Neutrino Oscillation Physics Neutrino Oscillation Physics at a Neutrino Factoryat a Neutrino Factory

Rob Edgecock RAL/CERN-ABRob Edgecock RAL/CERN-AB

OutlineOutline

• Neutrino Factory accelerator

• “ “ detector

• Reminder of phenomenology

• Atmospheric parameters

• Sign of m223

• 13 and

• Degeneracies

• Conclusions

Neutrino Factory AcceleratorNeutrino Factory Accelerator

Important parameters:Important parameters:

Muon energyMuon energy = 20 or 50 GeV Intensity= 20 or 50 GeV Intensity= 10= 102121 muon decays/year

Neutrino Factory AcceleratorNeutrino Factory Accelerator

Advantages of a Neutrino Factory:Advantages of a Neutrino Factory:

• Muon decay:Muon decay:

• Pure beam of equal numbers of Pure beam of equal numbers of and and ee

• Can look for:Can look for:

• First requires “simple” detectorFirst requires “simple” detector

• High intensity (especially High intensity (especially ee))

• Precisely known intensity and compositionPrecisely known intensity and composition

• Precisely known energy spectraPrecisely known energy spectra

ee

e

e

Neutrino Factory DetectorsNeutrino Factory Detectors

Magnetised iron calorimeter

20m long 10m radius 40kT

Events in 1 year:Events in 1 year:

1.0x1052.4x1061.2x1063500km

1.1x1055.9x1073.5x107732km

Signalsin213=0.01

Baseline CC CCe

Neutrino Factory DetectorsNeutrino Factory Detectors

For For ee or or identificationidentification

Liquid argon TPC, etcLiquid argon TPC, etc

e-id up to 5 GeVe-id up to 5 GeV

Neutrino Factory DetectorsNeutrino Factory Detectors

LANNDDLANNDD

- 70kT70kT

- 61m x 44m61m x 44m

- up to 1Tup to 1T

- 18.5MA18.5MA

- coil: 71kTcoil: 71kT

- yoke: 677kTyoke: 677kT

PhenomenologyPhenomenology

P(e) to lowest order in the matter effect:

where

To first order, ignoring matter effect and CP:To first order, ignoring matter effect and CP:

PhenomenologyPhenomenology

20 GeV 20 GeV NF at NF at

3500km3500km

PhysicsPhysics

• Precise measurement of atmospheric parametersPrecise measurement of atmospheric parameters

• Sign of Sign of mm222323

• 1313

•

• Solar parametersSolar parameters

• ee

PhysicsPhysics

From Bueno et al Nucl Phys B589 (2000) 577

Characterise as: - electrons - right-sign muons - wrong-sign muons - others

Plots are for: E = 30 GeV L = 7400 km 1020

decays 10 kT detector

Atmospheric ParametersAtmospheric Parameters

Fitting to plots, after kinematic cutsFitting to plots, after kinematic cuts

No background Perfect resoln

Background and resoln

Resolutions achieved:Resolutions achieved: 1% in1% in10% in10% in

223m

232sin

Sign of Sign of mm22

Only Only ee have CC interactions with have CC interactions with electrons in matterelectrons in matter

eeffective massffective mass

Modifies transition probability:Modifies transition probability:

EnGA eF22

E

LmP e 4

sinsin2sin2232

232

132

E

mP m

e 4

27.1sinsin2sin

2232

232

132

wherewhere

21313

213

2

132

2cos2sin

2sin2sin

xm

21313

2 2cos2sin xL

223m

Ax

Sign of Sign of mm22

Integrated

Energy bins

2x102x102020 muon decays SMA muon decays SMA parametersparameters

………….in case where one/both solar parameters small!.in case where one/both solar parameters small!

• Determined from a fit to energy spectraDetermined from a fit to energy spectra

• This time, wrong sign muons dominateThis time, wrong sign muons dominate

No background Background

90% CL90% CL

732km

3500km

7332km

• Probably the most important parameterProbably the most important parameter

•

• The good newsThe good news

23131223131213 sinsinsinsin2sin2sin2sin2

1~)()( cPP ee

• The bad news…….matter effect…….The bad news…….matter effect…….

• ………….and correlations……...and correlations……..

• ………….and degeneracies.and degeneracies

13=8o, =-90o, 0o, 90o, 180o

DegeneraciesDegeneracies

Degeneracy: 2 or more parameter sets fit the same data

Three types, all of which can effect measurement of & 13:

1313 ',',

223

223 mm

4,

2 232323

(1)

(2)

(3)

They limit the accuracy of the parameter measurement

,',' 1313 ee

PP

,',' 1313 ee

PP (1)

DegeneraciesDegeneracies

E

Lm

E

Lm

44cot2sincotcos'

,'212

213

12231313

13

large

NB depends on L/E possible solutions

• Two baselines and E-dependence at NF

• NF + SB combination

• Two off-axis detectors

• e as well as e

13=8o, =-90o, 0o, 90o, 180o

DegeneraciesDegeneracies

NuFact at 2810km + SB at 130KM

NuFact at 732km + SB at 130KM

large

small

Silver ChannelSilver Channel

Golden:Golden:

Silver:Silver:

e

e

40kT magnetised iron at 3000km40kT magnetised iron at 3000km

4kT emulsion at 732km4kT emulsion at 732km

Parameters:Parameters: = 90= 90oo

= 5= 5oo

Lines of Lines of equivalent equivalent probabilityprobability

Solve ambiguities for all Solve ambiguities for all and and 11oo

SensitivitiesSensitivities

Intermediate and long baseline best Intermediate and long baseline best Resolution: Resolution: ~0.1~0.1o o for for 1313

~20~20oo for for

ComparisonsComparisons

90% CL

JHF-HK = 4MW, 1000kT; 6 years , 2 years

NuFact-II = 5.3 x1020 useful /yr, 50kT; 4 years

ComparisonsComparisons

ConclusionsConclusions

• Neutrino Factory is the ultimate long baseline facilityNeutrino Factory is the ultimate long baseline facility

• In one year……In one year……

atmospheric parameters:atmospheric parameters:

sign of :sign of : 400400sinsin2213 13 :: 4 x 104 x 10-4 -4 at 90% CLat 90% CL ::

9090oo to <2 x 10 to <2 x 10-5 -5

• The only serious competition from combinations of othersThe only serious competition from combinations of others

• Can also do a wide range of other physics:Can also do a wide range of other physics:- short baseline, high intensity neutrino physics- short baseline, high intensity neutrino physics - -

high intensity slow muon physicshigh intensity slow muon physics - test - test bed for other projects: bed for other projects: muon collidermuon collider

proton machines proton machines

1% in 1% in 10% in10% in

223m

232sin

223m