Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding...

38
Steve Elliott, SUNY 2002 Outline What is β β β β and why study it? Assumes you heard previous talks. General Experimental Issues The New Proposals Neutrinoless Double-Beta Decay Experiments Steve Elliott - Los Alamos Nat. Lab. “Neutrinos and Implications for Physics Beyond the Standard Model” SUNY Stony Brook, Oct. 10-13, 2002

Transcript of Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding...

Page 1: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Outline What is ββββββββ and why study it?

Assumes you heard previous talks. General Experimental Issues The New Proposals

Neutrinoless Double-BetaDecay Experiments

Steve Elliott - Los Alamos Nat. Lab.“Neutrinos and Implications for Physics

Beyond the Standard Model”SUNY Stony Brook, Oct. 10-13, 2002

Page 2: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

ββββββββ(2νννν) vs. ββββββββ(0νννν)

ββββββββ(2νννν): Allowed and observed 2nd order weak process.

ββββββββ(0νννν): requires massive Majorana neutrinos even inpresence of alternative mechanisms.

νννν

νννννννν

e

e

e

e

n

n n

np

p

p

p

Page 3: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

ββββββββ Decay Rates

Γ2 2 22

ν ν ν= G M Γ0 0 02 2

ν ν ν ν= G M m

G are calculable phase space factors.G0νννν ~ Q5

|M| are nuclear physics matrix elements.Hard to calculate.Present estimate of uncertainty is not well founded.

mνννν is where the interesting physics lies.

Page 4: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Neutrino Masses

Direct mass and ββββββββ experiments set absolute mass scale.

<mββββ> < 3 eV

The results of oscillation experiments set the relativemass scale.

Sets mνννν scale > 50 meV

ββββββββ also addresses Dirac/Majorana nature of νννν.

Page 5: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

3 Complementary ExperimentalTechniques

AbsoluteMassScale

RelativeMassScale

MixingMatrix

Elements

CPnature

of ννννββββββββ

ββββ

Oscil.

Need all three types of experiments to fully understand the nature of the νννν.

Page 6: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

What about mixing, mνννν & ββββββββ(0νννν)?

m U mei ii

iββ ε= ∑=

2

1

3

Compare to ββββ decay result: real νννν emission

m U mei ii

β = ∑=

2 2

1

3

virtual νννν exchangeεεεε ==== ±1, CP cons.

No mixing: m m meββ ν= = 1

Page 7: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

An exciting time for ββββββββ!

< mββββββββ > in the range of10 - 50 meV is very interesting.

For the next experiments:

For at least

one neutrino: m m meVi atmos>> ≈≈δδ 2 50

m meVββββ ≤≤ 50

Page 8: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Classes of Background

ββββββββ(2νννν) tailNeed good energy resolution.

Natural U, Th in source and shieldingPure materials, identify ββββββββ daughter, pulse shape,timing, position.

Cosmic ray activationStore and prepare materials underground.

Page 9: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

An Ideal ExperimentMaximize Rate/Minimize Background

Large Mass (~ 1 ton)Good source radiopurity

Demonstrated technologyNatural isotope

Small volume, source = detectorGood energy resolution

Ease of operationLarge Q value, fast ββββββββ(0νννν)

Slow ββββββββ(2νννν) rate

Identify daughter Event reconstruction

Nuclear theory

mb EMtlive

ββ ∝

∆14

Page 10: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

ββββββββ(2νννν) as a Background.Sum Energy Cut Only

next generationexperimentalgoal

10-4

10-3

10-2

10-1

100

101

102

103

<mββββ ββββ

> Se

nsiti

vity

(meV

)

54321Resolution (%)

100Mo

136Xe

76Ge

130Te

SB

mQe=

71 22

1 20

τδ

ν

ν/

/

2.0

1.5

1.0

0.5

0.0

dN

/d(K

e/Q

)

1.00.80.60.40.20.0Ke/Q

30

20

10

0

x10

-6

1.101.000.90Ke/Q

Page 11: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Natural Activity

The Problem:ττττ(U, Th) ~ 109 years

Target: ττττ(ββββββββ(0νννν) ~ 1027 years

DetectorShielding

Cryostat, or other experimental supportFront End Electronics

etc.

Page 12: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Cosmic Ray Induced Activity

Material dependent.

Need for depth to avoid activation.

Need for storage to allow activation to decay.

Page 13: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

A Great Number of Proposed Experiments

10 t of liquid XeXe-136XMASS

1.56 t of Xe in liq. Scint.Xe-136Xe

Mo sheets between plastic scint., or liq. scint.Mo-100MOON

500 kg Ge diodesGe-76Majorana

2 t Gd2SiO5:Ce crystal scint. in liquid scint.Gd-160GSO

1 ton Ge diodes in liquid nitrogenGe-76GENIUS

1 ton Ge diodes in liquid nitrogenGe-76GEM

1 ton Xe TPC (gas or liquid)Xe-136EXO

750 kg TeO2 bolometersTe-130CUORE

Several tons CaF2 crystals in liquid scint.Ca-48CANDLES

1 t CdWO4 crystalsCd-114CAMEO

10 kg of ββββββββ isotopes (7 kg of Mo)Mo-100, VariousNEMO

20 kg Nd layers between tracking chambersNd-150DCBA

10 kg CdTe semiconductorsTe-130COBRA

Page 14: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Present Experimental Limits

Half Life <mee>

Ge (IGEX)NP of RAS 63, 1299 (2000)

160 x 1023 y ~330 meV

Ge (Heid-Mosc)Dark Matter 2000

190 x 1023 y ~300 meV

Mo (ELEGANTS)NP A611, 85 (1996)

0.52 x 1023 y ~6600 meV

Te-130 (Cuoricino)PL B486, 13 (2000)

1.44 x 1023 y ~1700 meV

Te-128 (Geochem)PR C47, 806 (1993)

6.9 x 1024 y ~1100 meV

Xe (Gotthard)PL B 434, 407 (1998)

4.4 x 1023 y ~2500 meV

mM Gee ∝

1

0 1 2ντ /

Page 15: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

The Controversy.

Locations of claimed peaks

20

15

10

5

0

Co

un

ts

20802060204020202000Energy (keV)

16

14

12

10

8

6

4

2

0

Co

un

ts

20802060204020202000Energy (keV)

If one had to summarize the controversy in a short statement:Consider two extreme background models:

1. Entirely flat in 2000-2080 keV region.2. Many peaks in larger region, only ββββββββ peak in small region.

These 2 extremes give very different significances for peak at 2039 keV.KDHK chose Model 2 but did not consider a systematic uncertaintyassociated with that choice.

Mod. Phys. Lett. A16, 2409 (2001)

Page 16: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

“Found” Peaks:These experiments are hard

PR

D45

, 254

8 (1

992)

A 2527-keV Ge-det. peak that was an electronic artifact.

A ~2528-keV Te-det.peak that was a 2σσσσStatisticalflucuation.

NP

B35

(P

roc.

Sup

p.),

366

(19

94).

Need more thanone experiment

Page 17: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Potential Large-Mass FutureExperiments

Experiments in Europe/JapanCUORE, GENIUS, XMASS

NUSL CandidatesEXO, MAJORANA, MOON

Smaller Mass Experiments Cobra, DCBA, NEMO,CAMEO, CANDLES, GSO

Page 18: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Molybdenum Observatory OfNeutrinos - MOON

U. of WashingtonU. of North CarolinaU. of WisconsinResearch Center for Nuclear Physics,OsakaPlus others as collaboration is forming.

SpokespersonHiro Ejiri

RCNP

Page 19: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

MOON Overview

3.3 tons 100Mo, 34 tons Mo

Doesn’t require enriched material (butwould want it).

Scintillator/source sandwichPosition and single Eββββ data play big role

in ββββββββ(2νννν) and U, Th rejection.

14% efficiency

ELEGANTS is precursor.

Page 20: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

MOONScintillator

A liquid scintillator optionis also being considered.

Page 21: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Cryogenic Underground Observatory for Rare Events - CUORE

BerkeleyFirenzeGran SassoInsubria (COMO)LeidenMilanoNeuchatelU. of South CarolinaZaragoza

SpokespersonEttore Fiorini

Milano

Page 22: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

CUORE Overview

0.21 ton, 34% natural abund. 130TeTeO2 bolometers, 750 g crystals

Doesn’t require enriched material.1020 5x5x5 cm3 crystals

17 towers of 15 modules of 4 crystals

Gran Sasso LaboratoryCUORICINO begins operating this fall (45 kg).

Page 23: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

CUORE Detector

Detector Damping Suspension

Dilution Unit

ThermalShields

Page 24: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Enriched Xenon Observatory -EXO

U. of Alabama

Caltech

IBM AlmadenITEP Moscow

U. of Neuchatel

INFN Padova

SLAC

Stanford U.U. of Torino

U. of Trieste

WIPP Carlsbad

SpokespersonGiorgio Gratta

Stanford

Page 25: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

EXO Overview

10 ton, ~70% enriched 136Xe

70% effic., ~10 atm gas TPC or LXe chamberOptical identification of Ba ion.

Drift ion in gas to laser pathor extract on cold probe to trap.

TPC performance similar to that at Gottard.100-kg enrXe prototype (no Ba ID)

Isotope in hand

Page 26: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Stanford Optics Lab with Ba Trap

Ba Trap

136Xe -> 136Ba++ e-e - -> 136Ba+

Optically observe finalstate. (Moe, PRC44 (1991) 931

Page 27: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

EXO Single Ion Observation

Page 28: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Two Ge Detector BackgroundPhilosophies

ββββββββ

ββββ+

ββββββββ

Internal Background External Background

<Use pulse shape &segmentation to eliminatebackground.

>Minimize thematerials near the

crystal

Page 29: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Ge expts.: Different Approaches

If no signal seen:

If background, B~MT (i.e. within Gemass), then:

Leads to emphasis onenrichmentbalanced mass and timebackground rejection

If no signal seen:

If background, B~MT (i.e. within Gemass), then:

Leads to emphasis onenrichmentbalanced mass and timebackground rejection

If we assume background is instructural materials only, B=bTthen:

Leads to emphasis onminimized structureincreased natural mass

decreased time

If we assume background is instructural materials only, B=bTthen:

Leads to emphasis onminimized structureincreased natural mass

decreased time

21

21

1

Tm

C

MTT e =⇔= νSuppressing constants:

B

MTT >21

MTT >21b

TMT >21

“Majorana Approach” “GENIUS Approach”

Page 30: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

GErmanium NItrogen Underground Setup- GENIUS

MPI, HeidelbergKurchatov Inst., MoscowInst. Of Radiophysical Research, Nishnij Novgorod

Braunschweig und Technische Universität,BraunschweigU. of L'Aquila, Italy

Int. Center for Theor. Physics, TriesteJINR, DubnaNortheastern U., Boston

U. of Maryland, USAUniversity of Valencia, SpainTexas A & M U.

SpokespersonHans Klapdor-Kleingrothaus

MPI

GENIUS

Page 31: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

GENIUS Overview

1 ton, ~86% enriched 76Ge

Naked Ge crystals in LNVery little material near Ge.

1.4x106 liters LN40 kg test facility is approved.

100% efficient

Heid.-Moscow experiment is precursorGENIUS

Page 32: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

GENIUS Layout

GENIUS

DataAcquisition

Clean Room

LiquidNitrogen

Insulation

SteelVessel

12 m

Setup for operation ofthree 'naked’Germanium detectorsin liquid nitrogen.

Page 33: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

The Majorana ProjectDuke U.North Carolina State U.TUNL

Argonne Nat. Lab.JINR, DubnaITEP, Moscow

New Mexico State U.Pacific Northwest Nat. Lab.U. of Washington

LANLU. of South CarolinaBrown

Univ. of ChicagoRCNP, Osaka Univ.Univ. of Tenn.

Co-SpokespersonsFrank Avignone

Harry Miley

Page 34: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Majorana Overview

0.5 ton of 86% enriched 76Ge

Segmented detectors using pulse shapediscrimination to improve background

rejection.Prototypes being assembled. (18 crystals

array, 1 enriched segmented detector)

100% efficientCan do excited state decay.

IGEX is precursor

Page 35: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Majorana Layout

Page 36: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Recent Majorana pictures

Page 37: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Summary of ProposalsProposed ton-year= M * T * εεεε

Anticipated<mee>, (QRPA)

CUORE 0.21*5*1 = 1 60 meV

EXO 6.5*10*0.7 = 45 13 meV

GENIUS 1*2*1 = 2 20 meV

MAJORANA 0.5*10*1 = 5 25 meV

MOON 3.3*3*0.14 = 1.4 30 meV

The <mββββββββ> limits depend on background assumptions and matrix elements whichvary from proposal to proposal.

Page 38: Elliott Yang Inst., Oct 02insti.physics.sunysb.edu/ITP/conf/neutrino/talks/elliott.pdfShielding Cryostat, or other experimental support Front End Electronics etc. Steve Elliott, SUNY

Steve Elliott, SUNY 2002

Conclusions

Research and Development are needed for all thefuture proposed detectors.

UG Lab space will be needed for some of thatR&D.

The next generation ββββββββ experiments have agood possibility of reaching an interesting

<mββββββββ> region.