Yury Kudenko Institute for Nuclear Research RAS

Yury KudenkoInstitute for Nuclear Research RAS

NPD RAS Session ITEP, 30 November 2007г.

Accelerator neutrino experiments: new results and

perspectives

30 November 200730 November 2007 Yury Kudenko INR RASYury Kudenko INR RAS 22

Neutrino oscillationsК2К

MINOS OPERA

MiniBooNEТ2К NOVA

LSND

e

m232, sin2223

sterile

13 CP(?)


e

U

1

2

3

Mixing matrix

atmospheric

3

2

1

1212

1212

1313

1313

2323

2323

1 0 0

0 cos sin -

0 sin cos

cos 0 sin-

0 1 0

sin 0 cos

cos sin- 0

sin cos 0

0 0 1

i

ie

e

e

solar

link between atmospheric and solar

321

321

321

UUU

UUU

UUU

Ueee

U parameterization: three mixing angles 12 13 23

CP violating phase 222jiij mmm 02

31223

212 mmm two independent m2

2231

223

2212 atmsol mmmmm

3 families


Mixing and masses

Oscillation parameters central value 2 interval m2

12 (10-5 eV2) 7.6 7.1 - 8.3 m2

31 (10-3eV2) 2.4 2.0 - 2.8 sin212 0.32 0.26 - 0.40sin223 0.50 0.34 - 0.67sin213 0.0 <0.05

3 families

Mixing Quarks Leptons1-2 12 13o 33o

2-3 23 2.3o 45o

1-3 13 0.5o <10o

CP = ?

Global data from: solar, atmospheric,reactor,LBL accelerator experiments


e [|Uei|2] [|Ui|2] [|Ui|2]

Normal Inverted

m2atm

(Mass)2

m2sol}

m2atm

m2

sol}

or

sin213

sin213

Mass spectrum


Long baseline accelerator experiments

Main goals: search for e 13

precise measurement m223 23

mass hierarchy m213 > 0 or m2

13 < 0 CP CP 13 Ue3 = sin 13exp(-iCP)

LBL experiments cannot distinguish between Dirac and Majorana neutrinosdo not provide information about absolute mass


Oscillation experiments:Appearance and Disappearance

ijji

jjiiijji

jjii UUUUUUUUP

2sin)Im(2sin)Re(4)( **2**

E

Lmijij 4

2


( x)

L/E 200

L=250 km <E> 1.3 GeV

98.2%e 1.3%

m2 210-3ev2

First LBL experiment К2К1999-2005

~1 event/2 days at SK

Predictions of flux and interactions at Far Detector by Far/Near ratio

Signal of oscillation at K2K Reduction of events Distortion of energy spectrum

disappearance


Expected: 158.1 + 9.2 – 8.6Observed: 112

- # Events

Null oscillation probability

#events 0.06% (3.4)

shape 0.42% (2.9)

Expected shape (no oscillation)

Best fit

Best fit valuessin22 = 1.00m2 [eV2] = (2.80 0.36)10-

3

Kolmogorov-Smirnov testBest fit probability = 37%

Null oscillation probability (shape + # events) = 0.0015% (4.3)

K2K final result

- Shape distortion

PRD74:072003,2006

+


Near Det: 980 tons

Far Det: 5400 tons

735 km

Beam: NuMI beam, 120 GeV Protons - beam

Detectors: ND, FD

Far Det: 5.4 kton magnetized Fe/Sci Tracker/Calorimeter at Soudan, MN (L=735 km)

Near Det: 980 ton version of FD, at FNAL (L 1 km)

Precise study of “atmospheric” neutrino oscillations, using the NUMI beam and two detectors

MINOS


1.27x1020 POT expect: 336 14.4 detect: 215

First MINOS result

k2k

Best fit valuessin22 = 1.00m2 [eV2 ] = (2.74 + 0.44 - 0.26) 10-

3

PRL 97(2006)191801


New MINOS result 2.50 POT analyzed ≈ 2x statistics of 2006 result Improved analysis

Comparison of new and old MINOS results

J.Thomas, talk at Lepton-Photon2007

# expected (no osc.) 73830# observed 563

m223 =(2.38 +0.20 -0.16) x 10-3

sin2223=1.00 -0.08


m223 and 23: SK/K2K/MINOS

|m223|| m2

13|= (2.4 0.2)x10-3 eV2 23 ~ 45o


After 5 years running: expected accuracy of m232 and sin2223 10%

chance for first indication of non-zero 13

MINOS: projected sensitivityM.Ishitsuka, talk at NNN07


OPERA

High energy, long baseline beam( E 17 GeV L ~ 730 km )

direct search

pure beam: 2% anti <1% e

P( ) = cos413sin223sin2[1.27m223L(km)/E(GeV) ]

E/L ~ 2.310-2 10m223 (atm)

Pb

Emulsion layers

1 mm

kink

after 5 years data taking:~22000 interactions~120 interactions~12 reconstructed<1 background event

Target mass ~1300t


OPERA DetectorOPERA Detector

Hybrid Detector:•Two supermodules – Target Mass 1766 tons• 2 Magnetic spectrometers with RPC & Drift tubes• 2 x [31 Target Tracker planes and Target Walls]• 206,336 “ECC bricks” (56 Pb/Emulsion layers)• 12 M Emulsion plates (thin double-coated)

beam

Two supermodules

Muon spectrometers p/p < 20% for p<50 GeV

)%3.01.0(misscharge


OPERA: OPERA: sensitivity sensitivity

full mixing, 5 years run 4.5 x1019pot/y

M.Spinetti, talk at NNN07

New MINOS


13: global

13 100

T. Schwetz, hep/ph 0606060


LSND result

m2 = 0.2 – 10 eV2 best fit: m2 = 0.2–10 eV2 sin22 = 0.003


Oscillations before first MiniBooNe result


magnetic horn: meson focusing

decay region: , K

movable absorber: stops muons, undecayed

mesons

“little muon counters:”

measure K flux in-situ

→

e?

50 m decay pipeFNAL 8 GeV Beamline

MiniBooNE detector

e e ??????

Protons from the 8 GeV booster Neutrino Beam <E>~ 1 GeV

12m sphere filled withmineral oil and 1520 PMTslocated 500m from source

MiniBooNE


MiniBooNE result 6 x1020 POT PRL 98:231801,2007 [arXiv:0704.1500]

No e excess in oscillation signal region E> 475 MeV

however


• e (LSND anti-nu)• excess at low energy

MiniBooNE result

No evidence for e appearance oscillations


Possible interpretations if low-energy excess is confirmed to be a real signal

+ N + N + + N + Coupling between , Z and

2.610-41(E/GeV)6(g/10)4 cm2

С.С.Герштейн, Ю.Я.Комаченко, М.Ю.Хлопов, ЯФ 33 (1981) 1597J.Harvey, C.Hill, R.Hill, arXiv:0708.1281[hep-ph]

3 + 2 or 3 + 3 modelsM.Maltoni, T.Schwetz, arXiv:0051.0107[hep-ph] A.Nelson, J.Walsh, arXiv:0711.1363[hep-ph]

• Non-oscillation

• Oscillation

3 +1 model ruled out M.Maltoni, T.Schwetz, arXiv:0051.0107[hep-ph]

Extra dimensionsH.Pas, S.Pakvasa, T.Weiler, hep-ph/0504096 (prediced low-energy excess)

Lorentz violationT.Katori, A.Kostelecky, R.Tayloe, hep-ph/0606154


Second generation LBL experiments

T2KNOVA

Off Axis Neutrino Beams

• Increases flux on oscillation maximum• Reduces high-energy tail and NC backgrounds• Reduces e contamination from K and decay


T2KT2K ((TTokaiokai to to KKamioka)amioka)

~1GeV beam (100 of K2K)

JPARC facility

on-axisoff-axis beam

JPARC MINOS Opera K2KE(GeV) 50 120 400 12Int(1012 ppp) 330 40 24 6 Rate (Hz) 0.29 0.53 0.17 0.45Power (MW) 0.77 0.41 0.5 0.0052

Statistics at SK OAB 2.5 deg, 1 yr = 1021 POT, 22.5 kt~ 2200 tot ~ 1600 charged current e < 0.5% at peak


OA3°

TargetHornsDecay Pipe

SuperKOA2°

OA2.5°

T2K off-axis beam

0 deg

0o


p

140m0m 280m 2 km 295 km

on-axis

off-axis

T2K setup

SK monitor

ND280mND2km

neutrino decayvolume

Possible Future T2K-II


Principle Goals of T2KPrinciple Goals of T2K

Background uncertainty 10%CP = 0 CP = /2CP = - /2 CP =

- - Search for e appearance 13 sensitivity 1o (90% c.l.)

-Measurement m223

with accuracy of 1%(sin2223) 0.01 (m2

23) < 110-4 eV2

m2=2.5x10-3


CHOOZ limit

T2K sensitivity to 13

ambiguities: CP - 13 sign m223 23


NOA

15.4m

15.4m

70m

15 ktons 15.4m x 15.4m x 70m1003 liquid scintillator planes (~80% active)Scintillator cells 3.8 x 6.0 x 1540 cm3

Read out from one side per plane with APDs

To 1 APD pixel

W D

typicalchargedparticle

path

L

To 1 APD pixel

W D

typicalchargedparticle

path

L

810 km baseline

Far Detector

Near detector Active element:Liquid scintillatorU-shaped WLS fiber


NOA

Mass hierarchy can be resolved if 13 near to present limitusing both anti- beams andsin2213 from T2K + reactor experiments

matter effects increase (decrease) oscillations for normal (inverted) hierarchy for

P( e) depends on

sin2213 sign m223 CP


13 sensitivities vs time

A.Blondel et al.,hep-ph/0606111

Short baseline reactor experiments Double-Chooz and Daya Bay 13 ( insensitive to CP)

Daya Bay goal


Conclusion K2K confirmation of atmospheric neutrino oscillations discovered by SK

MINOS confirmed the SK и K2K results high precision measurements of oscillation parameters

MiniBooNe rules out (98% cl) the LSND result as e

oscilations with m2 ~ 1 eV2 new anomaly appears run with anti- beam OPERA data taking begun in 2007

T2K-I neutrino beam in 2009

Main goal for next 5 years: 13

Yury Kudenko Institute for Nuclear Research RAS

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