ICARUS A Second-Generation Proton Decay Experiment and Neutrino Observatory at the Gran Sasso Laboratory CERN/SPSC 2002-027 (SPSC-P-323) CERN-SPSC - Sept 3, 2002
1
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 - Italy ETH Hönggerberg, Zürich - Switzerland IHEP, Academia Sinica, Beijing - China CNR Istitute of cosmogeophysics, Torino - Italy Politecnico di Milano - Italy University of Silesia, Katowice - Poland University of Mining and Metallurgy, Krakow - Poland H.Niewodniczanski Inst. of Nucl. Phys., Krakow - Poland Jagellonian University, Krakow - Poland Cracow University of Technology, Krakow - Poland A.Soltan Inst. for Nucl. Studies, Warszawa Poland Warsaw University, Warszawa - Poland Wroclaw University, Wroclaw - Poland UCLA, Los Angeles - USA University of Granada - Spain
CERN-SPSC - Sept 3, 2002
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The ICARUS programme: introduction (I) O
ICARUS was initially proposed to INFN in 1993 ´ ICARUS-II. A Second Generation Proton Decay Experiment And Neutrino Observatory At The Gran Sasso Laboratory Proposal, VOL I (1993) & II (1994), LNGS-94/99.
O
The proposal was based on ´ The novel detection technique of the liquid argon TPC ´ Its extrapolation to large (kton) masses ´ To provide a rich physics programme
Proton decay
Atmospheric neutrinos
Solar neutrinos
Supernovae neutrinos ´ In addition, the potentialities for LBL neutrino oscillations from CERN were already covered in such proposal.
CERN-SPSC - Sept 3, 2002
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The ICARUS programme:introduction (II) O O
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.
CERN-SPSC - Sept 3, 2002
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Recent presentations at CERN O
“A proposal for a CERN-GS long baseline and atmospheric neutrino oscillation experiment”, SPSC, September 1999
O
“A Status Report on the LAr detector construction”, SPSC, September 2000
O
“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) CERN-SPSC - Sept 3, 2002
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CERN-SPSC - Sept 3, 2002
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Past experience and results - 50 liter prototype O O O
Active volume : 50 liters Readout planes: 2 (0°,90°) Max drift distance: 45cm
9Reconstruction of vertices of ν-interactions 9Fermi-motion 9Track direction by δ-rays 9dE/dx versus range for K,π,p discrimination 9Max. electron lifetime > 10 ms • • • • • • • •
LAr purification by Ar vapour filtering and recondensation 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)
CERN-SPSC - Sept 3, 2002
νµ + N Æ m- + X
νµ + n → µ − + p
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Past experience and results - 15 ton prototype O O O
Total volume : 10 m3 Readout planes: 2 (–60°,60°) Max drift distance: 35 cm
9Final electronics 9DAQ 9External trigger 9100 days run in LNGS external hall 9Max. electron lifetime ≈ 2 ms • • • • •
Purification in liquid phase HV feed-throughs Cryogenic technology Signal feed-throughs Variable geometry drift chamber wire
CERN-SPSC - Sept 3, 2002
T15 installation @ LNGS (Hall di Montaggio) 8
Experience and results - 300 ton detector O O O O
O
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 mechanics ´ Argon purification ´ Electronic noise ´ High voltage for the drift (also at 150 KV) ´ PMTs for scintillation light collection ´ Readout & DAQ ´ Slow control Development of event reconstruction SW with real events and data analysis (ongoing effort) ´ Imaging ´ Event reconstruction ´ 3 plane readout ´ Calibration ´ Resolution
CERN-SPSC - Sept 3, 2002
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ICARUS T300 cryostat (1 out of 2)
≈300 ‘000 kg LA = T30 r 0
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Cryostat (half-module)
ICARUS T300 prototype View of the inner detector
4m 4m
20 m
Readout electronics
CERN-SPSC - Sept 3, 2002
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Answering the SPSC request: The 18 meter long track… O
“The Committee congratulates (…) progress (…) in the construction of the T600 module and awaits recording of long tracks in this module.”, SPSC September 2000
CERN-SPSC - Sept 3, 2002
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1.5 m
Left Chamber
Cathode
Right Chamber
1.5 m
18 m
Longitudinal muon track crossing cathode plane
Track Length = 18.2 m
Top View 3-D 3-Dreconstruction reconstructionof ofthe thelong long track track CERN-SPSC - Sept 3, 2002
dE/dx = 2.1 MeV/cm
3D View
dE/dx dE/dxdistribution distributionalong alongthe thetrack track
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CERN-SPSC - Sept 3, 2002
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T600 prototype performance O
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 accumulated
O
These 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.
CERN-SPSC - Sept 3, 2002
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Readout principle
Time • Continuously sensitive Edrift
• Self-triggering
Drift direction
Equiv. Equiv.input inputcharge chargedue dueto tonoise: noise:
Qnoise = (350 + 2.5 × Cinput [pF]) electrons
CERN-SPSC - Sept 3, 2002
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Signal extraction procedure ADC counts
Collection plane wire analysis: charge = signal area 60 50 40 30 20 10 0
The same empirical function used to fit muon hits and test pulse hits
t - T0 τ2
e 1 + e
B = baseline A = amplitude τ1 , τ2 = rise and fall time T0 = peak position
-20
ADC counts
f(t) = B + A
-10
t - T0 τ1
0
500
1000
1500
2000
2500
τ1
τ2
Multimuon event
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Run 959 Event 17 (Collection Left wire no. 5228)
15
A
10
3500
4000
Mean RMS ALLCHAN P1 P2 P3 P4 P5
1618. 1124. 2987. 37.85 315.6 6.813 2.089 0.2983
350
375
0.9865 0.2797 0.3357 0.7602E-01 0.9538E-01
5
B
0 225
250
275
300
325
T0
… find the equivalence between charge and ADC counts = CERN-SPSC - Sept 3, 2002
3000
Time sample / 400 ns
400
Time sample / 400 ns
CALIBRATION FACTOR
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Linearity and calibration Analog Boards: 0.0138 ± .01% fC / ADC count P1 P2
-1.833 72.60
0.8268 0.7738E-01
15 mV
3000 12 mV
Decoupling Boards: 0.0139 ± 0.05% fC/ADC count
2500
Electronics Linearity and Calibration factors (Runs 914 → 918)
10 mV
2000 8 mV
6 mV
1500
4 mV
1000
2 mV
Test pulse in Analog Board
Mean Hit Integral (ADC counts)
Mean Hit Integral (ADC counts)
Electronics Linearity and Calibration factors (Runs 880 → 905) 3500
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)
7000
P1 P2
0.2274E-01 71.80
0.9969E-01 0.3553E-01
6000
5000
4000
Calibration factor ≈ 0.0138 fC / ADC count
500 1 mV
3000 0
0
10
20
30
40
50
Charge (fC) 2000
Good agreement Analog ↔ Decoupling boards
Test pulse in Decoupling Board
1000
0.0138 ± 3% fC / ADC count (error mainly due to test capacitances nominal accuracy) CERN-SPSC - Sept 3, 2002
Calibration factor ≈ 0.0139 fC / ADC count 0
0
20
40
60
80
100
120
Charge (fC)
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3D reconstruction O O
The 3D reconstruction is based on the fact that the drift time coordinate (ycoordinate) is shared among all three views. The matching between the views is redundantly done at the “hit”-level
Θ
p
= 2.99 mm
θ
= 60º
ω0 = 528 f
CERN-SPSC - Sept 3, 2002
= 2.5 MHz
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Stopping muon reconstruction example µ +[AB] → e + [BC]
Run 939 Event 95 Right chamber Induction 1 view A
µ+
B
e+
Induction 2 view
C A
µ+
B
e+ Collection view CERN-SPSC - Sept 3, 2002
C
TTe=36.2 MeV e=36.2 MeV Range=15.4 Range=15.4cm cm
20
δ-rays µ
T600
1.8 MeV 10 MeV
50
P1 P2 P3 P4 P5 P6 P7 P8 P9
40
30
42.81 1099. 7.293 2.969 85.50 1131. 6.788 2.620 0.7629E-01
ADC counts
ADC counts
3.2 MeV 100
P1 P2 P3 P4 P5
80
190.0 1117. 6.824 3.594 0.6043E-02
60
20
Two consecutive wires
10
40
20 0
1000
1050
CERN-SPSC - Sept 3, 2002
1100
1150
1200
1250
1300
Signal region / 400 ns
0 1000
1050
1100
1150
1200
1250
21
1300
Signal region / 400 ns
Muon bundle event (Run 959, Event 17) Left chamber
(collection view)
22 used tracks Right chamber (collection view)
10 used tracks CERN-SPSC - Sept 3, 2002
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Landau distribution from single event (32 tracks) Right chamber
Mean RMS ALLCHAN P1 P2 P3 P4
800
700
5.412 2.174 6692. 541.3 4.345 0.2952 0.6666
# events
# events
Left chamber 2.058 0.7933E-03 0.1288E-02 0.1682E-02
Mean RMS ALLCHAN P1 P2 P3 P4
120
9.385 2.371 1391. 69.46 8.392 0.4926 0.7248
1.063 0.5917E-02 0.8838E-02 0.1424E-01
100
600
∆z ≈ 1.1 cm
∆z ≈ 0.6 cm
500
80
400
60
300
40 200
20 100
0
0 0
2.5
5
7.5
10
12.5
15
17.5
20
0
2.5
5
7.5
10
12.5
17.5
20
Charge (fC)
Charge (fC)
6692 entries
15
All hits from all tracks after lifetime correction
1391 entries
Landau + Gauss fit ∆mp = 4.34 ± 0.15 fC ∆mp = 8.39 ± 0.28 fC CERN-SPSC - Sept 3, 2002
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drift
drift
1.5 m
1.5 m
Stopping muon automatic reconstruction (I)
wire
wire 0.6 m
CERN-SPSC - Sept 3, 2002
Run 966 Event 8 Right chamber 0.9 m
24
drift
drift
1.5 m
1.5 m
Stopping muon automatic 2D reconstruction (II)
wire
wire 0.6 m
CERN-SPSC - Sept 3, 2002
Run 966 Event 8 Right chamber 0.9 m
25
x (cm)
Stopping muon automatic 3D reconstruction (III) 320
300
Muon
280
Compton electrons
260
240
220
200
180
y
Electron
100 75 (cm) 50 25 0
CERN-SPSC - Sept 3, 2002
1050
1000
950
z (cm)
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Displaced electron from muon decay lifetime
∆t≈8 µs Run 962, Event 17
µ
∆t e (25 MeV)
Collection view
CERN-SPSC - Sept 3, 2002
Induction 2 view
27
Bremsstrahlung + Pair-production e+ e- pair (24 MeV)
ADC counts
Run 975, Event 163 50 P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13
40
30
35.87 484.8 13.33 3.822 74.10 537.6 5.249 3.430 21.41 438.9 7.449 1.385 -0.6669
(2.5 MeV)
×
µ
e1 (9 MeV)
×
µ
×
Collection view
e1
20
e+e- pair 10
0
350
400
450
500
550
600
650
Signal region / 400 ns
CERN-SPSC - Sept 3, 2002
Fitted Fittedsignal signal shapes on shapes onsingle single wire wire
Induction 2 view
28
In-flight annihilation of positron ≈20% of positron from µ decays expected to annihilate before stopping Run 844, Event 24
(2.6 MeV) e+e- pair (20 MeV)
γ ×
e+ (13 MeV) µ+
Collection view
Induction 2 view
Annihilation point CERN-SPSC - Sept 3, 2002
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x (cm)
Bremsstrahlung track selection
200
Rejection of noise and out of time tracks:
198 196 194
• θ < 40º
192 190
θ
188
• d < 60cm
186 184
d
182 180
20 15
y (cm)
10 5 0 985
CERN-SPSC - Sept 3, 2002
980
975
970
965
z (cm)
30
x (cm)
Fully reconstructed stopping muon event
Y-Z plane projection (longitudinal cut)
θ=158o
z (cm)
300
280
1000
ϕ=188o
µ (E=329 MeV, range=1.3m)
260
ϕ=232o 240 980
µ (E=329 MeV, range=1.3m) e (E=30.5 MeV, range=11.5cm)
220
γ (E=5.7 MeV) 200
960
θ=103o
180
e (E=30.5 MeV, range=11.5cm) 60
γ (E=5.7 MeV)
40
y (cm)
940 0
20 0 1000
CERN-SPSC - Sept 3, 2002
990
980
970
960
950
20
40
60
y (xm)
z (cm)
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Calorimetric reconstruction Michel electrons Entrie Entries Mean RMS
30
T600
160 25.07 11.48
PRELIMINARY
25
Good agreement between data and MC
Data e
20
MC e
15
10
5
0
0
1 10 0
2 20 0
3 30 0
4 40 0
5 50 0
6 60 0
7 70 0
8 80
Energy (MeV) CERN-SPSC - Sept 3, 2002
32
Reconstruction Bremsstrahlung photons
T600
60 6.833 6.189
Entries Mean RMS
10
PRELIMINARY
10
123 0.1224 0.1483
Entries Mean RMS
2
PRELIMINARY
Data
Data
MC
1
MC
10
-1
10 1
0
0.1
0.2
0.3
0.4
0.5
-2
10
0
0.6
0.7
0.8
0.9
1
Radiation loss rate
5
10
15
20
25
30
35
40
45
50
Brems track energy (MeV)
Good agreement between data and MC CERN-SPSC - Sept 3, 2002
33
Final electron spectrum with Bremsstrahlung photons T600
20
123 27.90 12.98
Entries Mean RMS
Good agreement between data and MC
PRELIMINARY
17.5
Data e+b
15
MC e+b
Preliminary resolution:
12.5
σ
10
E
=
(13 ± 2)% E(MeV )
- (1.8 ± 0.3)%
7.5
Low energy electrons 5 2.5 0
0
10
20
30
40
50
60
70
80
Energy (MeV) CERN-SPSC - Sept 3, 2002
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Pi zero candidate (preliminary) •Reconstruction of γ-showers 158 MeV θ = 141o Minv = 650 MeV
752 MeV 140 MeV
θ = 25o Minv =140 MeV
Collection view Run 975, Event 151 CERN-SPSC - Sept 3, 2002
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An undeground observatory for rare processes
CERN-SPSC - Sept 3, 2002
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LNGS Hall B
CERN-SPSC - Sept 3, 2002
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The Basic Layout of the T1200 unit
Shock Absorbers
CERN-SPSC - Sept 3, 2002
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ICARUS detector configuration in LNGS Hall B (T3000) First FirstUnit Unit T600 T600++ Auxiliary Auxiliary Equipment Equipment
≈ 35 Metres
CERN-SPSC - Sept 3, 2002
T1200 T1200Unit Unit (two (twoT600 T600 superimposed) superimposed)
T1200 T1200Unit Unit (two (twoT600 T600 superimposed) superimposed)
≈ 60 Metres
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K + [AB] → µ + [BC] → e +[CD]
Proton decay
K+
65 cm
µ+
_
e+
e+
Run 939 Event 46
53 cm
p → K+ νe
µ+ K+ p=425 MeV CERN-SPSC - Sept 3, 2002
40
Particle identification (I)
dE/dx in 3 ton
120 14
Wires pitch = 5mm Noise = 20 keV
(a)
77 % of kaons inside, no pions
(b) 100
12
dE/dx (MeV/cm)
kaons 10
80
Kaons
pions
8
60
Pions
6
40 4 2 0
kaons decaying in flight
20
0
5
10
15
Range (cm)
20
25
0
-1
-0.5
0
0.5
1
1.5
2
2.5
3
Distance from the fit function (MeV)
Energy loss profile along kaon and pion tracks and distribution of the distance from the kaon fit function along pion and kaon tracks. CERN-SPSC - Sept 3, 2002
41
Particle identification (II)
dQ/dx (counts/wire)
Particle id. by dE/dx vs range dE/dx in 50 liter in the ICARUS 50 liter LAr TPC
dE/dx in T600
300
250
Run 939 Event 46
200 Proton dE/dx
150
K+
100 Pion dE/dx
µ+
50
0
0
2
CERN-SPSC - Sept 3, 2002
4
6 8 10 Range from end point (cm)
42
Proton decay: direct comparison with SuperK
SuperK results compiled by M. Goodman for NNN02, January 2002
O
O
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 corner In 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 to SuperK 22.5 kton
CERN-SPSC - Sept 3, 2002
43
SuperK e+π0 final state candidate
1997-09-24 12:02:48 : cut by SuperK because compatible with background
Particle momentum thresholds in Water: Water •Electron 0.6 MeV/c •Muon 120 MeV/c •Pion 159 MeV/c •Kaon 568 MeV/c •Proton 1070 MeV/c
CERN-SPSC - Sept 3, 2002
44
210 cm
70 cm
pe=474 MeV
e+
Proton decay p → e+ π 0
pπ0=417 MeV
2γ γ
γ
Missing momentum 150 MeV/c, Invariant mass 901 MeV
Not cut by ICARUS because of no background !
CERN-SPSC - Sept 3, 2002
45
Proton decay (II): existing SuperK results
? >4σ
O O O
Table presented by M. Goodman @ NNN02, Note that many are preliminary. January 2002 Many in the range of a few 1032 years Backgrounds are round the corner and not well understood ! ´ p→eK0 with K0 → ππ has excess of 6 vs 1 expected ´ Taking sum of all other proton channels one gets 1 seen for 5.2 expected ! ´ Backgrounds for neutron decays unsatisfactory
CERN-SPSC - Sept 3, 2002
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Proton decay: ICARUS expected sensitivities
O O O O
Extremely low backgrounds Inclusive analyses accessible Relevant results for few kton × year exposure already Expected range in few 1032 years after 5 kton × year exposures.
CERN-SPSC - Sept 3, 2002
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Atmospheric neutrinos O
O
Present situation: ´ SuperK will resume this year with 50% coverage ´ ICARUS will look with a completely new technique to such astrophysical source The atmospheric neutrino analysis in ICARUS will be characterized by ´ An unbiased, systematic-free observation whereas
SuperK is in practice limited to single-ring CC events
All other analyses rely on MC to extract signals (e.g. “NC enriched sample”, τappearance neural net based, …) ´ An excellent energy and angular reconstruction ´ Experimental and theoretical advances in prediction of the atmospheric neutrino rates which will match the improved measurements possible with ICARUS
Expertise within the Collaboration
Expect improvements in:
+ Low energy events + Clean electron sample + All final states, and with neutrino and antineutrino statistical separation + Neutral currents
CERN-SPSC - Sept 3, 2002
48
Atmospheric rates O
Mass is not the only issue!
CERN-SPSC - Sept 3, 2002
49
Atmospheric νµ interaction, Eν=1.73 GeV
90 cm
240 cm
µp
Atmospheric νe interaction, Eν=0.730 GeV
65 cm
50 cm
ep CERN-SPSC - Sept 3, 2002
50
Reconstruction of atmospheric neutrinos O
O
Containment ´ ≈60% of νµ CC events are fully contained ´ Contained 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 identification Measurement of escaping tracks (mostly muons) can be performed in different ways ´ By multiple scattering
Exploit the momentum dependence of the scattering
σp/p ≈ 0.10 + 0.048ln(p[GeV]) for 5 meters long tracks ´ By precise measurement of the energy loss rate
Exploit the relativistic rise of dE/dx precisely determined by combining successive samples
σp/p ≈ 20-30 %
CERN-SPSC - Sept 3, 2002
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Muon momentum reconstruction by multiple scattering
Analysis on stopping muons in the T600
in T600
CERN-SPSC - Sept 3, 2002
52
Reconstructed L/E distribution 2 L P(να → ν β ) = sin 2θ sin 1.27∆m E -0.3652E-01 0.3098
350 300 250 200 150 100 50 0
Mean RMS
800
-0.4069E-01 0.2875
700 600 500 400 300 200 100
-1
-0.5
0
0.5
1
((L/E)MC-(L/E)meas)/(L/E)MC
0
-1
-0.5
0
0.5
1
Events for 25 kton x year
Mean RMS
400
After 10 years…
2
Events (arbitrary units)
Events (arbitrary units)
2
((L/E)MC-(L/E)meas)/(L/E)MC
Oscillation parameters: ´ ∆m232 = 3.5 x 10-3 eV2 ´ sin2 2Θ23 = 0.9 ´ sin2 2Θ13 = 0.1
O
Electron sample can be used as a reference for no oscillation case
40 30 20 10 0
0.5
1
1.5
2
2.5
3
3.5
4
Log10(L/E)
Events for 25 kton x year
O
50
0
∆(L / E) RMS ≈ 30%
Electrons
60
140
Muons
120 100 80 60 40 20 0
0
0.5
1
1.5
2
2.5
3
3.5
4
Log10(L/E) CERN-SPSC - Sept 3, 2002
53
Astrophysical low energy neutrinos: solar and supernovae 0.225
57
Neutrinos(x 10 )
Supernova neutrino energy spectra νe 0.2 0.175 0.15
-
-
νµ+ντ+νµ+ντ 0.125 0.1 0.075
-
νe 0.05 0.025 0
0
10
20
30
40
50
60
Eν (MeV)
CERN-SPSC - Sept 3, 2002
Bahcall, http::/www.sns.ias.edu/~jnb
54
Low energy reactions in Argon O
Elastic scattering from neutrinos (ES) φ(νe)+0.15 φ(νµ + ντ)
O
νe + Ar→ K + e 40
40
*
−
Elastic scattering from antineutrinos (ES) φ(νe)+0.34 φ(νµ + ντ)
O
−
Electron-neutrino absorption (CC) φ(νe) Q=5.885 MeV
O
νx + e → ν x + e −
−
νx + e → ν x + e
Electron-antineutrino absorption (CC) φ(νe) e Q≈8 MeV
CERN-SPSC - Sept 3, 2002
−
ν + Ar→ Cl + e 40
40
*
+
55
ICARUS and the CNGS beam (I) O
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
O
The ICARUS physics program will be enriched by CNGS oscillation searches.
O
The ICARUS collaboration has already contributed to the design and optimization of the CNGS beam.
CERN-SPSC - Sept 3, 2002
56
ICARUS and the CNGS beam (II) O
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 JHFSK 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.
CERN-SPSC - Sept 3, 2002
57
ICARUS-CNGS experiment
O
O
O
Detector configuration ´ T3000 ´ Active LAr: 2.35 ktons 5 years of CNGS running ´ Shared mode ´ 4.5 x 1019 p.o.t./year 280 ντ CC expected for ∆m223=3 x 10-3 eV2 and maximal mixing
CERN-SPSC - Sept 3, 2002
Process
Expected Rates
νµ CC
32600
νµ CC
652
νe CC
262
νe CC
17
ν NC
10600
ν NC
243
ντ CC, ∆m2 (eV2) 1 x 10-3
31
2 x 10-3
125
3 x 10-3
280
5 x 10-3
750 58
CNGS Beam Profile Measurement
Events/2GeV/year
νµ energy beam profile for a T600 + T1200 detector configuration
2400 events/year
140
νµ CC simulated Evis νµ CC measured Evis
120
1 year = 4.5x1019 pots (CNGS official “shared” mode)
100
80
Average resolution on total visible energy: ≈10%
60
40
20
0
0
5
CERN-SPSC - Sept 3, 2002
10
15
20
25
30
35
40
45
50
Evis (GeV)
59
A. External muon spectrometer O
O
O
O
Already in 1999, the Collaboration had put forward the possibility to complement the liquid Argon imaging by an external device capable of magnetic analysis of escaping muons. Physics motivation: ´ Measure the muon charge via magnetic analysis ´ Online beam energy spectrum monitoring ´ Kinematical properties of closed νµ CC events
Direct measurement of background for τ searches ´ Improve 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 CERN-SPSC - Sept 3, 2002
60
Artist view spectrometer
ν
Muon spectrometer
CERN-SPSC - Sept 3, 2002
61
Basic Magnet Parameters
CERN-SPSC - Sept 3, 2002
62
420 cm
CNGS νµ interaction, Eν=26 GeV
130 cm
µ–
Vertex : 3 π0 , 1p, 3γ, 1µ
80 cm
300 cm
CERN-SPSC - Sept 3, 2002
CNGS νµ interaction, Eν=21.3 GeV
Vertex: 3π,5p,9n,3γ,1µ 63
CNGS ντ interaction, Eν=18.7 GeV
280 cm
105 cm
e-, 9.5 GeV, pT=0.47 GeV/c
τ-
→
e- +
_
ν e + ντ
290 cm
120 cm
eV/c G 6 1 . 1 = p e- , 15 GeV, T
_
Vertex: 1π0,2p,3n,2 γ,1e-
CNGS νe interaction, Eν=16.6 GeV CERN-SPSC - Sept 3, 2002
64
Event kinematics reconstruction
120
Mean RMS
Argon
100
Missing PT Events
Events
Evisible 16.24 6.553
No quenching
80
10
Mean RMS
2
0.4184 0.2638
Argon No quenching
60
10
40 20 0
1
0
5
10
15
20
25
0
30
0.2
0.4
0.6
0.8
1
1.2
TMG-doped Argon
100
Mean RMS
Events
Events
120
16.68 6.529
No quenching
80
1.4
1.6
1.8
2
Missing PT (GeV)
Evisible (GeV)
10
Mean RMS
2
0.3947 0.2590
TMG-doped Argon No quenching
60
10
40 20 0
1
0
5
10
15
20
25
30
Evisible (GeV)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Missing PT (GeV)
≈ 410 MeV CERN-SPSC - Sept 3, 2002
65
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
νµ→ ντ νµ→ νe
ντ+Ar→τ+jet; τ→ Charged current (CC)
eνν µνν − 0 h nh ν h − h + h − nh 0ν
18% 18% 50% 14%
νe+Ar→e+jet Charged current (CC)
CERN-SPSC - Sept 3, 2002
66
τ→e search: 3D likelihood A simple analysis approach: a likelihood method based on 3 variables
O
O
3 variables ´ Evisible, PTmiss, ρl≡PTlep/(PTlep+ PThad+PTmiss) Exploit correlation between them
LS ([Evisible, PTmiss, ρl]) (signal)
LB ([Evisible, PTmiss, ρl]) (νe CC background) ´ Discrimination given by
40
19
p.o.t./year)
35
νe CC + ντ CC
30
νe CC
25
ντ CC, τ→ e
Vertex cuts applied
20
15
10
5
Overflow
¤
lnλ ≡L([Evisible, PTmiss, ρl]) = Ls / LB
Events/12 kton x year
5 T600 modules, 5 years CNGS (4.5 x 10
0
-2
0
2
4
6
8
10
lnλ
lnλ More sophisticated approaches (e.g. neural net,…) under study. CERN-SPSC - Sept 3, 2002
67
τ→e search: 3D likelihood summary 5 year “shared”CNGS running T3000 configuration
Maximum sensitivity
CERN-SPSC - Sept 3, 2002
68
νµ→ ντ appearance search summary O O
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.
O O O
Several decay channels are exploited (golden channel = electron) (Low) backgrounds measured in situ (control samples) High sensitivity to signal, and oscillation parameters determination
CERN-SPSC - Sept 3, 2002
69
Oscillation parameters determination CNGS + ATMOSPHERIC combined data
∆ m232 (eV2)
0.006
5 years exposure combining beam and atmospheric neutrino events (within the same detector!)
(90% C.L.)
0.005
90% C.L. SuperK allowed
0.004
0.003
0.002
δ(∆m 2 ) ICARUS 1 T600 + 2 T1200 modules Five years exposure
0.001
0
0.2
0.4
0.6
0.8
Dm
2
ª 10%
1
sin2 Θ23 CERN-SPSC - Sept 3, 2002
70
Search for subleading νµ→νe (I) O
The emerging scenario: ´ | ∆m221 | =(4÷12)×10–5 eV2 ´ tan2θ12 = 0.32÷0.51 ⇒ 30°
