Pion dE/dx

Proton dE/dx

0 2 4 6 8 100

50

100

150

200

300

250

Particle id. by dE/dx vs rangein the ICARUS 50 liter LAr TPC

dE/dx in 50 liter

K+

µ+

Run 939 Event 46

dE/dx in T600


Proton decay: direct comparison with SuperK

SuperK results compiled by M. Goodman for NNN02, January 2002

Water Cerenkov are notoriously good at back-to-back three-rings events hence in eπ0 and µπ0 channels channels SuperK gains on the mass, even though backgrounds are round the cornerIn the favoured p→νK channel, the efficiency is LAr is ≈10 times better than the channels investigated

ICARUS T3000 fiducial is equivalent to 23.5 kton H2O to be compared toSuperK 22.5 kton


SuperK e+π0 final state candidate1997-09-24 12:02:48 : cut by SuperK because compatible with background

Particle momentum Particle momentum thresholds in Waterthresholds in Water:•Electron 0.6 MeV/c•Muon 120 MeV/c•Pion 159 MeV/c•Kaon 568 MeV/c•Proton 1070 MeV/c


210 cm70

cm

p → e+ π0

2γ

e+γ

γ

Missing momentum 150 MeV/c, Invariant mass 901 MeV

pe=474 MeV pπ0=417 MeV

Proton decay

Not cut by ICARUS because of no background !


Proton decay (II): existing SuperK results

?

>4σ

Note that many are preliminary.Many in the range of a few 1032 yearsBackgrounds are round the corner and not well understood !

p→eK0 with K0 → ππ has excess of 6 vs 1 expectedTaking sum of all other proton channels one gets 1 seen for 5.2 expected !Backgrounds for neutron decays unsatisfactory

Table presented by M. Goodman @ NNN02, January 2002


Proton decay: ICARUS expected sensitivities

Extremely low backgroundsInclusive analyses accessibleRelevant results for few kton × year exposure alreadyExpected range in few 1032 years after 5 kton × year exposures.


Atmospheric neutrinosPresent situation:

SuperK will resume this year with 50% coverageICARUS will look with a completely new technique to such astrophysical source

The atmospheric neutrino analysis in ICARUS will be characterized byAn unbiased, systematic-free observation whereas

SuperK is in practice limited to single-ring CC eventsAll other analyses rely on MC to extract signals (e.g. “NC enriched sample”, τ-appearance neural net based, …)

An excellent energy and angular reconstructionExperimental and theoretical advances in prediction of the atmospheric neutrino rates which will match the improved measurements possible with ICARUS

Expertise within the CollaborationExpect improvements in:

Low energy eventsClean electron sampleAll final states, and with neutrino and antineutrino statistical separationNeutral currents


Atmospheric ratesMass is not the only issue!


Atmospheric νµ interaction, Eν=1.73 GeV240 cm

µ-

p

9m

0 c

50 cm

65 c

m

pe-

Atmospheric νe interaction, Eν=0.730 GeV


Reconstruction of atmospheric neutrinos

Containment≈60% of νµ CC events are fully containedContained tracks will be measured by range and calorimetrically (integration of dE/dx)

≈7%/√E(MeV) for stopping tracks≈12%/√E(MeV) for soft electrons due to Bremsstrahlung≈3% %/√E(GeV) for electromagnetic showers

Range vs dE/dx provides particle identificationMeasurement of escaping tracks (mostly muons) can be performed in different ways

By multiple scatteringExploit the momentum dependence of the scatteringσp/p ≈ 0.10 + 0.048ln(p[GeV]) for 5 meters long tracks

By precise measurement of the energy loss rateExploit the relativistic rise of dE/dx precisely determined by combining successive samplesσp/p ≈ 20-30 %


Muon Muon momentum reconstruction by multiple scatteringmomentum reconstruction by multiple scattering

Analysis on stopping muons in the T600

in T600


Reconstructed L/E distribution

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Oscillation parameters:∆m2

32 = 3.5 x 10-3 eV2

sin2 2Θ23 = 0.9sin2 2Θ13 = 0.1

Electron sample can be used as a reference for no oscillation case

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After 10 years…P(να → νβ ) = sin2 2θ sin2 1.27∆m2 LE

∆(L / E)RMS ≈ 30%


Astrophysical low energy neutrinos: solar and supernovae

Bahcall, http::/www.sns.ias.edu/~jnb

Supernova neutrino energy spectra

0

0.025

0.05

0.075

0.1

0.125

0.15

0.175

0.2

0.225

0 10 20 30 40 50 60Eν (MeV)

Neu

trin

os(

x 10

57)

νe

ν-e

νµ+ντ+ν-

µ+ν-

τ


Low energy reactions in ArgonElastic scattering from neutrinos (ES)

Electron-neutrino absorption (CC)

Elastic scattering from antineutrinos (ES)

Electron-antineutrino absorption (CC)

φ(νe)+0.15 φ(νµ + ντ) νx +e− →νx +e−

νe +40Ar→40K* + e−φ(νe) Q=5.885 MeV

ν e + 40Ar→40Cl* + e+

φ(νe)+0.34 φ(νµ + ντ)

φ(νe)Q≈8 MeV

ν x + e− → ν x + e−


ICARUS and the CNGS beam (I)

ICARUS as a LBL neutrino oscillations experiment between CERN and LNGS was already discussed in the 1993 proposal

The simultaneous study of accelerator and non-accelerator sources is possible due to the nature of the detection technique

Continuously sensitive and isotropic

The CNGS events will be separated from other events by timing requirement on the CERN SPS spill

The ICARUS physics program will be enriched by CNGS oscillation searches.

The ICARUS collaboration has already contributed to the design and optimization of the CNGS beam.


ICARUS and the CNGS beam (II)

The real-time detection, the excellent granularity and energy resolution of the liquid argon TPC allows to collect and identify interactions from CNGS neutrinos

νµ CC: study online the beam profile, steering and normalization;

νe CC: search for νµ→νe oscillations with the best sensitivity until the JHF-SK program turns on;

ντ CC: search for νµ→ντ oscillations with a sensitivity at least similar to that of the OPERA experiment;

NC events: search for νµ→νs oscillations or exotic models.


ICARUS-CNGS experiment

7505 x 10-3

2803 x 10-3

1252 x 10-3

311 x 10-3

ντ CC, ∆m2 (eV2)243ν NC

10600ν NC17νe CC

262νe CC652νµ CC

32600νµ CCExpected RatesProcess

Detector configurationT3000Active LAr: 2.35 ktons

5 years of CNGS runningShared mode 4.5 x 1019 p.o.t./year

280 ντ CC expected for ∆m2

23=3 x 10-3 eV2 and maximal mixing


CNGS Beam Profile Measurement

1 year = 4.5x1019 pots(CNGS official “shared” mode)

2400 events/year

νµ energy beam profile for a T600 + T1200 detector configuration

0

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35 40 45 50

νµ CC simulated Evis

νµ CC measured Evis

Evis (GeV)

Eve

nts

/2G

eV/y

ear

Average resolution on total visible energy: ≈10%


A. External muon spectrometerAlready in 1999, the Collaboration had put forward the possibility to complement the liquid Argon imaging by an external device capable of magnetic analysis of escapingmuons.Physics motivation:

Measure the muon charge via magnetic analysisOnline beam energy spectrum monitoringKinematical properties of closed νµ CC events

Direct measurement of background for τ searchesImprove momentum resolution of muons by combining multiple scattering and magnetic bending analysis

Magnet design:Strategy: simple design, compatible with the large transverse dimensions of the T1200 module

Detection technique:Drift tubes + fast trigger devices

B. Front muon “veto”•Muon detection walls:

Beam monitoring & tagging of rock interactions


Artist view spectrometer

Muon spectrometer

ν


Basic Magnet Parameters


CNGS νµ interaction, Eν=26 GeV420 cm

µ–

Vertex : 3 π0 , 1p, 3γ, 1µ

13m

0 c

CNGS νµ interaction, Eν=21.3 GeV300 cm

Vertex: 3π,5p,9n,3γ,1µ80 c

m


CNGS ντ interaction, Eν=18.7 GeV280 cm

τ- → e- + ν e + ντ

_

e-, 9.5 GeV, pT=0.47 GeV/c

290 cm

105

cm

_

e-, 15 GeV, pT=1.16 GeV/c

Vertex: 1π0,2p,3n,2 γ,1e-

CNGS νe interaction, Eν=16.6 GeV

120

cm


Event kinematics reconstruction

0�

20�

40�

60�

80�

100�

120�

0� 5� 10� 15� 20� 25� 30�

Mean�RMS�

16.24� 6.553�

E�visible� (GeV)�

Eve

nts�

Argon�

No quenching�

0�

20�

40�

60�

80�

100�

120�

0� 5� 10� 15� 20� 25� 30�

Mean�RMS�

16.68� 6.529�

E�visible� (GeV)�

Eve

nts�

TMG-doped Argon�

No quenching�

Evisible

1�

10�

10�2�

0� 0.2� 0.4� 0.6� 0.8� 1� 1.2� 1.4� 1.6� 1.8� 2�

Mean�RMS�

0.4184� 0.2638�

Missing P�T� (GeV)�

Eve

nts�

Argon�No quenching�

1�

10�

10�2�

0� 0.2� 0.4� 0.6� 0.8� 1� 1.2� 1.4� 1.6� 1.8� 2�

Mean�RMS�

0.3947� 0.2590�

Missing P�T� (GeV)�

Eve

nts�

TMG-doped Argon�No quenching�

Missing PT

<Missing PT> ≈ 410 MeV


Direct detection of flavor oscillation

Expected νe and ντ contamination (in absence of oscillations) is of the order of 10–2 and 10–7 relative to the main νµ component

eννµννh−nh0νh−h+h−nh0ν

18%18%50%14%

τ→Charged current (CC)

ντ+Ar→τ+jet;νµ→ ντ

νµ→ νe νe+Ar→e+jetCharged current (CC)


τ→e search: 3D likelihood

5 T600 modules, 5 years CNGS (4.5 x 10�19� p.o.t./year)�

0�

5�

10�

15�

20�

25�

30�

35�

40�

-2� 0� 2� 4� 6� 8� 10�ln�λ

Eve

nts/

12 k

ton

x ye

ar�

νe� CC + �ντ CC�

νe� CC�

ντ CC, �τ→ e�

Overflow�

lnλ

Vertex cuts applied

A simple analysis approach: a likelihood method based on 3 variables

3 variablesEvisible, PT

miss, ρl≡PTlep/(PT

lep+

PThad+PT

miss)Exploit correlation between them

LS ([Evisible, PTmiss, ρl]) (signal)

LB ([Evisible, PTmiss, ρl]) (νe CC

background)Discrimination given by

lnλ ≡L([Evisible, PTmiss, ρl]) =

Ls / LB

More sophisticated approaches (e.g. neural net,…) under study.


τ→e search: 3D likelihood summary

5 year “shared”CNGS running T3000 configuration

Maximum sensitivity


νµ→ ντ appearance search summary

T3000 detector (2.35 kton active, 1.5 kton fiducial)Integrated pots = 2.25 x1020

Super-Kamiokande: 1.6 < ∆m2 < 4.0 at 90% C.L.

Several decay channels are exploited (golden channel = electron)(Low) backgrounds measured in situ (control samples)High sensitivity to signal, and oscillation parameters determination


Oscillation parameters determinationCNGS + ATMOSPHERIC combined data

0.001

0.002

0.003

0.004

0.005

0.006

0 0.2 0.4 0.6 0.8 1

sin2 Θ23

∆ m

2 32 (

eV2 )

(90% C.L.)90

% C

.L. S

uper

K a

llow

ed

ICARUS1 T600 + 2 T1200 modules

Five years exposure

5 years exposure combining beam and atmospheric neutrino events(within the same detector!)

δ ∆m 2( )Dm2 ª 10%


Search for subleading νµ→νe (I)

U =1 0 00 c23 s23

0 - s23 c23

Ê

Ë

Á Á Á

ˆ

¯

˜ ˜ ˜

c13 0 s13e- id

0 1 0- s13e

- id 0 c13

Ê

Ë

Á Á Á

ˆ

¯

˜ ˜ ˜

c12 s12 0- s12 c12 00 0 1

Ê

Ë

Á Á Á

ˆ

¯

˜ ˜ ˜

The emerging scenario:| ∆m2

21 | =(4÷12)×10–5 eV2

tan2θ12 = 0.32÷0.51 ⇒ 30°<θ12<36°|∆m2

32|=(1.6÷3.9)×10–3 eV2

sin22θ23 > 0.92⇒ 37°<θ23<45°

The confirmation that νµ→ντ oscillations will be an important milestoneThe measurement of a non-vanishing θ13 would

Be an important discovery, proving that the mixing matrix is 3x3 and opening the door to search for CP-violation searches in the leptonic sector !(note that CP-violation effects will only be visible for relatively large θ13)

atm ??? solar


Search for subleading νµ→νe (II)Search for excess of electrons, on top of electronic decays of tauTakes advantage of unique e/π0 separation in ICARUSAssume 5 years @ 4.5x1019 pots, 2.35 kton fiducialLimited by statistics, needs more intensity at low energy to fully exploit capabilities of ICARUS

∆m232=3x10–3 eV2; sin22θ23 = 1


For ∆m2= 2.5×10

–3eV2:


ConclusionThe ICARUS agenda foresees:

Initial operation with the T600 at LNGS, with data taking of astrophysical events in 2003; the progressive realisation of two additional T1200 modules —starting from the T600 as basic cloning unit — to be operational around 2006.

In this mass configuration, because of the unique potentials offered by the LAr technology, ICARUS will be able to perform a vast physics program in the domain of

Proton decayAtmospheric neutrinosSolar and supernovae neutrinos

• Within this context, it would be very valuable to take advantage of the realization of the CNGS beam in order to:• Provide real-time study of the beam properties• Search for νµ→νe and νµ → ντ flavor appearance

Because of the continuous nature of the detector, both original ICARUS programmes and its extension to CNGS could be performed simultaneously (and at a small added cost).

Documents

ICARUS A Second-Generation Proton Decay Experiment and … · 2004. 2. 20. · CERN-SPSC - Sept 3, 2002 3 The ICARUS programme: introduction (I) OICARUS was initially proposed to