1

Super muon-neutrino beam

Takashi Kobayashi

IPNS, KEK

Fact02July 1, 2002Imperial CollegeLondon

Contents1. Introduction2. “Super-beam” long baseline experiments3.Physics sensitivity4.Summary

2

Next goals of LBL experiments Establish 3 flavor framework (or find something new)

Discovery of e appearance (13>0?) At the same m2 as disapp. Firm evidence of 3gen. mix. Open possibility to search for CPV

Confirmation of

Appearance NC measurement

Precision measurements of ocs. params. m23,23/m13,13

Test exotic models (decay, extra dimensions,….)

Sign of m2

Search for CPV in lepton sector Give hint on Matter/Anti-matter asymmetry in the universe

3

What’s super muon-neutrino beam?

ProtonBeam

Target FocusingDevices

Decay Pipe

Beam Dump

,K

Pure beam ( 99%)≳e ( 1%) from ≲ e chain and K decay(Ke3)

/ can be switched by flipping polarity of focusing device

““Conventional” neutrino beam productionConventional” neutrino beam production

with MW-class proton beam

For high precision LBL experiments

4

“Super beam LBL experiments”≈ “2nd generation LBL experiments

w/ high intensity conventional beam” High statistics

Beam intensity 100kW ≲ MW (super beam)≳ AND/OR detector mass ~10kt 100~1,000kt

Designed and optimized after the knowledge of Super-Kamiokande/K2K results

Primary goal: e app. CPV, sign of m2

Japan: JHF(off-axis)SK/HK FNAL: Off-axis NuMI, Proton driver upgrade, BNL: Super AGS(off-axis)? CERN: SPLFurejus, Off-axis CNGS

5

Next critical pathe appearance

SignalSignal

Single EM shower

BackgroudBackgroud

e

1. Beam intrinsic e contaminationIdentical signature w/ signalDifferent energy distribution

2. NC 0 production

3. NC multi pion production

x0

x

x

6

Key for e appearance experiment High statistics Small background contamination (beam)

intrinsic e short decay pipe,… off-axis, … less high energy tail less inelastic

Background rejection (beam+detector) event topology (e⇔0) narrow spectrum beam w/ neutrino energy reconstruction additional kinematical constraint

Small systematic error on background estimation near/far spectrum difference cross section detector response

7

High intensity narrow band beam-- Off-axis (OA) beam --

(ref.: BNL-E889 Proposal)

TargetHornsDecay Pipe

Far Det.

Decay Kinematics

Increase statistics @ osc. max.Decrease background from HE tail

1/~ E(GeV)

E(GeV)

E(

GeV

)

5

12

]mrad[

30]GeV[max

E

flux

8

Charged current cross sections

CCqe (+n+p)

InelasticNC0

multi ….

CCqe dominate 1GeV≲Inelastic dominate 1GeV≳

Backgroud

9

Background rejection Event topology

0: for example, additional EM activity? vertex displacement ( flight) angular distribution

intrinsic beam e: no way

E distribution Signal peaked at osc. max. Fake “e” event by 0&beam e broad

OA2deg@JHF

e

Typical OA spectrum

10

E reconstruction

≲1GeV 2-body kinematics

of dominant CCqe Water Ch. works well

≳1GeV Inelastics (nuclear resonances) dominate (Fine grain) sampling calorimeter. Resolution? Full reconstruction of secondary particles?

11

reconstruction ≲1GeV region

CC quasi elastic reaction

cos

22

pEm

mEmE

N

N

+ n → + p

-

p

(E, p)

+ n → + p +

-

p

(E, p)

CCqe

Inelastic (BG)

CCqe

inelastic~80MeV(10%)limited by Femi motionSmall BG

SK FullDet. Sim.

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Syst. error: far/near spectrum diff.Typical OA beam(80mDV)

280m

295km

K2K case (MC)

FD(300m)(xLSK

2/LFD2)

SK

Important not only for disappearance,but also for sig/BG estimation for e search

Large(~x2) effectaround peak!!

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(“super-beam”) LBL experiments

Ep(GeV)

Power

(MW)Beam

〈 E

〉(GeV)

L

(km)

Mdet

(kt)

CC

(/yr)

e

@peak

K2K 12 0.005 WB 1.3 250 22.5 ~50 ~1%

MINOS(LE) 120 0.41 WB 3.5 730 5.4 ~2,500 1.2%

CNGS 400 0.3 WB 18 732 ~2 ~5,000 0.8%

JHF-SK 50 0.75 OA 0.7 295 22.5 ~3,000 0.2%

JHF-HK 50 4 OA 0.7 295 1,000 ~600,000 0.2%

OA-NuMI 120 0.3 OA ~2 730? 20kt? ~1,000? 0.5%

OA-NuMI2 120 1.2 OA ~2 730? 20kt? ~4,000? 0.5%

AGS?? 28 1.3 WB/OA ~1 2,500? 1,000? ~1,000?

SPL-Furejus 2.2 4 WB 0.26 130 40(400) 650(0) 0.4%

OA-CNGS 400 0.3 OA 0.8 ~1200 1,000? ~400 0.2%The plans are in very different phases. Most are in optimization phase.JHF-SK most advanced

budget request submittedEXISITING real detector

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JHF-Kamioka Neutrino Project

~1GeV beamKamiokaJAERI

(Tokaimura)

0.77MW 50 GeV PS

( conventional beam)

Super-K: 22.5 kt

4MW 50 GeV PS

Hyper-K: 1000 kt

Phase-I (0.77MW + Super-Kamiokande)Phase-II (4MW+Hyper-K) ~ Phase-I 200

Plan to start in 2007(hep-ex/0106019)

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Principle of JHF-Kamioka project Intense Narrow Band Beam by “off-axis”. Beam energy is at the oscillation maximum.

High sensitivity, less background ~1 GeV beam for Quasi-elastic interaction.

E(reconstruct) – E (True) (MeV)

=80MeV

E(

reco

nst

ruct

)

E (True)

events

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JHF Facility

Construction2001～ 2006 (approved)

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

Super Conductingmagnet for beam line

Near detectors@280m and@~2km

1021POT(130day)≡ “1 year”

(0.77MW)

Budget Request of the beam line submitted

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Expected spectrum

e contamination

0.21%

K-decay

-decay

Very small e/

@ peak~4500 tot int/22.5kt/yr~3000 CC int/22.5kt/yr

OA3°OA2°OA1°

Osc. Prob.=sin2(1.27m2L/E)

m2=3x10-3eV2

L=295km

osc.

max

.

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Detectors at near site Muon monitors @ ~140m

Behind the beam dump Fast (spill-by-spill) monitoring of beam direction/intensity

First Front detector “Neutrino monitor” @280m Intensity/direction Neutrino interactions

Second Front Detector @ ~2km Almost same E spectrum as for SK Absolute neutrino spectrum Precise estimation of background Investigating possible sites

1.5km

295km

0.28km

Neutrino spectra at diff. dist

280m

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Far Detectors

48m × 50m ×500m,

Total mass = 1 Mton

４０ｍ

４１．４ｍ

1st Phase (2007~, ≥5yrs)Super-Kamiokande(22.5kt)

2nd Phase (201x~?)Hyper-Kamiokande(~1Mt)

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USA: FNAL and BNL plan BNL: Super AGS (1.3MW, LOI submitted) FNAL: Super NUMI (1.6 MW) or the new proton

driver.

Off-axis beams + 2 detectors

100kmFNAL BNL

Soudan

Homestake

WIPP

(hep-ex/0205040,0204037,hep-ph/0204208)

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OA-NuMIA. Para, M. Szleper, hep-ex/0110032

Osc. max. @ 730km1.8GeV (m2=3x10-3eV2)

K decay0.78deg

FeaturesNuclear resonance region Inelastic background Energy reconstruction?Too large angle Kaon peakBeam goes 3.5deg downward hard to place 2nd near det. Far/near ratio? Para/Szleper’s prescription using Matrix (hep-ex/0110001)

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Europe: SPLFurejusG

enev

e

Italy

130km

40kt400kt

CERN

SPL @ CERN2.2GeV, 50Hz, 2.3x1014p/pulse 4MWNow under R&D phase

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DetectorsUNO

(400kton Water Cherenkov)Liquid Ar TPC(~100kton)

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Physics Sensitivity

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e appearance in JHF-Kamioka (phase 1)

e0

1.8 events 9.3 events 11.1 events

123.2 events @ sin2213=0.1, m2=3×10-3eV2

Backgrounds

Signal

(5 years running)

2626

ee appearance (continue) appearance (continue)

sin22e=0.05 (sin22e 0.5sin2213)

3×10-3

×20 improvement

CHOOZ

sin22e =1/2sin2213

m2

sin2213<0.006 (90% C.L.)

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disappearance

1ring FC -like

Non-QE

(log)m2=3×10-3

sin22=1.0

~3%

m2

sin22

sin22m

2eV2

Oscillation with m2=3×10-3

sin22=1.0

Reconstructed E (MeV)

(sin22) OAB-2degree

0.01

True m2

sin22

310-3

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Sensitivity(3) to CPV(2nd phase)

Chooz excluded@m31~3x10-3eV2

>~27deg

>~14deg

Preliminary

4MW,1Mt2yr for

6.8yr for

JHF1 3 discovery

29

US Super beam• They are studying the physics potential of

several options, which are competitive to JHF-Kamioka project.

CHOOZNUMI-offaxis

|Ue3|2 =1/4sin2213 0.003

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Possibility to discriminate sign of m2 (Matter effect)

Small matter effect in JHF-SK (~1GeV-295km)

Other longer baseline projects could play complementary role

OA-NuMI MC study

m232true=+

(m2)sol=10-7eV2

sin2sol=0.25sin2atm=0.5

hep-ex/0206025

3

For example,~5yrs of OA-NuMIx20kt(w/ proton driver)

Running time:~1:3(cross sec. diff)

31

Summary Exciting topics in 2nd generation LBL experiment

s. ne appearance CPV, sign of m2, ……

Several “super-beam” experiments are under consideration US, Europe and Japan They are in very different stages.

Earliest beam is expected in 2007 at JHF-Kamioka project Accelerator construction started in 2001. Budget request for facility submitted this year.

32

Summary (II) Physics sensitivity of JHF-Kamioka project

sin213≤0.006 (90%CL) (m2) 3%, ≲ (sin223)~1% can discover CPV if 20≳ o (in 2nd phase)

Experiments are complementary each other JHF-Kamioka hard to see matter effect Longer baseline/higher energy experiments

Fact will come after the (at least) 1st round of super-beam experiments (10~20yrs) If sin213 0.01, JHF-SK may not see, but JHF-HK may.≲ But sensitivity to CPV in JHF-HK reduces CPV in Fact?

33

Future ProspectFuture Prospect

JHF1

sin2213>0.018?

JHF2CPVprecision meas. 13

Proton decay

JHF2Search 13 <10-3

Proton decay

2007

201x

2002 : JHFn budget request&approval2003 : start construction2005 : K2K final results

Future SuperBeam, VLBL, -fact for very small 13, CPV, sign of m220xx

3 discovery

Hint?

3434

(Super) Neutrino Beams(Super) Neutrino Beams<E<E>>(GeV)(GeV)

LL

(km)(km)#CC#CC

/kt/yr/kt/yrL/LL/Losciosci..** f(f(ee) @pe) @pe

akak

K2KK2K 1.31.3 250250 22 0.470.47 ~1%~1%

NuMi (High E)NuMi (High E) 1515 730730 31003100 0.120.12 0.6%0.6%

NuMi (Low E)NuMi (Low E) 3.53.5 730730 469469 0.510.51 1.2%1.2%

CNGSCNGS 17.717.7 732732 24482448 0.100.10 0.8%0.8%

JHF-IJHF-I 0.70.7 295295 133133 1.021.02 0.2%0.2%

Numi off-axisNumi off-axis 2.02.0 730730 ~80~80 0.890.89 0.5%0.5%

JHF-IIJHF-II 0.70.7 295295 691691 1.021.02 0.2%0.2%

SPLSPL 0.260.26 130130 16.316.3 1.211.21 0.4%0.4%

3535

FNAL, BNL to SoudanFNAL, BNL to Soudan

Water Cherenkov like Super-KWater Cherenkov like Super-K

Even

ts/0

.1G

eV

/5years

/10

0kTon

Even

ts/0

.1G

eV

/5years

/10

kTon

1 off-axis

x

36

3. Experiments with the super neutrino beam

37

Contents

1. Introduction2. Physics goals of next generation long baselin

e experiments3. Super-beam experiments4. Physics potential of super-beam experiments5. Comparison with Fact6. Open questions7. Summary

38

Far/near spectrum ratio

0.28km 0.5km

1.0km 1.5km 2.0km

0 1 3 5 (GeV)

2

2

)(

)(

nearnear

farfar

LE

LE

Decay pipe len.LDV=80m

want near det.@ 10≳ xLDV

3939

Sensitivity for Mixing AngleSensitivity for Mixing Anglesi

n22

e s

en

sitiv

ity

~JHF2-HK 1yr

4040

→→ confirmation w/ NC interactionconfirmation w/ NC interaction

NC 0 interaction ( + N → 　 + N + 0) e CC + NC(~0.5CC) ~0 (sin22e~0)

CC + NC(~0.5CC) ~0 (maximum oscillation) NC

#0 is sensitive to flux. Limit on s (f(s)~0.1)

s

=390±44#0 +

#e-

lik

e

m2323.510-3

CC

NC

4141

(High Intensity) Proton Accelerators(High Intensity) Proton Accelerators

Power(MW)

Energy(GeV)

Intensity(1012 ppp)

Rep. rate(Hz)

KEK-PS 0.005 12 6 0.45

AGS 0.14 24 60 0.6

FNAL-MI 0.41 120 40 0.53

SPS 0.3 400 35 0.16

JHF-I 0.77 50 330 0.29

Super-AGS 1.3 28 120 2.5

FNAL-proton driver-I

1.2 16 30 15

SPL 4 2.2 230 50

JHF-II 4 50

Not the construcion stage yet, but R&D stage.

42

Some ideas for OA-NuMI detector(under consideration)

1m

Plastic pellets +RPC (A.Para)

70ton/plane

20m

20m

SOMINOS(Fe+Sci) Szleper+Velasco

5kt, 12m dia., 875planes

43

Super Proton Linac (SPL) @ CERN

H-

RFQ RFQ1 chop. RFQ2 RFQ1 chop. RFQ2 0.52 0.7 0.8 dump

Source Low Energy section DTL Superconducting section

45 keV 3 MeV 120 MeV 2.2 GeV

40MeV 237MeV

11.5 m 55 m 584 m

PS / Isolde

Stretching andcollimation line

Accumulator Ring

Debunching

383MeV

665 m

DTL CCDTLchopping

Parameter Value Unit Mean beam power 4 MW Kinetic energy 2.2 GeV Repetiton rate 50 Hz Pulse duration 3.3 s Pulse intensity 2.27 1014 p/pulse

Under R&D phase

Reuse some parts from LEP