This is what we want to know...

Value of 13

Value of

m2

?

m2

?

c

130 s

13e i

0 1 0

−s13

ei 0 c13

Normal or inverted?

UMNSP

=0.8 0.5

0.4 0.6 0.70.4 0.6 0.7⇔U

CKM=

0.975 0.222 0.0040.221 0.97 0.04

0.01 0.04 0.999Better estimates of theoscillation parametersusing accelerators

Majorana?

Is the atmospheric mixingangle maximal?

   

The fly in the ointmentThe LSND experiment was the first accelerator experimentto report a positive appearance signal

E : 20-55 MeVbaseline : 30mL/E 1.0

1280 PMTs167 t liquid scintillator

++

e+

e

↳

e

ep e+ n

20-60 MeV

n p d

2.2 MeV

   

LSND Result87.9 ± 22.4 ± 6 excess events

m2 = 1.2 eV2

3.3 evidence for oscillations

   

LSND Result87.9 ± 22.4 ± 6 excess events

m122~8×10−5eV 2

m23

2~2.5×10−3eV 2

m??2~1eV 2

m12

2 m

23

2 m

31

2=0

fourth neutrino?

   

Karmen II • Pulsed 800 MeV pot (ISIS)

– DAR beam (90º to target)– 17.6 m baseline

• 56 tons of liquid scintillator– 512 modules– Gd-doped (8 MeV γ )

factor of 10 less statistics than LSND (less intensity & size)

11 events observed12.3 events expected

   

MiniBooNECurrently running since 2002 at Fermilab

Average neutrino energy ≈ 1 GeV

L/E the same as LSND

Same technology as LSND

Different energy = different event types = different systematics

Looks for →

e oscillations =

e →

if CPT

symmetry holds

   

Blind analysesNo excess of

e events in

signal region (E>450 MeV)Unknown excess of events

at low energy

   

New analysis, withbetter backgroundtreatment

excess still there forneutrinos at 3

but not for antineutrinorunning!

NB LSND ran with antineutrinos too - no sign ofan LSND-like excess either

   

Lecture 5

To the Future...and beyond!

To the Future...and Beyond!

   

The next 20 years

Measurement Method Experiments Why? When

MINOS More precise 2007

Estimates

T2K, NovA Is it maximal? 2009

T2K, NovA Equal to 0? Can't 2012

Reactor 2012

Disapp.

T2KK, neutrino Unification, GUT 2025?

Factory, ??? Lepton asymmetry

|m23

2| Disapp.

23

Disapp.

13

e Appear.

measure CP

if it is

Anti-e

Sgn(m23

2) e / anti-

e

CP

   

MINOS

Near Detector980 ton @ 1km

Far Detector5.4 kton @ 730 km

Det. 2

Det. 1

31 m long iron scintillator calorimeter5.4 kton Iron targetFirst magnetized

underground detector

   

NuMI Beam

0.4 MW proton beam

   

MINOS

m2 = 0.0024 eV2

sin2(2) = 1.0

m232~7 %

Error on sin2(2)is dependent on number of protonsdelivered by machine

m2=2.43±0.13×10−3 eV 2

sin220.9

   

→

?

Main aim is to provide evidence of →

oscillations

in the atmospheric sector by looking for appearance

   

OPERA

   

OPERA Signal

   

How OPERA works

Rencontres de Moriond EW 2008 C.Pistillo - Bern Univ. 7

ν  

Target Tracker + Brick Walls

Spectrometer

µ

0 max

p.h.

On-line analysis of electronic data

Brick finding algorithm

Selected brick is removed from the target and exposed to cosmic rays (alignment). Emulsions are developed and sent to scanning stations / labs

   

Automated emulsion analysis

Bern emulsion scanning lab.

Predictions from electronic detectors are followed back inside the brick until tracks stop. Then a full scanning around neutrino interaction vertex is performed and the event topology and kinematics reconstructed.

Emulsion scanning is performed in a fully automatic way. About 40 microscopes are operational in the various OPERA scanning laboratories.

ν µ CC interaction

h

muon

2 cm

2

mm

   

   

13,

Mass heirarchy, CP

ViolationTo determine the rest of the parameters, we will lookat the

→

e oscillation in the atmospheric sector

13=0 Pe=sin2 212 sin2m12

2 L

4 E

13≠0

Pe=cos213sin2 212sin2 m12

2 L

4 E sin2

23 sin2 213sin2m 232 L

4 E Jcos ±−

m232 L

4 Em12

2 L

4 Esin m23

2 L

4 E

Solar

Solar

Atmos.

Interference

   

Measuring 13

P

e

   

Measuring 13

13=0o

13=9o

   

How do we get to 13

?

P

e=sin2 2

13sin2

23

sin21.27m

232 L

E

e oscillations with atmospheric L/E

Pe

x=sin22

13sin21.27m

232 L

E

e

x disappearance oscillations with atmospheric L/E

e

x disappearance oscillations with atmospheric L/E

Pe

x=

C PP

e

x

   

How do we get to 13

?

P

e=sin2 2

13sin2

23

sin21.27m

232 L

E

e oscillations with atmospheric L/E

Pe

x=sin22

13sin21.27m

232 L

E

e

x disappearance oscillations with atmospheric L/E

e

x disappearance oscillations with atmospheric L/E

Pe

x=

C PP

e

x

   

Reactor Experiments

Pe

e=1−sin2

213sin2

m

232 L

4 E−cos4

13sin2

212sin2

m

122 L

4 E

   

   

4 high power reactorsMultiple detectors with

cross calibrationGood shielding from

muons and neutrons Results around 2011

sin22

13~0.01

   

How do we get to 13

?

P

e=sin2 2

13sin2

23

sin21.27m

232 L

E

e oscillations with atmospheric L/E

Pe

x=sin22

13sin21.27m

232 L

E

e

x disappearance oscillations with atmospheric L/E

e

x disappearance oscillations with atmospheric L/E

Pe

x=

C PP

e

x

   

The Challenge

Need to measure small oscillation probabilities atthe atmospheric m2

This implies

Very Intense beams

Very large detectors

Very pure beams

SuperBeams

Beta beams

Neutrino Factory

2009

2012

2020

   13

determines the next 15-30 years or so of the field

   

SuperBeams

   

Supersize Me

   

Engineering Challenges

Proton Driver

High power, very short intense proton bunches

Target

Thermal management

Target melting/vaporisation

Thermal shock

Radiation

Activation of surrounding material

Remote Handling

Pion capturing and magnetic focussing

   

Targets

   

Next GenerationT2K NOvA

Site

Beam

<E>

Distance

Far Det mass

Tokai,Japan

Under Const.

0.7 GeV

295 km

Super-K22.5 kton

USA

NuMI

2.2 GeV

812 km

to be built30.0 kton

Long enough from matter effects

   

#The T2K (Tokai-2-Kamioka)

Experiment

295km

   

JPARC Beamline

Will be the most intense proton beam ever built 99%

Phase 1 : 0.75 MWPhase 2 : 4 MWNUMI – 0.4 MW

   

Off-Axis?ProtonBeam

Target Decay pipe,K

--

,K++

Magnetic Focusing

Note ability to tune the spectrum!

E=

0.43 E

12

2

FarNear

   

T2K-I Physics Goals

disappearance : P(

) = 1 – sin22

23sin2(1.27m2

23L/E)

MINOS T2K-1

0.08 0.01(sin2(223

))

(m223

) 2*10-4 eV2 1*10-4 eV2

   

   

T2K-I Physics Goals

   

NOA

   

NOA Reach

   

Indications of non-zero 13

?

Global analysis of all neutrino oscillation data

sin213=0.016±0.010

13≈8o ? 130 at 2

Chooz Bound ⇒ 1310 deg

Fogli et al, hep-ph/0806.2649

N.B. hep-ph/0403278 predicts : sin213=

23

m122

m232 ≈ 0.017

Authors : P. Harrison, W. Scott (just sayin')

   

How do we get to 13

?

P

e=sin2 2

13sin2

23

sin21.27m

232 L

E

e oscillations with atmospheric L/E

Pe

x=sin22

13sin21.27m

232 L

E

e

x disappearance oscillations with atmospheric L/E

e

x disappearance oscillations with atmospheric L/E

Pe

x=

C PP

e

x

   

In all it's naked gloryPe e=P1P2P3P4

13

23

>45 or 23

<45

Sign(m23

2)

P1=sin223sin2 21313

B -+

2

sin2B+-

2L

P2=cos223sin2 21212

A 2

sin2A2L

P3= J cos cos23

2L

12

A

13

B-+

sin A2Lsin

B-+

2L

P4=±J sin sin 23

2L

12

A

13

B -+

sinA2Lsin

B-+

2L

ij=mij

2

2 E

A=2GF N e

B -+=∣13∓A∣J=cos13 sin212 sin 223sin 213

   

Degeneracies Experiments only measure at most two numbers; but probability has three unknowns and parameters with errors.

Need more thanone measurementat different L/E todisentangle the parameter space

   

Intrinsic Degeneracies

P e

Pe e=X+­ sin2 213Y +­c cos∓Y +­

s sinsin 2 13Z

One experiment at one L/E ; only

   

Intrinsic DegeneraciesPe e=X+­ sin2 213Y +­

c cos∓Y +­s sinsin 2 13Z

One experiment at one L/E ; and

   

Intrinsic Degeneracies

2 experiments at different L/E ; and

   

Discrete DegeneraciesTwo other sources of degeneracy :

sgnm232 sgn tan 2 23

These have values of +/- 1 :

In total 23 = 8 degenerate solutions - Eightfold Degeneracy

Need lots of statistics to minimise error ellipses,and probably combinationsof machines and experiments.

   

Neutrino Factory

   

DetectorsTo see CP violation effects, the detectors have to be puta long way from the beam....roughly 3000-7000 km. Biasis at 3000 km (too small, backgrounds kill you, too large,no statistics) and 7000 km (“magic baseline”)

   

Oscillation Signatures

­e­

e

Major signal is a “wrong sign lepton”

Far detector has to be large andmagnetised

Background is charmproduction and chargemisidentification

   

They are far far away

3000 km40 kton iron

   

Physics Reach

   

Physics reach

Matter effects can be used for a long baseline

   

Mass Hierarchy - another way

m ee=∣∑iU e i

2 mi∣

Neutrinoless double beta decay

Need about 1 tonof isotope to reachthis sensitivity

   

Non-oscillation PhysicsAt a 50 GeV -Factory there could be 106-107 events/kg/yr

Precise cross section measurements

Structure function/parton distributions

QCD physics

Nuclear effects

Charm physics

Electroweak tests

Beyond-Standard-Model searches

With the right sort of near detectors (big liquid Argon?)

   

Beta beamAnother great (and less expensive) idea

The beta decay spectrum is well understood, sowhy not use that to produce a neutrino beam?

Accelerate beta-unstableions and let them decayin a storage ring pointedat a detector

Single flavour beamPrecisely known spectrumKnown intensityFocussedOnly

e though

Need very large detector butno magnetic field

   

In the meantimeCan we use the current beams to do useful physics beforethe Neutrino Factories/-beams switch on?

   

Hyper-Kamiokande

   13

determines the next 15-30 years or so of the field

   

General Comments

Neutrino Physics is one of the most active fields in modern-day particle physics

Establishment of the neutrino mass has opened up fields of study in particle physics, astrophysics and cosmology and has led to an international research effort planned on the timescale of decades.

We have learnt a bit of what is going on

We have a lot more to learn

Neutrinos have always been the joker in the deck. Just when you think you understand them, they do something unexpected. Expect more surprises

   

JPARC Schedule

Baseline

Likely

Beam development on schedule

   

How to do an oscillation experiment

Challenge : Understanding the event sampleat the far detector in the absence of oscillations

Composition of initial fluxExtrapolation of flux from near to far detectorsSignal cross sectionsBackground cross sections

   

The ProblemsNeed to know what to expect in the SK

Oscillating muon neutrino fluxelectron neutrinos in beambackground from NC events

The Solutions

Beam only on the oscillation peakMake a narrow band beam

Use near detectors to measure cross sections and neutrino flux

   

Hadronic Models

Hadronic Production experiments : SPY, HARP, MIPP

   

Cross sections

Signal () Background(

e)

   

Cross-section experiments

SciBooNE

MINERA

   

Off Axis - ND280

170k / ton / yr

3.3k e / ton / yr

ND280 Detector

   

General Comments

Neutrino Physics is one of the most active fields in modern-day particle physics

Establishment of the neutrino mass has opened up fields of study in particle physics, astrophysics and cosmology and has led to an international research effort planned on the timescale of decades.

We have learnt a bit of what is going on

We have a lot more to learn

Neutrinos have always been the joker in the deck. Just when you think you understand them, they do something unexpected. Expect more surprises