Road Map of Future Neutrino PhysicsA personal view

Ken PeachRound Table discussion at the 6th NuFACT Workshop

Osaka, Japan

26th July – 1st August 2004

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

Key questions1. Is the LSND effect real?

• (Desperately waiting for MiniBooNE)• If LSND effect real

• What happens to the Standard Model?• What experimental programme is required?

2. Is 13>0?• Need T2K, “child-of-CHOOZ”, …

• If 13=0 (or <<1o)• Why?• What next?

3. What is the absolute mass scale?• KATRIN, 0, cosmology/astrophysics?

• It makes a difference if mlightest = 0eV, 10-10eV, 10-1eV

4. Do neutrinos have a Majorana component?• 0

• If not, why not?• If yes

• How to measure the phases?• What is the Majorana mass mechanism?

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

Let us assume

• LSND is not confirmed

• 13>0

• 13 precisely– Need to understand the hierarchy of the angles

• Phase angle precisely– Need to look for CP/T violation– may not be large

• Determine the sign of m223

– Possibly parasitic on one of the above

• Determine the absolute mass scale– KATRIN, 0, cosmology/astrophysics

• Look for 0

… then we need to measure…

When?

Note

LSND apart

SK, SNO, KL, K2Kshow that

non-standard effects

are

smallsmall

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

Oscillations: What to Measure?

Neutrinos

e disappearance

e appearance

e appearance

disappearance

e appearance

appearance

… and the corresponding antineutrino interactions

Note: the beam requirements for these experiments are:

high intensity known flux

known spectrum known composition (preferably no background)

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

CP sensitivitydomain of 99% CL effect for maximal CP violation

Bouchez

Degeneracies – need complementary measurements

(baselines, energies, flavours, channels)

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

How to get there?

Build the Neutrino Factory as soon as

possible

Numi/CNGS,Off-Axis Beams, SuperBeams,

Beta Beam,Neutrino Factory

The Fast Train The Slow Train

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

How to choose?

The Fast Train• Advantages

– fastest route• (possibly)

– cheapest route• (possibly)

• Disadvantages– money

• (big commitment)

– politics• (related to money)

The Slow Train

• Advantages– incremental

• (duplication?)– lower risk

• (e.g. if no CPV)

• Disadvantages– costs more

• (duplication)– may never get there

• (why measure better?)

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

A Neutrino Factory is …

… an accelerator complex designed to produce >1020 muon decays per year directed at a detector thousands of km away

Principal Components

High Power H(-) sourceProton

DriverTarget Capture

Co

olin

g

Muon Acceleration

‘near’ detector (1000-3000km)

‘far’ detector (5000-8000km)

Muon

Storage

Ring

‘local’ detectors

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

Neutrino Factory Challenges

• Technology– Proton driver

• RCS or LINAC?– Proton energy?

• HARP, E910, MIPP– Target

• MW beam power– Mercury, solid, liquid-cooled, pellet, …

– Pion/muon collection and/or cooling• Magnetic Horns or Solenoids?• Phase Rotators, FFAG’s, cooling (ring, linear, …)?

– RF and acceleration• RLA’s or FFAG’s?

– Muon Storage Ring• Racetrack, triangular or bow-tie• Conventional or FFAG?

Options

2

6

3

2 x 6

2

3 x 2

5184

72

Some don’t work – divide by 2

¾ don’t make any sense

36

9

Not all match efficiently

~ 9 feasible NF designs!!!!

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

Neutrino Factory R&D

• High Power proton drivers – MW power, ns pulses

• RF – 30% of the cost?

• Cooling– How much? (20% of

the cost?)

• RLA or FFAG?– Which is cheaper?

BNL Feasibality Study 2

Ken PeachNuFact04, 26th July to 31st August 2004, Osaka, Japan

Summary

• My view

– we will need a neutrino factory

• especially if the neutrino sector is more complicated than 3 generation mixing

– there are enough technology options to be confident that it will work

• but we need demonstrators

– need to avoid (too much) duplication• (how many Megaton Water Cerenkov’s equal one

Neutrino Factory?)