The ICARUS Projecticarus.lngs.infn.it/serwer/conferences/Uppsala.pdf · André Rubbia, ETH/Zürich, ICARUS Collaboration, 11/2/01 Neutrino and rare process physics The performance

Andr Rubbia, ETH/ Z rich, 11/2/01

The ICARUS Project

André RubbiaETH Zürich

8th-10th February, 2001

SNOW in Uppsala

ItalyAquila, LNGS, Milano, Padova, Pavia, Pisa, Torino

ChinaIHEP

SwitzerlandETH/Zurich

USAUCLA

CERN

PolandKatowice, Krakow, Warszawa,

Wroclaw

André Rubbia, ETH/Zürich, ICARUS Collaboration, 11/2/01

The IC

AR

US

Collaboration


Neutrino and rare process physics✯ The performance of a neutrino detector is proportional

to its total mass and also to its geometricalgranularity with which the events can be reconstructed.

�Atmospheric neutrinos:− ≈1000 atm CC events / year

− ≈≈≈≈5 ντ CC /year from oscillations

�Solar neutrinos:

− 17500××××f8B solar neutrinos / year @ E > 5 MeV

�Neutrinos from CERN (CNGS):

−13600 νµ CC per 4.5×1019 pots @ L = 730 km

�Neutrino factory:

− 1200 νµ CC per 1020 µ @ L = 7400 km

�Number of targets for nucleon stability:

− 3 × 1033 nucleons ⇒ ττττp (1032 years) > 6 ×××× T(yr) ×××× εεεε @ 90 C.L.

What we get for 5 ktons:What we get for 5 ktons:

γγγγνννν

A bonus!


ICARUS liquid argon imaging TPC (I)✯ The LAr TPC technique is based on the fact that ionization electrons can drift

over large distances (meters) in a volume of purified liquid Argon under a strongelectric field. If a proper readout system is realized (i.e. a set of fine pitch wiregrids) it is possible to realize a massive "electronic bubble chamber", with superb3-D imaging.

40 cm

40 c

mW

ires

Drift

"Bubble" size ≈ 3 x 3 x 0.2 mm3

Energy depositionmeasured for eachpoint


✯ Detect electrons produced by ionizing tracks crossing the LAr

v–

v+

+

–

Ionizing track

V

i0

Ed

d

d

p

Ionizing track

1st Induction wire / Screen grid

2nd Induction wire grid (x view)

Collection wire grid (y view)

e-

Char

ge

Drift timeA

B

C

Signals induced

Char

ge

Drift timeA B

C

Drift

Electron-ion pairs are producedElectrons give the main contribution tothe induced current due to the much larger mobility

I0 = e(v+ + v-)/d

A set of wires at the end of the drift give a sampling of the trackNo charge multiplication occurs near the wires Ë electrons can be used to induce signals on subsequent wires planes with

different orientations ⇒ 3D imaging

E = 500 V/cm

ICARUS liquid argon imaging TPC (II)


ICARUS liquid argon imaging TPC (III)Detector is continuously sensitive, thus allowing to easily

simultaneously collect atmospheric, CNGS and other rare events...

Time -- drift

Rea

l eve

nt fr

om 1

5 to

n


CERN ν-beam

νµ + n → µ − + p

128

read

out w

ires

2.54

mm

wire

pitc

h

ICARUS-CERN-Milano

(Chamber located in front of NOMAD detector)

collection view time (400 ns/sample)46 cm max. drift distance

Neutrino event in 50 liter LAr TPC (1998)


ICARUS: a graded strategy

✔ After several years of R&D and prototyping, the ICARUS collaboration is nowrealizing the first 600 ton module, which will be installed at Gran Sasso in theyear 2001.

Small-scaleprototypes 15 ton

T600

→ Air Liquide for Cryostat and Argon purification

→ BREME Tecnica for internal detector mechanics

→ CAEN for readout electronics

Cooperation with specialized industries:

We are here!

Lab activities:

2x300 tonT1400 (?)

≈≈≈≈4x300 tonor 1x1400 ton


ICARUS 15 ton (10m 3) prototype (1999-2000)

✯ A major step of the R&D program hasbeen the construction and operation ofa 10m3 prototype

� Test of the cryostat technology

� Test of the “ variable-geometry ” wire

chamber

� Test of the liquid phase purification

system

� Test of trigger via scintillation light

� Large scale test of final readout

electronics

T15 installation @ LNGS (Hall di Montaggio)

➜ First operation of a 15 ton LAr massas an actual “detector”


Cryostat

Cryo. pump

LN2 exchanger

Control


Cooling 15 ton prototype March ‘99

✖Confirmation of thefunctionality of the variablegeometry mechanics

100

1000

-50 0 50 100 150 200 250

Lifetime evolution

Life

time

(µµµµ s

)

Elapsed Time (hours)

Pump OFF

Pump ON

✖The electrons lifetime, afterabout 4 days of recirculation, wasbetween 2 ms to 3 ms.

LAr purityTemperature / Wire stretching


Top View

Lateral View

Internal Volumes Layout

Imaging region (35 cm drift)

External trigger

cathode

wires


• Just after LAr filling: τ ~ 100µs, according to expectations based on residual leak

rates ( 10-5 mbar/s).

• In a few days of LAr pump operation: τ > 2 ms

Slow ττττ degradation (GAr recirculation off)

Electron Lifetime Measurements


Tracks in 15 ton prototype

Drift

Wire

s

40 cm

76 c

m

DriftW

ires

10m3 Moduleat LNGS

Cosmic Ray tracksrecorded during the10 m3 operation


The ICARUS T600 module

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Number of independent containers = 2Single container Internal Dimensions: Length = 19.6 m , Width = 3.9 m , Height = 4.2 mTotal (cold) Internal Volume = 534 m Sensitive LAr mass = 476 ton

Number of wires chambers = 4Readout planes / chamber = 3 at 0° , ± 60° from horizontalMaximum drift = 1.5 mOperating field = 500 V / cmMaximum drift time ≈ 1 msWires pitch = 3 mmTotal number of channels = 58368

2 independent aluminum containerseach one transportable inside the GS Laboratory

External insulation layer (400 mm)

LN2 cooling circuit

Signal feedthroughs

HV feedthroughs

Under construction

3


T600 assembly schedule

✯ Completed site preparation in Pavia for the T600 cryostat (Nov 1999 )➜ “clean room”, “assembly island”, floor, ...

✯ Delivery of the 1st cryostat by AirLiquide (Feb 2000)➜ Successful vacuum tightness and mechanical stress tests

✯ Beginning of assembly of the internal detector mechanics (Mar 2000)

✯ Completion of assembly and positioning of inner detector frames (Jul 2000 )

✯ Installation of 30000 wires + signal cables (Jul 2000-Oct 2000 )

✯ Delivery of the 2nd cryostat of AirLiquide (Aug 2000 )➜ Successful vacuum tightness and mechanical stress tests

✯ Installation of scintillation light and all slow control devices (Jul 2000-Dec2000)

✯ H.V. and field electrodes system installation (Oct 2000- Jan 2001 )

✯ Installation of the 48 electronic racks on top of dewar (Dec 2000-ongoing )✯ Installation of external heat insulation (for both dewars) and LAr and LN 2

cryogenic circuits (Dec 2000-Jan 2001 )

✯ Semi-module now ready to be sealed.


First half-module delivery in Pavia (Feb 29, 2000)


Cryostat

Assembly of the T600 internal detector (Mar-Jul 2000)

Dirtyobserver

Cleanworkers

Internaldetector


Second half-module during the vacuum test (Jul 2000)


Vacuum curve

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

0.01000 0.10000 1.00000 10.00000 100.00000

Pumping Time (hr )

Ab

solu

te

pre

ssu

re

(mb

ar)

Primary Vacuum (speed = 72 m 3/ h r )

Turbomolecular pumping (speed = 2000 lt/sec)

Vacuum Tests - Second half-module


Walls Displacement s

- 3 5

- 3 0

- 2 5

- 2 0

- 1 5

- 1 0

- 5

0

5

1 0

1 5

0.00E+00 2.00E+02 4.00E+02 6.00E+02 8.00E+02 1.00E+03 1.20E+03 1.40E+03 1.60E+03

Absolute Pressure (mbar)

Dis

pla

cem

en

t (m

m)

D1 (mm)D2 (mm)D3 (mm)D4 (mm)D5 (mm)D6 (mm)D7 (mm)D8 (mm)D9 (mm)

Dewar behaviour under inner pressure change

overpressure

vacuum


Second half-module (delivered Aug 2000)

Thermal floor

Thermal insulation panels


Nomex honeycombpanels (heat insulation)

Dewar

Readoutelectronics


Installation slow control devices (Jul 2000)

Wire stretchingsensor


Wire installation in T

600 internaldetector (Jul-O

ct 2000)


and one PMT

The three wire planes at 0°,±60° (wire pitch = 3mm)


Wires crossing the spacers (wire pitch = 3mm)


Wire ChamberSide A

Wire ChamberSide B

Drift distance1.5 m

T600 - Completed Internal Detector view


Drift distance1.5 m

Hor

izon

tal w

ires

read

out c

able

s–75kVRace-track

E

Drift H.V. and field electrodes system


Slow control system and scintillation light detection✯ Several instrumentation , most of it custom designed to work at LAr temperature in high

purity environment, has been built tested and installed:

➜ LAr Purity monitors

➜ High precision LAr level meters

➜ Position meters for the wires tensioning springs and for the container walls

➜ Temperature probes

✯ Detection of LAr scintillation light (VUV λ=128 nm, attenuation length in LAr ≈90cm,

1÷2×104 γ per MeV deposited)

➜ Provide help for triggering and T0 measurement .

➜ Bare PMT’s immersed in LAr with wavelength shifter deposited on the glass window

– Test and qualification of PMT at LAr temperature:8 inches EMI PMTs with special treatedbialkali photocathode to work at cryogenic temperature.

– Choice of most efficient wavelength shifter (TPB = TetraPhenylButadiene), depositionmethod (spray), aging properties, pollution of LAr, etc.


Position meter PMT

Purity Monitors

Wires before tensioning

Slow control sensor (behind wire planes)


8” PMT coated with TPB

Scintillation light collection(in total 20 PMTs on detector walls)



chimneys

Electronicrack

Readout electronic installation on top of dewar (Dec 2000-now)


Readout electronic installation on top of dewar (Dec 2000-now)

Digital

Analog


Man-hole (after sealing, the only way to get inside!)


✯ The ICARUS T600 detector

➜ has a physics program of its own, immediately relevant for neutrino oscillationphysics: solar+SN neutrinos, atmospheric neutrinos

➜ Though with limited statistics, due its relatively small mass, compared to the standardfor underground detectors set by the operating SuperKamiokande.

✯ However, the T600 should also be considered as one more step towards largerdetector masses.

➜ solving technical issues associated with actual operation of a large mass LAr devicein an underground site (LNGS Tunnel).

➜ fully establish the imaging, PID, calorimetric energy reconstruction capabilities ofREAL events, during steady detector operations

➜ In situ proof of actual physics performance of this novel detector technique, inparticular measurement of backgrounds, extrapolable to larger mass detectors

✯ Physics issues for both present and future LAr detectors: Atmospheric ννννSolar+SN ννννCNGS+Nufactory ννννp decay

Perspectives of ICARUS


Proposed setup ICARUS 5kt in LNGS Hall B

ICARUS T600

Two possible options:A) ≈8 x T600B) 4 x T1400 (better for physics)


Muon bending measurement

L

8 m

µ

✯ We consider a design in which the muon escaping theliquid Argon is bent by a magnetized piece of iron

B=2.0 T, L�iron� = 2.5 m�

0

25

50

75

100

125

150

175

200

5 10 15 20 25 30 35 40µ momentum (GeV)

An

gle

(m

rad

)

Angle due to bending in magnetic field�

Angle due to multiple scattering�

B = 2 Tesla, L = 2.5 m

Bθ

The bending angle θθθθ is measured withthe tracks observed in two

subsequent liquid argon module

Bending in field

Multiple scattering

16 m

∆∆∆∆p/p ≈≈≈≈ 25%

Charge confusion: ~10-4


The νννν oscillation framework: Three flavor mixing!

P P PCP CP( ) ( ) ( )ν ν ν ν ν να β α β α β→ = → ± →/ /

P JCP jk jkj k

= −>∑δαβ αβ4 2Re sin ∆

∆∆

jkjkm L

E=

1 27 2.

ννν

ννν

µ

τ

µ µ µ

τ τ τ

e e e eU U U

U U U

U U U

=

1 2 3

1 2 3

1 2 3

1

2

3

∆∆∆∆m2jk in eV2, L in km,

E in GeV

Weak eigenstates

Mass eigenstates

ν1

ν2

ν3νµ

ντ

νe

P JCP jk jk jkj k

/ />

= ∑4 Im sin cos αβ ∆ ∆

J U U U Ujk k k j jαβ α β α β= * *

CP-conservingCP-violating

Mixing strength

Oscillatory pattern

(—) (—) (—) (—) (—) (—)

In general, the oscillation pattern may be complicated and involve a combination of transitions to

ννννe, ννννµµµµ, ννννττττ and by symmetry with quark sector it is natural to expect CP violation at some level.


Three family oscillations

Ue3➨ Parameterization la CKM :

∆m232 ≈ ∆m2

31≈3x10–3 eV2, θ23≈45°Atmospheric anomaly:

Solar deficit: ∆m212, θ12 , θ23

➨ Current standard mass and mixing assignment:

P P( ) ( )?

ν ν ν να β α β→ ≠ →}

δ≠0?

θ13 (small)

ν νµ τ→

ν νµ τe → /

ν νµ → e ν ντe →


3 flavor mixing analysis of SuperKamiokande

K. Nakamura, NUFACT00, Monterey(USA), May 2000

PRELIMINARY

Atmospheric neutrinosanalysis


Solar neutrinos

M.B. Smy, NOON2000, Tokyo(Japan), Dec 2000No smoking gun ?


�Atmospheric neutrinos�Improvements over existing detection technique

—Detection down to production thresholds—Complete event final state reconstruction—Identification all neutrino flavors—Identification of neutral currents

�Excellent resolution on L/E reconstruction

�Direct ττττ appearance search

�Neutrinos from CERN�Search for ννννµ →→→→ ννννττττ

�Search for ννννµ →→→→ ννννe

�Solar neutrinos�Energy threshold: 5 MeV�Large statistics, high precision measurements�Experimental signal ν νe ee e+ → +νe Ar e K+ → +40 40 *

Absorption Elastic

ICARUS physics potential (I)

∆m232, θ23

∆m212

∆m232, θ23 , θ13

∆m212, θ12


�Proton decay�Large variety of decay modes accessible

⇒⇒⇒⇒ study branching ratios free of systematics

�Background free searches⇒⇒⇒⇒ linear gain in sensitivity with exposure

�Neutrinos “factory”�Precise measurement of ∆∆∆∆m2

23, ΘΘΘΘ23, ΘΘΘΘ13

�Matter effects, sign of ∆∆∆∆m223

� First observation of ννννe →→→→ ννννττττ

�CP violation

ICARUS physics potential (II)

∆m232, θ23 , θ13

∆m232>0 or ∆m2

32<0 ?

Unitarity of mixing matrix

δ≠0 ?

mm

Mheavyν

?

=}

Physics at Unificationscales?


Solar neutrinos detection in ICARUS

❖ Two reactions can be measured independently:

ν νx xe e+ → +− − νe Ar K e+ → + −40 40 *

Elastic scattering onatomic electron

νννν absorption onArgon nuclei

❖ Signature:❖ Primary electron track❖ Absorption: surrounded by low energy secondary tracks (40K*de-

excitation).❖ Prototype setup: electron track visible down to kinetic T=150 KeV❖ Electron track threshold = 5 MeV (needed to reduce background

contribution and to establish the e- direction in elastic scattering).❖ Sensitive to 8B component of the solar spectrum.


Radioactive source: 6 MeV γγγγ’s



Signal selection

✯ Elastic events:➜ Angular distribution of the electron

peaked in the solar ν direction:

✯ Absorption events:➜ Electron track directions can be

considered isotropically distributed

α = 25˚

ε = 72%

The off-line selection can be done in terms of the energyof the main electron and the correlation betweenmultiplicity and energy of the associated tracks.


Solar νννν’s background events

Naturalradioactivity

Spontaneous fission orSpontaneous fission or((αα ,n) reactions,n) reactions

Captures in the detectorCaptures in the detector((4040Ar, Ar, 2727Al, Al, 5656Fe,…)Fe,…)

n flux γγγγ-rays e-

energies inenergies in

the the 88B rangeB range

Y(cm)�

X(c

m)�

n/cm2/s capt/cm2/s

Y(cm)

X(c

m)

Neutronshield

(Full FLUKAsimulation)

≈7400 captures/year in500 ton fiducial ≈150 /year with Ee>5 MeV


Solar neutrino rates and sensitivity

Events per year for a 600ton detector

Te (MeV) Neutrons

0.0 7400

1.0 3404

2.0 1554

3.0 696

4.0 318

5.0 144

6.0 66

7.0 30

8.0 13

Events/year

Elastic channel Background

2126

Absorption channels Background

759 26

470 ton fiducial, allcuts imposed

RN N

N N

EStheoryES

ABStheoryABS≡

/

/

ES=elastic scattering

ABS=absorption events

ν νx xe e+ → +− −

νe Ar K e+ → + −40 40 *

∆R R kt yr kt yr kt yr/ %( ), %( ), %( )≈ × × ×7 1 5 2 4 4

10 10 10 10 10-4 -3 -2 -1 0

10

10

10

10

10

10

10

10

10

10

10

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0.950.98

0.98

0.990.99

0.99

0.99

0.99

1

1.08

1.08

1.08

1.08

1.2

1.3

1.51.92.2

5

10

20

57

MS

W -

LO

W

JustSo

MSW - SMA

MS

W -

LM

A

sin2 2 θ

∆ m

2 (eV

)2

(a)


Supernova neutrinos detection in ICARUS

✯ ICARUS can detect neutrinos coming from stellar collapses in ourGalaxy via 2 processes:

➜ Elastic scattering(flavor independent)

➜ Absorption on argon

ν νx xe e+ → +− −

νe Ar K e+ → + −40 40 *

Expected events from a stellarcollapse occurred at 10 kpc

600 ton 5 kton 30 kton

8 70 400

Nv = ×8 1057


Atmospheric neutrinos

π,Kµ

e

Earth

µ�

µ�

p,He,...

p,He,...

νµ

νµ

hadronic cascade + decays

almost isotropic source(geomagnetic effects)

0.4 < Eν < 1 GeV at Gran Sasso

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

-1 -0.5 0 0.5 1

3 dim

1 dim

cosθ

ν/cm

2 /sec

/sr/

GeV

νµ 0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

-1 -0.5 0 0.5 1

3 dim

1 dim

cosθ

νµ-

0.01

0.0125

0.015

0.0175

0.02

0.0225

0.025

0.0275

0.03

-1 -0.5 0 0.5 1

3 dim

1 dim

cosθ

ν/cm

2 /sec

/sr/

GeV

νe 0.008

0.01

0.012

0.014

0.016

0.018

0.02

0.022

0.024

-1 -0.5 0 0.5 1

3 dim

1 dim

cosθ

νe-

Simulation based on FLUKA interaction and transport code(extensively benchmarking against data)3D representation of Earth and atmosphereGeomagnetic effects includedAll relevant physics taken into account: energy losses, polarized decays


90 cm

90 c

m Eν = 370 MeV

Pµ = 250 MeV

Tp = 90 MeVµ

p

Atmospheric ννννµµµµ CC

e

(simulated event)

Atmospheric v’s

ννννµ Q-el. interaction


100 cm

90 c

m

Eν = 450 MeV

Pe = 200 MeV

Tp = 240 MeVp

e

Atmospheric v

ννννe quasielastic interaction

(simulated event)

Atmospheric ννννe CC


Events/year

NUX �σν/E�ν , isoscalar�

0

0.2

0.4

0.6

0.8

1

1.2

10-2

10-1

1 10 102

Eν (GeV)

σ/E

TotalQEDISCharm

Atmospheric neutrino rates (5 kt x year)(nux)

Nuclear effectsfully embedded in FLUKAnuclear model


0�

50�

100�

150�

200�

250�

300�

350�

400�

-1� -0.5� 0� 0.5� 1�

Mean�

RMS�

-0.3652E-01�

0.3098�

((L/E)�MC�-(L/E)�meas�)/(L/E)�MC�

Eve

nts

(arb

itrar

y un

its)�

0�

100�

200�

300�

400�

500�

600�

700�

800�

-1� -0.5� 0� 0.5� 1�

Mean�

RMS�

-0.4069E-01�

0.2875�

((L/E)�MC�-(L/E)�meas�)/(L/E)�MC�

Eve

nts

(arb

itrar

y un

its)�

L/E distribution

✯ Oscillation parameters:➜ ∆∆∆∆m2

32 = 3.5 x 10-3 eV2

➜ sin 2 2ΘΘΘΘ23 = 0.9

➜ sin 2 2ΘΘΘΘ13 = 0.1

✯ Electron sample can be usedas a reference for nooscillation case

0�

10�

20�

30�

40�

50�

60�

0� 0.5� 1� 1.5� 2� 2.5� 3� 3.5� 4�Log�10�(L/E)�

Eve

nts

for

25 k

ton

x ye

ar�

0�

20�

40�

60�

80�

100�

120�

140�

0� 0.5� 1� 1.5� 2� 2.5� 3� 3.5� 4�Log�10�(L/E)�

Eve

nts

for

25 k

ton

x ye

ar�

Electrons

Muons

25 kt yearP mL

E( ) sin sin .ν ν θα β→ =

2 2 22 1 27∆

∆( / ) %L E RMS ≈ 30


CNGS neutrino beam

CERN Gran Sasso

CERN Neutrino Beam in the Direction of Gran Sasso

earth

Distance = 732 Km

Earth

radi

us =

638

0 Km 10.5 km below ground Planned beam commissioning: May 2005

CERN 98-02 - INFN-AE/98-05CERN-SL/99-034(DI) - INFN/AE-99/05

The expected νe and ντ contamination of the CNGS beam are of the

order of 10–2 and 10–7 respect to the dominant νµ.

ννννττττ? ννννe?

ννννµµµµ


✯ Primary protons: 400 GeV; 4x2.3x10 13 p/cycle; 26.4 s/cycle✯ Pots per year: 4.5x1019 pots “shared”; 200x0.75 days/year

✯ Optimized for

✯ 7.6x1019 pots/yr “dedicated”CERN 98-02 - INFN-AE/98-05; CERN-SL/99-034(DI) - INFN/AE-99/05

CNGS event rates

νµ CC events events spectrum@LNGS

νννν ττττ CC

eve

nt

rate

s

N E E E dECCτ ν νφ σ

µ τ∝ × −∫ ( ) ( ) 2

No

osci

llatio

ns


CNGS events in 5 kton, 4 years running

θθθθ23 = 45°, θθθθ13 = 7°


eννBr ≈ 18%

ττττ→→→→ννννµµµµ→→→→ ννννττττCharged current (CC)

ννννττττ++++N→→→→ττττ+jet;

Charged current (CC)ννννe++++N→→→→e+jet

ννννµµµµ →→→→ννννττττ oscillations (I)

Background:

✯ Analysis of the electron sample

➜ Exploit the small intrinsic νe contamination of the beam

(0.8% of νµ CC)

➜ Exploit the unique e/π0 separation

470 νeCC

∆m eV2 3 23 5 10= × −. 110 events

Statistical excess visible before cuts ⇒⇒⇒⇒ this is the main reason for performingthis experiment at long baseline !

⇒


ννννµµµµ →→→→ννννττττ oscillations (II)

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35 40

νe� + �ντ CC�νe� CC�ντ CC�

Evisible (GeV)

Eve

nts

/20k

ton

x y

ear

Reconstructed energy

νe CC

signal

✯ Reconstructed visibleenergy spectrum of electronevents clearly evidencesexcess from oscillations intotau neutrino


ννννµµµµ →→→→ννννττττ oscillations (III)

νe CC 0

2

4

6

8

10

12

14

16

18

20

0 0.5 1 1.5 2 2.5 3

νe� + �ντ CC�νe� CC�ντ CC�

Missing PT (GeV)

Eve

nts/

20kt

on x

yea

r

Transverse missing PT

✯ Kinematical selection in order to enhanceS/B ratio

✯ Can be tuned “a posteriori”depending on the actual ∆m2

✯ For example, with cuts listed below,reduction of background by factor 100 fora signal efficiency 33%


e/ππππ0 discrimination

electron ππππ0

0�

0.0005�

0.001�

0.0015�

0.002�

0.0025�

0� 5� 10� 15� 20� 25� 30� 35� 40� 45� 50�0�

0.0005�

0.001�

0.0015�

0.002�

0.0025�

0� 5� 10� 15� 20� 25� 30� 35� 40� 45� 50�

Wire number Wire number

GeV

GeV

Single m.i.p. Double m.i.p.

e ee

Wire pitch = 3 mm ¯ 0 .02 X0

0

50

100

150

200

250

300

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Ent

ries/

0.02

MeV

(ar

bitr

ary

norm

aliz

atio

n)

Energy deposited (MeV)

Single electrons vs Dalitz pairs20 wires

pitch = 3 mm

Dalitz pairs>99% with Edep > 1MeV

single electrons91.4% with Edep < 1MeV

¯10cm

Combined rejection: dE/dx +photon converted within 3 cmof vertex: > 500


L = 732 Km �∆m�2� = 3.5 x 10�-3� eV�2� �Θ23� = 45�o� �Θ13� = 7�o�

10-1

1

10

10 2

10 3

0 2 4 6 8 10 12 14Elepton (GeV)

Eve

nts/

20kt

on x

yea

r

All�

νe� CC�

Oscillated �νµ→ �νe�

Oscillated �νµ �→ �ντ

NC�

νe� CC + Oscillated �νµ �→ �ντ

ICANOE at CNGS

Evis < 20 GeV

ννννe CC versus νννν NC discrimination (I)

L = 732 Km �∆m�2� = 3.5 x 10�-3� eV�2� �Θ23� = 45�o� �Θ13� = 7�o�

10

10 2

10 3

0 2 4 6 8 10 12 14Elepton (GeV)

Eve

nts/

20kt

on x

yea

r

All�

νe� CC�



NC�


ICANOE at CNGS

Evis < 20 GeV

γ converting within 3 cm (10 samples) from primary vertexconsidered as electron candidate

NC

NO dE/dxinformation used

dE/dx information usedSingle vs double m.i.p.algorithm provides >500rejection factor


L = 732 Km �∆m�2� = 3.5 x 10�-3� eV�2� �Θ23� = 45�o� �Θ13� = 7�o�

1

10

10 2

10 3

10 4

0 0.5 1 1.5 2 2.5 3Missing PT (GeV)

Eve

nts/

20kt

on x

yea

r

All�

νe� CC�



NC�


ICANOE at CNGS

Evis < 20 GeV and Ee > 1 GeVQlep > 0.3 GeV

L = 732 Km �∆m�2� = 3.5 x 10�-3� eV�2� �Θ23� = 45�o� �Θ13� = 7�o�

10-1

1

10

10 2

10 3

0 0.5 1 1.5 2 2.5 3Missing PT (GeV)

Eve

nts/

20kt

on x

yea

r

All�

νe� CC�



NC�


ICANOE at CNGS

Evis < 20 GeV and Ee > 1 GeVQlep > 0.3 GeV

ννννe CC versus νννν NC discrimination (II)

Additional discrimination powerprovided by event kinematics

NC rejection

NO dE/dx information used dE/dx information used


∆∆∆∆m232=3.5x10–3 eV2; sin22θθθθ23 = 1

Search for θθθθ13≠≠≠≠0

ICANOE4 years

P e( ) sin sinν ν θ θµ → = 213

223

2322 ∆

P( ) cos sinν ν θ θµ τ→ = 413

223

2322 ∆


0

10

20

30

40

50

60

70

0 5 10 15 20 25 30 35 40Evisible (GeV)

Eve

nts

/20k

ton

x y

ear

νe� CC + oscillated �νµνe� CC�Oscillated �νµ→ �νe�

Oscillated �νµ �→ �ντνe� CC + Oscillated �νµ �→ �ντ

L = 732 Km �∆m�2� = 3.5 x 10�-3� eV�2� �Θ23� = 45�o� �Θ13� = 7�o�

0

10

20

30

40

50

60

70

0 0.5 1 1.5 2 2.5 3Missing PT (GeV)

Eve

nts

/20k

ton

x y

ear

νe� CC + oscillated �νµνe� CC�Oscillated �νµ→ �νe�

Oscillated �νµ �→ �ντνe� CC + Oscillated �νµ �→ �ντ

ICANOE at CNGS

Evis < 20 GeV and Ee > 1 GeV

Transverse missing PTTotal visible energy

P e( ) sin sinν ν θ θµ → = 213

223

2322 ∆P( ) cos sinν ν θ θµ τ→ = 4

132

232

322 ∆

∆∆∆∆m232=3.5x10–3 eV2; sin22θθθθ23 = 1 ; sin22θθθθ13 = 0.05


10-4

10-3

10-2

10-1

10-3

10-2

10-1

1

↔νµ νe90% allowed

χ2 min

+ 4.6

νµ → ντ included, Θ23 = π/4

CHOOZ

sin2 2Θ13

∆m2 23

(eV

2 )Sensitivity to θθθθ13 in three family-mixing

Ο Sensitivity to νµ → νe

oscillations inpresence of νµ → ντ

(three family mixing)

Ο Factor 5 improvementon sin22θ13 at ∆m2 =3x10–3 eV2

Ο Almost two-orders ofmagnitudeimprovement overexisting limit at high∆m2


Nucleon decay search

Thanks to excellenttracking and particle

id capabilities

LAr unique tool for

Extremely efficientbackground rejection

High detection efficiency

Bias-free, fully exclusivechannel searches!

p→→→→e+ ππππ0000 decayp→→→→ννννK+ decay n→→→→ννννK0 decay

André Rubbia, ETH/Zürich, ICARUS Collaboration, 11/2/01 Exposure: 1000 kton x year

p→→→→e+ ππππ0 decay kinematics

0

20

40

60

80

100

0 0.2 0.4 0.6 0.8

π0 absorbed

π0 detected

Total Momentum (GeV)

N /

20 M

eV

0

100

200

300

400

500

0.4 0.6 0.8 1

π0 absorbed

π0 detected

Measured Energy (GeV)

N /

20 M

eV

≈45% π0 absorbed in Ar nucleus

Nuclear effects: pion absorption and rescattering included(FLUKA)

André Rubbia, ETH/Zürich, ICARUS Collaboration, 11/2/01 Exposure: 1000 kton x year

p→→→→K+νννν decay kinematics

At least we see the kaon!


Proton decay: expected backgrounds vs channel

ICARUS Proton Decay: Expected Backgrounds

1

10

10 2

10 3

1 10 102

103

p → e+ π0

p → e+ (π0)

p → K+ ν–

p → µ- π+ K+

p → e+ π+ π-

p → e+ π+ (π-)

p → e+ (π+ π-)

p → π+ ν–

p → µ+ π0

p → µ+ (π0)

Exposure (kTons × year)

Exp

ecte

d B

ackg

roun

ds (

# ev

ents

)

Channel # Bkg. events

( 1kTon × year )

p → e+ π0 0.002p → e+ (π0) 2.099

p → K+ ν–

0.001p → µ- π+ K+ 0.001p → e+ π+ π- 0.025

p → e+ π+ (π-) 1.257p → e+ (π+ π-) 5.945

p → π+ ν–

0.552p → µ+ π0 0.015

p → µ+ (π0) 5.829

p→e+π0

p→K+ν

p→e+X

1 Mton x yr

Extremely good exclusivesignal signatures

⇒ Excellent backgroundrejection

Discovery with a singleevent!

Nuclear effects in backgrounds: fullyembedded in FLUKA nuclear model


Sensitivity vs exposureICARUS: Limits on Proton Decay

1031

1032

1033

1034

1035

1 10 102

103

p → e+ π0

p → e+ (π0)

p → K+ ν–

p → µ- π+ K+

p → e+ π+ π-

p → e+ π+ (π-)

p → e+ (π+ π-)

p → π+ ν–

p → µ+ π0

p → µ+ (π0)

Exposure (kTons × year)

τ p/B

upp

er li

mit

at 9

0% C

L (

year

s)

Channel Efficiency (%) # Bkg. events

( 1kTon × year )p → e+ π0 37.5 0.002

p → e+ (π0) 14.15 2.099p → K+ ν

–97.15 0.001

p → µ- π+ K+ 99.2 0.001p → e+ π+ π- 22.4 0.025

p → e+ π+ (π-) 29.15 1.257p → e+ (π+ π-) 14.45 5.945

p → π+ ν–

39.75 0.552p → µ+ π0 40.95 0.015

p → µ+ (π0) 18.25 5.829

Nuclear effects in signal: fully embeddedin FLUKA nuclear model

p→e+π0

p→K+ν

Extremely good exclusivesignal signatures

⇒ Excellent backgroundrejection

Discovery with a singleevent!

1034

1035

10 kton x yr


Exposure needed to reach PDG limit

Given our poor knowledge of the physics at the GUT scale, weneed to look for all possible channels, in unbiased, free of

background searches.


µ− →e− νeνµνµ→νe→e− appearance

νµ disappearance

νµ→ντ→τ− appearance

νe disappearance

νe→ νµ→µ+ appearance

νe→ ντ→τ+ appearance

Plus their charge conjugates with µ+

beam

Neutrino factory

Ideal detector should be able tomeasure 12 different processes

�Detect: µ+, µ−, e, NC, τ

�Various baselines

�Various muon energies

O(1021) µ required


E�µ = 30 GeV, L = 7400 km, 10�20� �µ-� decays�

0

20

40

60

80

100

120

0 5 10 15 20 25 30 35 40Evisible (GeV)

dN/d

Eν (

ν e C

C e

vent

s/1.

6GeV

per

10

kton

)

Anti-�νe�+ �νe�+ �ντ CC�Anti-�νe� CC�νe� CC�ντ CC�


0

10

20

30

40

50

60

0 5 10 15 20 25 30 35 40Evisible (GeV)

dN/d

Eν (

ν µ C

C e

vent

s/1.

6GeV

per

10

kton

)

νµ + �ντ CC + background�νµ CC�ντ CC�Background�


0

20

40

60

80

100

0 5 10 15 20 25 30 35 40Evisible (GeV)

dN/d

Eν (

ν ev

ents

/1.6

GeV

per

10

kton

)

ν NC + �ντ CC�ν NC�ντ CC�

E�µ = 30 GeV, L = 7400 km, 10�21� �µ+ � decays�

0

20

40

60

80

100

120

140

160

180

0 5 10 15 20 25 30 35 40Evisible (GeV)

dN/d

Eν (

ν µ C

C e

vent

s/1.

6GeV

per

10

kton

)

νµ + �ντ CC + background�

νµ CC�

ντ CC�

Background�

Event classes

Right sign µ

Wrong sign µ

ElectronsNC-like

Combining all classes⇒ (over-constrained) sensitivity to all oscillations!


Expected sensitivity to θθθθ13 at a neutrino factory

NuFact: Eµ=30 GeV, L = 7400 km�

10-4

10-3

10-2

10-6 10-5 10-4 10-3 10-2 10-1 1sin2 2Θ13

∆m2 23

(eV

2 )

90% ALLOWED

SUPER-K ALLOWED

2 x 1020 µ(background)

2 x 1020 µ

(no background)

2 x 1021 µ(no background)

2 x 1021 µ(background)

4 years CNGS + atm

✯ Very long baseline:L=7400 km

✯ Search for wrong-signmuons

Ο Strongly depends onbackground level forwrong-sign muons

Ο Might be the only way tomeasure θ13


Conclusion

✯ The ICARUS T600, based on the novel ICARUS technique, is now almost ready.

✯ Given the past record with previous prototypes, we are confident that also the

T600 will come into operation smoothly…

➜We hope to present the first 20 m long tracks with 3 mm granularity

soon!

➜ It will demonstrate that the technique , even on such large scales, is now

mature .

✯ Then, the first T600 Module should be installed into the Gran Sasso tunnel.

✯ Operation inside tunnel in the course of next year (2002) should allow an

appropriate scaling up for the increase of the mass

✯ The technology, once it is scaled to the “right” size , will become a powerful

tool in particle physics, in particular in order to explore neutrino oscillations from

both accelerator and non-accelerator beams and proton decay.

Documents

The ICARUS Projecticarus.lngs.infn.it/serwer/conferences/Uppsala.pdf · André Rubbia, ETH/Zürich, ICARUS Collaboration, 11/2/01 Neutrino and rare process physics The performance