long baseline neutrino oscillation...

Long Baseline Neutrino Oscillation Experiments

Alfons WeberUniversity of Oxford

XXXVIIth Recontre de Moriond

"Electroweak Interactions and Unified Theories"

Les Arcs, Savoie, France March 9-16, 2002

A. Weber LBL Experiments 2

Contents• Introduction• Long baseline experiments

– K2K– MINOS– OPERA– ICARUS– KamLAND

• The Future– SuperBeams– Neutrino Factories


Introduction• Several indication for neutrino oscillations

– Solar neutrino problem• Homestake, SAGE, GALLEX• Kamiokande, Super-Kamiokande, SNO

– Atmospheric neutrino problem• Kamiokande, IMB, Frejus, NUSEX, Soudan 2, SuperK

– LSND effect• LSND, KARMEN

• New precision experiments are needed!– replace natural with man-made neutrino source– tune oscillation distance and energy to problem


Neutrino Oscillations12 13 13 12 13 1

23 12 12 13 23 12 23 12 13 23 13 23 2

23 12 12 23 13 12 23 23 12 13 13 23 3

ei i

i i

c c c s sc s e c s s c c e s s s c s

s s e c c s c s e c s s c c

δ δµ

δ δτ

ν νν νν ν

= − − − − − −

24 2 23

13 23

1.27( ) cos ( )sin ( )sin

m LP

Eµ τν

ν ν θ θ ∆

→ =

Disappearance of atmospheric muon neutrinos:

6 parameter to be determined:•3 angle•2 mass differences•1 CP violating phase

difference mass and angle mixing ,sin ),cos(with 2ij ==== ijijijijij ?m?)(?sc θ


K2K

• Distance: 250 km• Beam Energy: 12 GeV• Neutrino Energy: 1.3 GeV


MINOS

• Beam travels 730 km toSoudan Minnesota

• FNAL Main Injector– E = 120 GeV – 4x1013 ppp (?)– Cycle 2 sec– 10 µsec spill

• Tuneable neutrino Energy– Peak at: 3, 7, 15 GeV


IHEP-Beijing lCollege de France l Athens l Dubna l ITEP-Moscow l Lebedev l ProtvinoCambridge l Oxford l Rutherford l Sussex l University College London

Argonne l Brookhaven l Caltech l Chicago l Elmhurst l Fermilab l James Madison l

Harvard l Illinois l Indiana l Livermore l Macalester l Minnesota l Northwestern l

Pittsburgh l South Carolina l Stanford l Texas-Austin lTexas A&M lTufts lWestern Washington l Wisconsin

Around 180 Physicists and Engineers

MINOS Collaboration


• 2 Super-modules 2.7 kiloton each

• 486 planes of steel and scintillator

• 96 scintillator stripseach plane

• double sided read-outwith multi-anode PMTs

• Toroidal magnetic field(1.5 T at 2 m radius)

• Very similar near detector!

MINOS Far Detector


8 m

Scintillator Module

WLS

Fib

ers

WLS

Fib

ers

Optical Connector

Optical Connector

Optical Connector

Optical Connector

Cle

ar F

iber

Rib

bon

Cab

le (2

-6 m

)

MultiplexBox

MultiplexBox

PMTs

Con

nect

ion

to

elec

troni

cs

Con

nect

ion

to

elec

troni

cs

MINOS Scintillator Module• 4-8m

scintillator modules

• 24-28 strips• double sided

readout• multi anode

PMTs (16/64)


Bottom steel plane layerTop steel plane layerScintillator plane

Orientations alternate ±90o

in successive planes

2-m wide, 0.5-inch thicksteel plates

MINOS Plane


• Several channels to analyse neutrino oscillations– T-Test = #CC / #NC–– νe appearance (θ13)–

• Combination of all analysis will reveal mixing parameters– ∆m2

– sin22θ– flavour

ντ appearance

νµ disappearance

µ? µ

hadrons

5 m

? µ

hadrons

? µ

1.5 m

MINOS Oscillation Physics


• Select ?µ charge current events and reconstruct neutrino energy

• Energy resolution:

• Compare energy spectrum in near and far detector

• Measure ? m2 and sin22?

hEEE += µν

range, B field calorimetry

EEE

pp

hh /%60/

%10/

=∆

=∆ µµ

? m2

sin22?

?µ CC Energy Analysis


?µ Disappearance Results


• CERN SPS– Ep = 400 GeV– 4.8*1013 ppp – cycle 6 - 27.6 sec– 7.6*1019 pot/year

• Baseline: 730km• <E?> = 17 GeV• optimised for t

appearance

CNGS Beam

CERN Neutrinos to Grand Sasso

• Experiments– ICARUS– OPERA

– try find t by searching for decay kink

– nuclear emulsion


29 groups~ 130 physicists

METU, Ankara, Turkey • LAPP and Université de Savoie, Annecy, France •INFN and Bari University, Bari, Italy • IHEP, Beijing, China PR • Humboldt University,Berlin, Germany • Bern University, Bern, Switzerland • INFN and

Bologna University, Bologna, Italy • IIHE (ULB-VUB), Brussels, Belgium • Joint Institute for Nuclear Research (JINR), Dubna, Russia • Laboratori Nazionali di

Frascati, INFN Frascati, Italy • Toho University, Funabashi, Japan • CERN, Geneva, Switzerland • Märkische Fachhochschule FB Elektrotechnik, Hagen,

Germany • Technion, Haifa, Israel • Hamburg University, Hamburg, Germany •High Energy Physics Group Shandong University, Jinan, Shandong, China PR •Aichi Educational University, Kariya, Japan • Kobe University, Kobe, Japan •

IPNL and Université C.Bernard, Lyon, France • INR, ITEP and MEPHI, Moscow, Russia • Münster University, Münster, Germany • Nagoya University, Nagoya, Japan • INFN and "Federico II" University, Naples, Italy • LAL and

Université Paris-Sud, Orsay, France • INFN and Padova University, Padova, Italy • INFN and "La Sapienza" University, Rome, Italy • Rostock University, Rostock, Germany • INFN and Salerno University, Salerno, Italy • IRES,

Strasbourg, France • Utsunomiya University, Utsunomiya, Japan • Rudjer Boskovic Institute (IRB), Zagreb, Croatia

OPERA Collaboration


~ 10

mν

µ spectrometerMagnetised Iron Dipoles

Drift tubes and RPCs

ν target and τ decay detectorEach “super-module” is

a sequence of 24 “modules” consisting of

- a “wall” of Pb/emulsion “bricks”- planes of orthogonal scintillator strips

scintillator strips

brick wall

module

brick(56 Pb/Em. “cells”)

8 cm (10X0)

super module

The OPERA Experiment


Emulsion-Scintillator strip Hybrid Target

•Tracker taskselect bricks efficiently

• High scanning power + low background allow coarse tracking

Selected bricks extracted dailyusing dedicated robot

Sampling by Target Tracker planes ( X,Y )

Brick wall

10 c

m

Selected brick

Event as seen by the target tracker

0 max

p.h.

OPERA Target Section


ν

Origami packed ECC brick for OPERA

Vacuum packing• Protection against light

and humidity variations.• Keep the position between

films and lead plates.• Vacuum preserved over

10 years

10X0 ( 56 emulsion films )

12.5cm235k bricks for 3 super modules

OPERA Emulsion Brick


“ Long decays″reconstruct kink topology

“ Short decays ″detect large impact parameter track

Loose cut to reject low momentum tracks

OPERA ?t Candidates


∆m2 = 1.2x10-3 eV2

at full mixing

sin2 (2θ) = 6.0x10-3

at large ∆m2

(average 90 % CL upper limit for a large number of experiment in the absence

of a signal)

5 years3 years

OPERA Sensitivity

5 years data taking


OPERA90 % CL in 5 years

OPERA: ∆m2

* assuming the observation of a number of events corresponding to those expected for the given ∆m2

(mixing constrained by SuperK)

years P3σ P4σ

3 93% 83%

5 96% 91%

Probability to observe SuperK signal

90 % CL limits * ∆m2 ( 10-3 eV2 )

1.5 3.2 5.0

Upper limit 2.1 3.8 5.6

Lower limit 0.8 2.6 4.3(U - L) / (2*True) 41 % 19 % 12 %

Nt / year 0.82 2.82 3.66


ICARUS Sensitivityatmospheric beam

Sensitivity similar to OPERA!


• Use a very intense proton beam dump to produce neutrinos = SuperBeam – Low energy (0.2-2 GeV) low ? m2

– Medium baseline (~100 km) large rate– Massive detectors (20-1000 kton) low sin22T

• Measurement program:– Improve ? m2

23, sin22T23

– Measure ?13! Totally unconstrained!– Possibility of measuring CP violating phase d!

• Sites– CERN-Modane (SPL, 130 km)– Tokaimura-Kamioka (JAERI, 295km)

SuperBeams


SuperBeams: JHF-SuperK

• Phase II– Increase beam power: 4 MW– HyperKamiokande: 1 Mton

• Possibility of measuring CP-violation, if parameters are right!

• No need for ?-factory?

• New beam from JAERI– 50 GeV, 0.77 MW– 3.3*1014 ppp / 3.3 sec

• Phase I– approved– start operation 2007

• Detector exists!


SuperBeam Physics• CP violation (phase II)• Sensitivity (phase I)

– ?µ disappearance (1 year)

212 12

13

( ) ( )

( ) ( )

sin2sin

4 sin

eeCP

ee

P PA

P P

m LE

µµ

µµ

ν

ν ν ν ν

ν ν ν ν

θ δθ

→ − →=

→ + →

∆= ⋅ ⋅

223

2 4 223

2 313

(sin 2 ) 0.01

( ) 2 10 eV

sin 2 10

m

δ θ

δ

θ

−

−

≈

≈ ×

<

Only possible,

if KamLAND

confirms LMA!


Mostly ruled out Mostly ruled out by most recent by most recent

SNO resultSNO result

KamLAND SensitivityMeasuring ?e disappearance!


Neutrino Factory• Muon storage ring: The Ultimate Neutrino Source


Neutrino Factory Physics


Summary• Present

– K2K (nice data until 2001 and later)– KamLAND (just started taking data)

• Future– MINOS (cosmics 2001, beam 2005)– OPERA (beam 2005)– ICARUS (2005, partially approved)– JHF-SuperK (2007, not yet approved)

• Science fantasy– Neutrino Factories (2010, at the earliest)

long baseline neutrino oscillation...

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