Neutrino Physics & the ISS

Neutrino Physics & the ISS

Peter Dornan

Imperial College London

16 March 2006 P Dornan - MUTAC 2006 2

Why do Neutrino Physics?

Least understood particle Beyond the Standard Model

A trivial Addition? The Window on the Fundamental Theory?

Ultimate theory must relate quarks & leptons Cannot do this without a full understanding of the

neutrino sector Cannot do this with LHC or ILC


Neutrinos are BSM

In the SM Neutrinos are massless Lepton Flavour is Conserved Neutrino & antineutrino distinguished on the

basis of helicity Neutrino Oscillation shows

Neutrinos have mass Lepton Flavour is not Conserved Helicity cannot distinguish neutrinos from

antineutrinos


A Minor Extension of the SM?

Neutrinos are Dirac Particles Right handed Neutrinos exist

With no known interactions Or very very weak ones

Lepton Flavour is not respected But overall lepton number is conserved So Distinguish Neutrino and Antineutrino on the basis of

Lepton Number - whatever it is

Masses, Mixing Parameters - and CP Violation - just yet more parameters to feed into the theory


A Window on a Higher Theory?

now we can speculate Neutrinos are Majorana States

Neutrino and anti neutrino are not distinct Right handed neutrinos exist at very high masses -

~ unification scale

Mixing angles - and probably masses – could be related to those in the quark sector

More forms of CP violation in the lepton area than the MNS phase And this will solve the matter-antimatter mystery


Why Neutrino Physics?

These are the “Elevator” Answers For the Ultimate Theory of Particles and Forces For our Understanding of the Universe

But Improving our Knowledge demands Complex

& Challenging Experimentation. The basic tool is neutrino oscillation

From Hitoshi Murayama

When you meet your favourite senator

And want a $1B

But also to explain to immigration at O’Hare why you are coming to Fermilab


Neutrino Oscillation

Neutrinos are produced - and detected - as lepton flavour - electron, muon, tau - eigenstates

Oscillations – neutrinos produced with one flavour change to another as they pass through space

In the SM lepton flavour is conserved - no oscillations

For oscillation must have two sets of eigenstates – flavour e-states and mass e-states


`atmospheric’ `solar’ `cross/reactor’

3,2,1,, itaumuonelectronU iMNS

Oscillation defined by 3 mixing angles,

phase

ijijijij sc sin,cos

Oscillation Parametrisation


Oscillation Probability

For just two state system

E

LmP ij

ij

2

22 27.1sin2sin1

Depends upon Mixing Angle, Mass Squared Difference, L/E

More Complex for a three state systemand additional complications if neutrinos pass through matter


Oscillation Signals - Disappearance

The early evidence

Super-K Atmospheric results disappearance having travelled through the earth

SSM Prediction

Gallium Chlorine

Deficits in Solar Neutrino Flux

22323 , m

21212 ,)( me


Appearance Signals - Atmospheric

Super-K - L/E Analysis

K2K First Long Baseline

SK-I + SK+II Preliminary

L/E (km/GeV)

Dat

a/p

red

icti

on

Oscillation

No oscillation

1R- spectrum

Erec (GeV)

1 2 3 4

Nu

mb

er

of

eve

nts


Appearance Signals - Solar

The SNO Result Total Neutrino Flux as Expected

Verifies Standard Solar Model

e Detected Flux Low Electron Neutrinos have oscillated to mu or tau neutrinos

SSM Prediction Neutral Currents - Detects all Neutrinos

Charged Current - Detects Electron Neutrinos


Appearance Signals - Solar

Kamland Reactor Experiment

ceReappearan then and -

- nceDisappeara e


The Third Angle, 13

Small - only an upper limit from the Chooz Reactor Experiment

Determining just how small 13 is the next pressing problem for neutrino oscillation physics


Where are we?from: Maltoni, Schwetz, Tortola, Valle (’04)

Also know m2 > m1from matter effects in the sun


How to Proceed?

What Questions remain to be answered Many!

What must we measure? Everything we can

What can we measure? Quite a lot

With the right ingenuity - and investment


Unanswered – Non Oscillation Expts

Are Neutrinos Dirac or Majorana? Neutrinoless double-beta decay

What is the Absolute Mass? Tritium Decay Spectrum Neutrinoless double-beta decay Cosmological data


Unanswered – Oscillation Expts

Is 23 maximal?

How small is 13? CP Violation in the lepton sector? Mass hierarchy?

m3 < or > m2

Is the MNS approach correct? CPT violation? The ultimate accuracy on the mixing angles and the

mass differences What accuracy is needed?

(LSND? Sterile neutrino(s)? )


Mass Hierarchy?

Normal Inverted

Require matter interactions to distinguish.

Long Baseline

Noa > T2K

Leads to degeneracies in superbeam expts.

Critical for Neutrinoless double beta decay


CP Violation

Vitally important for our understanding of nature and the universe

Arises from phases which flip sign on the change particle antiparticle In SM Non-zero phase in the CKM quark mixing matrix

Describes observed CP violating effects Does not explain the matter antimatter asymmetry

Standard MNS matrix has one phase, , (like CKM)

BUT, if neutrinos are Majorana additional phases and potential for substantial CP violation


e Appearance in a Beam - SuperBeam

e Disappearance in a e Beam - Reactor

13 and - Leptonic CP Violation

leads to CP Violation

No term


The Imminent Future

Two long base line experiments using a beam MINOS

Numi Beam from FNAL to Soudan 735 km Two Detectors – near and far – magnetized Fe-scintillator Look for disappearance 23, m2

23

e Appearance 13 (~factor 2 better than Chooz)

OPERA CNGS Beam from CERN to Gran Sasso 732 km

One Far Detector – Emulsion Look for Appearance


In 3 – 10 Years - 13

Main aim is 13 - but will also improve other parameters

Two off-axis Superbeam Experiments T2K Noa

One or more Reactor Experiments Double Chooz

and maybe Braidwood, Daya Bay, Angra dos Deis ……


Possible Reactor Experiments

Experiment Where

Baseline

(km)

Overburden (m.w.e.)

Detector size

(t) sin2(213)

Sensitivity

(90% C.L.)Near Far Near Far Near Far

Angra dos Reis Brazil 0.3 1.5 200 1700 50 500 < ~0.01

Braidwood US 0.27 1.51 450 450 65x2 65x2 <~0.01

Double Chooz France 0.2 1.05 50 300 10 10 < ~0.03

Daya Bay China 0.3 1.8-2.2

300 1100 50 100 < ~0.01

Diablo Canyon US 0.4 1.7 150 750 50 100 < ~0.01

KASKA Japan 0.4 1.8 100 500 8 8 < ~0.02

Kr2Det (Krasnoyarsk)

Russia 0.1 1.0 600 600 50 50 < ~0.03


“neardetector”

“fardetector

Reactor Measurements of 13

No Dependence on , No matter effects


600MeV Linac

3GeV PS

50G

eV P

S(0

.75M

W)

FD

Neutrino Beam Line

To SK

Long baseline neutrino oscillation experiment from Tokai to Kamioka 　（ T2K ）

J-PARC (50 GeV PS) Construction: 2001~2007 Operation: 2008~

T2K (Approved in Dec-03) Construction: 2004~2008 Experiment: 2009 ~

JAERI@Tokai-mura(60km N.E. of KEK)

(~100xK2K)

Super-K50kton

Phase 2 4MW, Mton, CPV

Phase 1 (0.75MW + SK) x disappearance

Precise m2, sin22

e appearance Finite 13 ?


T2K prediction

90%C.L. sensitivities

sin2213

　

CHOOZexcluded

Off axis 2.5deg, 40GeV 5yr

x 20m2(e

V2)

(m223) < 1×10-4 eV2

(sin2223) ~ 0.01

For 5yr running


Noa

Upgrade of FNAL NuMi program.

Off-axis configuration, and larger proton intensity (6.5x1020 proton/year).

Very Long Baseline (810km) and sizeable matter effects

Complementary to T2K program (mass hierarchy).

<En> ~ 2.22GeV 30Kton “fully” active detector. Liquid scintillator.


Noa

Sensitivity similar to T2K.– improve with antineutrinorun.

● Sensitivity to masshierarchy.

● Synergies with T2K &reactor experiments:different matter effects anddifferent degeneracies.


The Precision Era - after T2K and Nova

Around 2012 - 2015 We shall have good measurements of

12, 23, m212, m2

23

Probably have a measurement of 13

Possibly know the mass hierarchy

So can now plan for the ultimate neutrino measurements Refine all parameters Check consistency Measure CP Violation

This is the aim of the ISS


CP Violation


Neutrino source – options:

Second generation super-beam CERN, FNAL, BNL,

J-PARC II

Beta-beam

Neutrino Factory


The International Scoping Study

International scoping study of a future Neutrino Factory and super-beam facility

Motivation

Organisation Status

Physics Group Accelerator Group Detector Group

ISS: next steps


ISS: motivation

Neutrino Factory – prior to launch of ISS Several studies at the turn of the century

US Studies I, II, IIa ECFA/CERN Study NuFact-J Study

established feasibility & R&D programme MUCOOL, MICE, MERIT….

But there have been advances since then Also appreciation of the need for an integrated

accelerator-detector-physics approach and an international approach


ISS: motivation

Goal: timely completion of conceptual design Significant international effort taking several years

Requires successful bids to provide the resources

Preparation for design study Review physics case

Critical comparison of options Review options for accelerator complex:

Prepare concept-development and hardware-R&D roadmaps for design-study phase

Review options for neutrino-detection systems Emphasis: identify concept-development and hardware-R&D

roadmaps for design-study phase Establish the Cost Drivers & Optimize

Physics/$ - where there are alternatives Absolute scientific value - where only one method


ISS: organisation


Meetings

Plenary meetings to date: CERN: 22 – 24 September 2005

Attendance: 92 Americas: 15 Asia: 12 Europe 65

KEK: 23 – 26 January 2006 Attendance: 67 Americas: 11 Asia: 28 Europe 28

Working groups: Physics:

Workshops: Imperial: 14 – 21 November 2005 Boston 6 – 10 March 2006 Phone meetings

Accelerator: Workshops: BNL: 07 – 12 December 2005 Phone meetings

Detector: Phone meetings Detector/Physics parallel at Physics workshops


Acknowledgments

This will be a very brief review of the activity in the ISS

From the meetings - very many people have contributed so - it is hard to acknowledge everyone - so I apologise for failing to mention many of the contributors

All plots and contributors can be found on the web


Physics Group

Theory subgroup : What is the new physics Need to distinguish between alternative theories Establish the case for high-precision, high-sensitivity neutrino-

oscillation programme Phenomenological subgroup

Review models of neutrino oscillations Identify measurables that distinguish them and assess the

precision required Experimental subgroup:

Use realistic assumptions on the performance of accelerator and detector to: Evaluate performance of the super-beam, beta-beam and Neutrino

Factory alone or in combination Make meaningful comparisons

Muon physics subgroup: Lepton-flavour violating processes – clear synergy with neutrino

oscillations – possibly the next major discovery


Some Theoretical Ideas

Flavour symmetry:

Quarks and charged leptons do not carry the same hidden quantum numbers

All neutrinos carry the same hidden quantum numbers Allows differences in mass hierarchies and mixing matrices to

be explained through symmetry breaking Random sampling of many such models indicates that large

θ13 is favoured


Some Theoretical Ideas

Quark-lepton complementarity

Intriguing Relations Coincidence fundamental

GUTs motivate relationships between the quark and lepton mixing matrices

Measurable relations Need Precision

41212 CKMMNS

42323 CKMMNS


A Possible Neutrino Sum Rule

cos26.35 1312

%10313

%10313

20

5.012


Towards a performance comparison

A Major Goal of the ISS Now many options Must be reduced if there is to be a realistic design for

a ‘precision era’ neutrino facility Requires justifiable assumptions:

Accelerator: flux, energy spectrum Detector: Ethresh, ERes (background, x-sect.

uncertainty…)

and optimised facility (accelerator, baseline, & detectors)

Already a very substantial amount of work


Cases under Consideration

Off axis super-beam: T2HK taken as example

Plan to explore different options (essentially vary E and L)

Beta beam: Low : = 100 and L = 130 km

High flux (~1018 decays per year) and high flux (1019 dpy) High : = 350 and L = 700 km

High flux (~1018 decays per year) and high flux (1019 dpy) Also Beta beam abd superbeam combination

Neutrino Factory Performance studied as a function of:

E and L Ethresh and ERes


Sample - CP sensitivity v. sin2213

Work in progress

But highlights the importance of 13 in defining a strategy

Huber, Lindner, Rolinec, Winter


CPT & the MNS Theory

In the Quark sector the CP violation parameters are determined in many ways

Can we do the same in the neutrino sector?

With 3 flavours and CPT CP violation related in

e ->

->

e ->

Needs tau modes

Murayama


Beta beam, super beam comparison

High θ13: Beta beam & super beam alone:

sensitivity good Poor sign(m23

2) sensitivity

T2HK

Low-E βB

High-E βB

2 MW

4 MW

Low Flux

High Flux

Low Flux

High Flux

T2HK

Low-E βB

High-E βB

2 MW

4 MW

Low Flux

High Flux

Low Flux

High Flux

Preliminary! Need to include bettertreatment ofbackgroundand sys. err.

Couce


Neutrino Factory: optimisation

Study performance as a function of muon energy and baseline

Detector: 100 kton, magnetised iron Importance of threshold

sensitivity

Can trade muon energy against detector threshold and resolution


ISS status: Accelerator Group

Subsystems & subgroups Proton driver Target and capture Front end

Bunching and phase rotation

Cooling

Acceleration Decay ring

Decay Channel

Linear Cooler

Buncher

1-4 MWProtonSource

Hg-Jet Target

Pre-Accelerator

Acceleration

DecayRing ~

1 km5-10 GeV

10-20GeV

1.5-5 GeV

Decay Channel

Linear Cooler

Buncher

1-4 MWProtonSource

Hg-Jet Target

Pre-Accelerator

Acceleration

DecayRing ~

1 km5-10 GeV

10-20GeV

1.5-5 GeV


Accelerator Group – mission

Two phase approach: Phase 1:

Study alternative configurations; arrive at baseline specifications

Develop tools required for end-to-end simulations ‘Top-down’ cost evaluation required to guide choices

Phase 2: Focus on selected option(s)

Begin to consider engineering issues Through initial engineering studies, identify R&D required in

‘International Design Study’ phase

Presently working through Phase 1 Highlights


Proton driver:

Key issues for Neutrino Factory proton driver: Beam current limitations Creation of short bunches Repetition rate limitations Space charge limitations Tolerances

Largely driven by downstream constraints

Survey carried out:

1. SPL 3.5 GeV 50 Hz 4 MW2. JPARC 50 GeV 0.33 Hz 0.6 -> 4 MW3. AGS 24 GeV 0.5 Hz 0.2 -> 4 MW4. FNAL SCL 8 GeV 10 Hz 0.5 -> 2 MW5. RAL RCS 5 GeV 50 Hz 4 MW6. RAL RCS 15 GeV 25 Hz 4 MW7. RAL FFAG 10 GeV 50 Hz 4 MW8. KEK/Kyoto 3 GeV 1 kHz 1 MW9. A. Ruggiero FFAG 12 GeV 100 Hz 18 MW10. A. Ruggiero FFAG 1 GeV 1 kHz 10 MW


RAL 4 MW FFAG Proton Driver

•RAL design

•5 bunches per pulse

•50 Hz repetition rate

•10 GeV

•Isochronous FFAG with insertions

• RF system naturally gives 2 ns rms pulse• need to add 6th harmonic to get 1 ns rms

Issue:

Bunch length at injection


Target and capture

Issues for target and capture system: Optimum proton-driver energy Optimum target material Constraints on target operation at 4 MW

Proton bunch intensity Proton bunch length Repetition rate

Possible materials Liquid mercury preferred for high-power operation Solid tantalum may be an option Carbon probably OK up to 1 MW


Target and capture: proton energy

Different simulations disagree MARS Geant4

Preliminary conclusion: Proton driver energy

in range 5 – 15 GeV

120G

eV10

0GeV

75G

eV50G

eV

40G

eV

30G

eV

20G

eV

15G

eV

10G

eV

4GeV

2.2G

eV

3GeV

5GeV

6GeV

8GeV

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

1 10 100 1000

Proton Energy (GeV)

Pio

ns

per

Pro

ton

.GeV

(es

t. P

has

e R

ota

tor)

pi+/(p.GeV)

pi-/(p.GeV)

pi+/(p.GeV)

pi-/(p.GeV)


Target and capture

MERIT experiment at CERN High-power liquid-mercury jet

target engineering demonstration


Front-end

Review and compare performance of existing schemes (CERN, KEK, US) Conclusions will require cost model to be developed

Evaluate trade-offs between degree of cooling and downstream acceptance Figure of merit (muons per proton) Need to define options for acceptance downstream of cooling

channel Small, medium, and large?

Optimisations: Minimise RF required Optimum choice of materials for absorber in cooling channel

Evaluate cost optimum


Front end: new configurations

• “Guggenheim” cooling channel• provides longitudinal cooling• solves problems with

injection, absorber heating• can taper parameters

(A. Klier)

(D. Neuffer)

• cool while doing phase rotation• cost savings• 150 atm hydrogen (room temp)• 24 MV/m RF• performance looks promising


Cooling: hardware R&D programme

Complementary programmes: MuCool:

Design, prototype, and test – using an intense proton beam – cooling channel components

MICE: Design, construct, commission,

and operate – in a muon beam – a section of cooling channel and measure its performance in a variety of modes

Both programmes well advanced


Acceleration: FFAG development Increasing effort on

scaling and non-scaling FFAG

PRISM: Phase rotated intense muon source

Under construction in OsakaCommissioning 2007

Proof of principle ‘non-scaling’ FFAGDecay ring

EMMA :Electron model of muon acceleration


Decay ring

Issues: Racetrack or triangle geometry

20 GeV or 50 GeV or 20 GeV-upgradable

How to handle both muon charges (1 ring or 2)

Length of µ bunch train (constrains circumference)

RF to maintain bunch structure

Beam loading (~MW µ beams)

Shielding from µ decays


Decay Ring - Options

Isosceles Triangle (G Rees) Circumference = 1170 m length of each production straight = 301 m (2 x 0.26 efficiency) 5 bunch trains per cycle angles of triangle depend on ring and target sites

designed for apex angle = 22.4o 27, 34.5, 45, 52 also possible (±1o)

Racetrack geometry (C Johnstone), C = 1371 m both 20 GeV and 50 GeV use same lattice production straight

496 m long (36% production efficiency) quad focusing - maximum beta = 155 m, 167 m


ISS status: Detector Group

Detector options and subgroups Large water Cherenkov

ISS activity focuses on consideration of R&D required: Photo tubes Front-end electronics

Liquid argon Emulsion Magnetic sampling calorimeter Near detector

Further instrumentation issues: Flux, muon-polarisation measurement


Detector technology: summary

Magnetised liquid argon: Golden, platinum, and silver channels accessible

Magnetised sampling calorimeter: Golden channel accessible

Sampling fraction: Can totally active ‘get’ some silver or platinum sensitivity

Hybrid detector system?


Liquid argon

Detector concepts

Various configurations being studied in ISS: Glacier T2K-LAr (near det.) NuMI LArTPC


Emulsion detector – MECC

Stainless steel or Lead Film Rohacell

DONUT/ OPERA type target + Emulsion spectrometer + TT + Electron/pi discriminator

B

Assumption: accuracy of fi lm by fi lm alignment = 10 micron (conservative)

13 lead plates (~2.5 X0) + 4 spacers (2 cm gap) (NB in the future we plan to study stainless steel as well. May be it will be the baseline solution: lighter target)

The geometry of the MECC is being optimized

3 cm Electronic detectors/ ECCStainless steel or Lead Film Rohacell

DONUT/ OPERA type target + Emulsion spectrometer + TT + Electron/pi discriminator

BB

Assumption: accuracy of fi lm by fi lm alignment = 10 micron (conservative)

13 lead plates (~2.5 X0) + 4 spacers (2 cm gap) (NB in the future we plan to study stainless steel as well. May be it will be the baseline solution: lighter target)

The geometry of the MECC is being optimized

3 cm Electronic detectors/ ECC


Magnetic sampling calorimeter

Concept: Magnetised iron?

Sampling fraction?

Air toroid Cost

~ $300M

Basic Detector Concept

7.5 mm

15.0 mm

Considered Extremely Fined Grained

Electro

n

Mu

on


Near detector

Measurement of cross sections in DIS, QE and RES.

Coherent Different nuclear targets: H2, D2

Nuclear effects, nuclear shadowing, reinteractions

With modest size targets can obtain very large statistics

What is lowest energy we can achieve? E.g. with LAr can go down to ~MeV

Measurement of cross sections in DIS, QE and RES.

Coherent Different nuclear targets: H2, D2

Nuclear effects, nuclear shadowing, reinteractions

With modest size targets can obtain very large statistics

What is lowest energy we can achieve? E.g. with LAr can go down to ~MeV


Timescales: the challenge


ISS – Summary The ISS was launched at NuFact05 and is now half way

through its one year programme Conclude at NuFact06 and a report early fall

It has demonstrated a strong desire to have an internationally coordinated effort for future neutrino research (c.f linear collider) New ideas Many clarifications

It has brought together accelerator & detector scientists with their experimental and theoretical physics colleagues in a very productive way

It has built up a momentum which must be used as a springboard for the next phase


ISS – Immediate Future

Next Plenary Meeting RAL, UK, April 24 – 29 Preceded by an Accelerator Group Workshop

Final Meeting Irvine, Aug 21 – 22 Just before NuFact06

Still much to be done – more help always welcome

Visit the website http://www.hep.ph.ic.ac.uk/iss/ Transparencies from all the meetings etc. Join the mailing lists Help to establish the best way forward

Neutrino Physics & the ISS

Documents

Transcript of Neutrino Physics & the ISS