Non-accelerator-based neutrino experiments

Yifang Wang

Institute of High Energy Physics

Beijing, 100039

Recent results on • Neutrino oscillations

– Atmospheric neutrinos: m223 and sin2223

– Solar neutrinos: m212 and sin2212

– 13 and CP phase: sin2213 and

• Neutrino masses– Absolute neutrino masses– Neutrinoless decays

• Neutrino magnetic moments

Neutrino oscillations:

Pontecorvo-Maki-Nakagawa-Sakata Matrix

Majorana phasesOnly appear in 0 decays

cij=cosij, sij=sinij

Atmospheric SolarCP phase

Mass eigenstates

Weak eigenstates

Sub-dominant 13 oscillations

A total of 6 parameters: 2 m2, 3 angles, 1 phases

+ 2 Majorana phases

Evidence of Neutrino Oscillations

Unconfirmed:LSND:m2 ~ 0.1-10 eV2

Confirmed:Atmospheric:m2 ~ 210-3 eV2

Solar:m2 ~ 8 10-5 eV2

Psin22sin2(1.27m2L/E)2 flavor oscillation in vacuum:

Atmospheric neutrinos --- SuperKamiokande

L ~ 20 km

L ~ 104 km

Earth

E ~ 300 MeV - 2 GeV

Super-K

p, He

e

P(l l )1 sin2 (2 )sin2 m 2L

4E

Oscillation probability:SK-I: 1996-2001

SK-II:2003-2005

e/ 1/2

e

e

Full analysis of SK-I ---- Zenith angle distributions

~15km ~13000km ~500km

2-flavor oscillations

Null oscillation Best fit

Saji’s talk

sin22=1.0, m2=2.1x10-3 eV2

2 = 175.2/177 dof

90% C.L. region:

sin22> 0.92,

1.5 < m2 < 3.4x10-3 eV2

L/E Oscillation result

m2=2.4x10-3,sin22=1.00

2min=37.9/40 d.o.f

(sin22=1.02, 2min=37.7/40 d.o.f)

1.9x10-3 < m2 < 3.0x10-3 eV2

0.90 < sin22 @ 90% C.L.

Strong constraint on m2

standard zenith angleanalysis(90%C.L.)

Best fit expectation

w/ systematic errors

Mostly upwardMostly downward

3-Flavor Analysis result

no

rmal

inve

rted

Bestfit: m2 = 2.7x10-

3ev2, sin223 = 0.5, sin213 = 0.0

no evidence for non zero 13

m3

m2

m1

m3

m2

m1

sin223

sin

2 1

3

m2

sin213

m2

sin

2 1

3

(preliminary)

Standard Solar model: BP04

pp (1010 cm-2 s -1)

pep (108 cm-2 s -1)

hep (103 cm-2 s -1)

7Be (109 cm-2 s -1)

8B (106 cm-2 s -1)13N (108 cm-2 s -1)15O (108 cm-2 s -1)17F (106 cm-2 s –1)

5.94 (1%)

1.40 (2%)

7.88 (16%)

4.86 (12%)

5.82 (23%)

5.71 (36%)

5.03 (41%)

5.91 (44%)

Cl SNU

Ga SNU

10-36 atom-1 s –1

8.5 1.8

131 11

Bahcall, Pinsonneault, PRL2004

Solar neutrino experiments ----- Super-K, SNO, KamLAND

Z

mantle

core

SK Day

z

SK: Un-bined day/night analysis of SKIEnergy and zenith angle dependence of event rate variatoin.

(Δm2 = 6.3×10-5 eV2, tan2θ = 0.55)

L e iBi S

i 1

N bin

1

ni

Bi U i c mi S p c , E z c , E

#B.G. in eachenergy bin

#SignalEvents

Event“Time"

BackgroundShape

Solar signalshape

ADN 0.018 0.016 0.0120.013

cf. old method 0.02 0.021 0.0120.013

j j

i

MC

MC

Ishihara’s talk

Average of SK-I

Period '96-'01 accident '03-'05#PMTs 11,146 5,182Photo Coverage 40 % 19 %Light yield ~6 p.e./MeV ~2.8 p.e/MeV Energy threshold 5.0 MeV 8.0 MeV

SKII works well

The Sudbury Neutrino Observatory

• 2092 meters deep underground• 1000 tons of ultrapure D2O in a 12 meter diameter acrylic vessel

• 7000 tons of ultrapure H2O as shield • 9500 PMTs • 40 helium proportional counters with total length of 398 m

CC:e + d e- + p + p

NCx + d x + n + p

ESx + e- x + e-

e

x= e+

x= e+()/6

Three neutron detection methods

energy

Isotropyradius

direction

Signal extraction in salt phaseDeng’s talk

Neutrino flux: > 0

)sys()stat(21.2Φ 10.010.0-

+0.310.26-ES

+=

)sys()stat(76.1Φ 09.009.0-

+0.060.05-CC

+=

)sys()stat(39.2Φ 12.012.0-

+0.240.23-ES

+=

)sys()stat(09.5Φ 46.043.0-

+0.440.43-NC

+=

)sys()stat(59.1Φ 06.008.0-

+0.080.07-CC

+=

)sys()stat(21.5Φ 38.038.0-

+0.270.27-NC

+=

D2O phase salt phase(unit 106/cm2/s)

SSM8

meas8 )(0.23(th))exp)(04.088.0()( BB

First salt results

KamLAND

Sources: reactor neutrinos

• 200 MeV/fission

• 6 e/fission

6 1020 e/s/3GWth

Flux and spectrum of reactor neutrino are known within 3%

Null Oscillation Probability

Disappearance 99.995%Shape Distortion 99.9%Combined 99.99996%

Hypothesis test

Scaled no oscillation

excluded at 99.9% C.L.

Shimizu’s talkShimizu’s talk

Combined solar Combined solar νν – KamLAND 2-flavor analysis – KamLAND 2-flavor analysis

Includes (small) matter effectsIncludes (small) matter effects

07.009.040.0tan

105.06.02.8

122

25212

eVm

A new background just found:

preliminary

13C(, n)16O ~ 10 event

Accidental 2.69 ± 0.028He/9Li 4.8 ± 0.9 induced n < 0.89

Previously estimated backgrounds

An incomplete list of “exotic” explanations• Atmospheric neutrinos (m2

23)– Atmospheric neutrino production model:

K2K– e, s

– CHOOZ, SK Fit, Tau appearance

– Decoherence: SK, KamLAND

– neutrino decays: SK, KamLAND

• Solar neutrinos (m212)

– Standard Solar Neutrino(SSN) model– Solar density profile– SNO( appearance), KamLAND

– SMA, QVO-VO, LOW solutions: KamLAND– Spin-Flip, non-standard interactions, …

– KamLAND

– Decoherence: SK, KamLAND

– neutrino decays: SK, KamLAND

Neutrino oscillations established

SuperK KamLAND

Decay* excluded at 95% CL

Decoherence† excluded at 94% CL

*V.Barger et al. Phys. Rev. Lett. 82 (1999) 2640

†E.Lisi et al., Phys. Rev. Lett. 85 (2000) 1166

A total of six mixing parameters ：Known ： | m2

32|, sin2232 --Super-K

m221, sin2221 --SNO,KamLAND

Unknown ： sin22 ， , sign of m232

at reactors:

Pee 1 sin22sin2 (1.27m2L/E)

cos4sin22sin2 (1.27m2L/E)

at LBL accelerators:

Pe ≈ sin2sin22sin2(1.27m2L/E) +

cos2sin22sin2(1.27m212L/E)

A()cos213sinsin()

Why at reactors• Clean signal, no cross talk with and matter

effects• Relatively cheap compare to accelerator based

experiments • Can be very quick• Provides the direction to the future of neutrino physics

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

0.1 1 10 100

Nos

c/Nn

o_os

c

Baseline (km)

Small-amplitude

oscillation due to 13

Large-amplitude

oscillation due to 12

Current Knowledge of 13

Maltoni etal., hep-ph/0405172

Sin2(213) < 0.09

Sin2(213) < 0.18

At m231 = 2103 eV2,

sin22 < 0.15

K.B.Luk’s talk

How to reach 1% precision ?• Three main types of errors: reactor

related(~2-3%), background related (~1-2%) and detector related(~1-2%)• far/near detector to cancel reactor errors• movable detectors, near far ?• optimum baseline • detector design threshold, fiducial volume, resolution, scintillator,

light transport, … • sufficient shielding • calibration• statistics

Typical precision: 3-6%

xperi

Proposed Reactor Neutrino Experiments

Angra, Brazil

Diablo Canyon, USA

Braidwood, USAChooz, France Krasnoyasrk, Russia

Kashiwazaki, Japan

Daya Bay, China

Currently Proposed sites/experiments

Site

(proposal)

Power

(GW)

Baseline

Near/Far (m)

Detector

Near/Far(t)

Overburden

Near/Far (MWE)

Sensitivity

(90%CL)

Angra dos Reis (Brazil)

4.1 300/1300 50/500 200/1700 0.007

Braidwood (US) 6.5 270/1800 25/50 450/450 0.01

Chooz-II (France) 8.4 150/1050 10/10 60/300 0.03

Daya Bay (China) 11.6 350/1800 20/40 250/1200 0.01

Diablo Canyon (US)

6.4 400/1800 25/50 100/700 0.01

Kashiwazaki (Japan)

24.3 350/1300 8.5/8.5 300/300 0.02

Krasnoyarsk (Russia)

3.2 115/1000 46/46 600/600 0.01

Sensitivities to Sin2213 @ 90%CL

Double Chooz

KASKA

BraidwoodDaya Bay

PowerBaselineDetectorOverburden

rock

watermodule with 10

t Gd-doped liquid scintillator

Two veto detectors: Water + RPC multiple detector modules for

Redundancy is important to achieve <1% precision

Daya Bay experiment

Absolute neutrino masses

• β-decay:

(m ve)eff =[Σi | Uei |2 m2 vi

]1/2

• Endpoint of decays

3H → 3He + e- + e

E0 = 18.574 KeV

• Currently the best limit:

m< 2.2 eV @ 95%CL

• Katrin expected: m

< 0.3 eV @ 95%CL

Neutrino mass from

Cosmology

Data mi

@95%CL)*References

2dFGRS < 1.8 eV Elgaroy et al. PRL 89, 2002

WMAP+2dF+… < 0.7 eV Spergel et al. APJS 148,2003

WMAP+2dF < 1.0 eV Hannestad, JCPA 0305, 2003

XLF+WMAP+2dF+…

0.56+0.30 -0.26 eV Allen et al. MNRAS346(2003)

SDSS+WMAP < 1.7 eV Tegmark et al. PRD 69,2004

WMAP+ACBAR+

2dF+SDSS+…

< 1.0 eV Crotty et al. PRD 69,2004

*With different assumptions, fitting constrains and datasets

A strong constraint to LSND and Heidelberg-Moscow decay results

Continuous spectrum Monochromatic spectrum

decays : <Mee> = | Σi (Uei )2 m vi

|

Resolution and backgrounds are critical

NEMO-03 first results

Ec1+Ec2 (keV)

DataMonte-CarloRadonMonte-CarloT1/2 = 3.5 1023

100Mo 6914 g

216.4 days4.10 kg.y

Ec1+Ec2 (keV)

100Mo: T1/2() > 3.5 1023 y (@90% C.L.) m < 0.7 – 1.2 eV82Se: T1/2() > 1.9 1023 y (@90% C.L.) m < 1.3 – 3.6 eV

3 m

4 mB (25 G)

20 sectorsLalanne’s talk

100Mo 6.914 kg

Q= 3034 keV

82Se 0.932 kg

Q= 2995 keV

Current 0 resultsNucleus Detector (kg yr) Present T1/2

0 (yr) <m> (eV)

48Ca >9.5*1021 (76%CL)76Ge† Ge diode ~30 >1.9*1025 (90%CL) < 0.39+0.17

-0.28

82Se Foils 0.5 >1.9*1023 (90%CL) <1.3-3.6100Mo foils 4.1 >3.5*1023 (90%CL) <0.7-1.2116Cd >7.0*1022 (90%CL)128Te TeO2

cryo~3 >1.1*1023 (90%CL)

130Te TeO2 cryo

~3 >2.1*1023 (90%CL) < 1.1 - 2.6

136Xe Xe TPC ~10 >1.2*1024 (90%CL) < 2.9150Nd >1.2*1021 (90%CL)160Gd >1.3*1021 (90%CL)

† Controversial claim of positive 0signal with m = .39 eV c.f. Klapdor-Kleingrothaus Mod. Phys Lett. A27 (2001) 2409

EXO – a novel technology to remove backgrounds

• 136Xe 136Ba++ + 2e-

identified using optical spectroscopy

2P1/2

4D3/2

2S1/2

493nm

650nm

metastable 47s

30%

8 ns

850 m

Hz/bin

• Ions observed in .01 torr xenon

• Indefinite gas lifetime

• Trap dynamics dominate

• to be demonstrated in liquid or high

pressure gas environment

SNR ~100:1

S.Waldman’s talk

200 kg prototype underway

Strategy of the XMASS project

Dedicated detector forDouble beta decay search

~1 ton detector(FV 100kg)Dark matter search

~20 ton detector(FV 10ton)Solar neutrinosDark matter search

Prototype detector (FV 3kg) R&D

~2.5m~1m~30cm

NOW

Confirmation of feasibilities of the ~1 ton detectorAnalysis techniquesSelf shielding performanceLow background propertiesPurification techniques

Takeuchi’s talk

Future -decay experiments

Isotopes enrichment Mass

(t)

Sensitivity

(eV) (90%CL)

CUORE 130Te no 0.75 ~ 0.03

GENIUS 76Ge yes 0.1-1.0 ~ 0.01

Majorara 76Ge yes 0.42 ~ 0.02

MOON 100Mo yes 3.0 ~ 0.01

Super-NEMO 82Se yes 0.1 ~ 0.03

EXO 136Xe yes 10.0 ~ 0.01

A few of them will be realized

Direct searches of Neutrino magnetic moments

Finite mass Finite (e), SM: ~ 10-19 B

Enhanced by new physics

Signature: 1/T excess due to

-e scattering via channel

Sources: Kuo-Sheng reactor in Taiwan

Detector: 1Kg HPGe

No excess for ON/OFF

Limit:

e) < 1.3 10-10 B (90% CL)

Texono, Jin Li’s talk

22

11)(2

ETmedT

de

Current experimental limitsExperiments Up Limits @ 90% CL References

Texono e ) < 1.3 10-10 B PRL 90, 2003

MUNU e ) < 1.0 10-10 B PLB564, 2003

SK+all data + KamLAND ) < 1.1 10-10 B PRL93, 2004

Borexino ) <5.5 10-10 B PLB 563,2003

LSND e ) < 1.1 10-9 B

) < 6.8 10-10 B

PRD 63, 2001

DONUT ) < 3.9 10-7 B PLB 513, 2001

Future experimentsExperiments Sensitivity @ 90% CL Status

GEMMA e ) 3 10-11 B 2004

MAMONT e ) 2 10-12B R&D

Texono(ULEGe) e ) 2 10-11B R&D

Summary• Neutrino oscillations established

– Solar: m212 = (8.2+0.6

-0.5)10-3 eV2

tan212 = 0.40 +0.09-0.07 large but not maximal

– Atmospheric: m223 = (2.40.4)10-3 eV2

sin2223 > 0.92 @ 90%CL maximal – From global fit: sin2213 < 0.09 @ 90%CL

• Our next goal:– Absolute neutrino masses -decay experiments

– Dirac or majorana ? 0-decay experiments

– 13, CP and Mass hierarchy Reactor, Long baseline accelerator based experiments

A great success in the past A long way to go in the future