decay:Present and Future

Ruben SaakyanUCL

8 November 2004Manchester University

Particle Physics seminar

PREVIEW Motivation Present status

Status of “evidence” Future projects UK in NEMO/SuperNEMO

Motivation

e

Ue1 Ue2 Ue3

U1 U2 U3

U1 U2 U3

1

2

3

U 0.5 0.87 0

0.61 0.35 0.71

0.61 0.35 0.71

Neutrino Mixing Observed !

From KamLAND, solar and atmospheric

VERY approximately

m2LMA ≈ 5×10-5 eV2 = (7 meV)2

m2atm ≈ 2.5×10-3 eV2 = (50 meV)2

Neutrino MASSWhat do we want to know?

or

• Relative mass scale (-osc)

• Mass hierarchy (-osc and )

• Absolute mass scale ()

Dirac or Majorana

1 3e

Ue12 Ue2

2 Ue32

MixingOnly from From -osc

<m> ~ 0 - 0.01 eV <m> ~ 0.02 - 0.06 eV

preferred bytheorists(see-saw)

degenerate: <m> > 0.1 eV

Decay Basics

2+

0+

0+

0+

2-

Ge76

As76

Se76

In many even-even nuclei, decay is energetically forbidden. This leaves

as the allowed decay mode.

Q Endpoint

Energy

Double beta decay and neutrino mass

1 22 2 21/ 2 0(0 0 ) ( , )T G E Z M

1 20 0 0 21/ 2 0(0 0 ) ( , )T G E Z M m

L=0

L=2 !

Q

Effective Majorana Mass(inverted hierarchy case)

2 222 2 i

N N

ei i ei ii i

m U m U e m

Ue12 m1

Ue22 m2

Ue32 m3

<mee>

min

Isotopes

Best candidates: 76Ge, Q2.038 MeV 48Ca, Q 4.272 MeV 82Se, Q 2.995 MeV 100Mo, Q 3.034 MeV 116Cd, Q 2.804 MeV 130Te, Q 2. 528 MeV 136Xe, Q 2.48 MeV 150Nd, Q 3.368 MeV

High Q is important (G0 ~ Q5, G2 ~ Q

11) In most cases enrichment is a must Different isotopes must be investigated due to

uncertainties in NME calculations !

The Experimental Problem( Maximize Rate/Minimize Background)

Natural Activity:

(238U, 232Th) ~ 1010 yearsTarget: (0) > 1025 years

DetectorShielding

Cryostat, or other experimental supportFront End Electronics

etc.+

Cosmic ray induced activity

A History Plot

<m> < 0.35 – 0.9 eV

mscale ~ 0.05 eV from oscillation experiments

Hieldeberg-Moscow (Gran Sasso)(Spokesperson: E. Klapdor-Kleingrothaus, MPI)

<m> = 0.4 eV ???

• 5 HPGe 11 kg, 86% 76Ge• E/E 0.2%• >10 yr of data taking

<m> < 0.3 – 0.7 eV If combine HM and IGEX

First claim (end 2001)

Heidelberg claim. Recent developments

hep-ph/0403018, NIMA, Phys. Rev…Data analysed for 1990 – 2003

71.7 kgyr

• Data reanalyzed with improved binning/summing • Peak visible• Effect reclaimed with 4.2• <m> = (0.2 – 0.6) eV, 0.4 eV best fit<m> = (0.1 – 0.9) eV (due to NME)

• Looks more like 2.5 of effect•214Bi line intensities do not match

214Bi214Bi

unkn

own

Personal view

CUORICINO (bolometer)

NEMO-3(Tracking calorimeter)

These two will be determining fate until ~2007-2008Sensitivity ~ 0.2 eV

Current Experiments

Located in LNGS, Hall A

Cuoricino (Hall A)

CUORE R&D (Hall C)

CUORE (Hall A)

Today:CUORICINO

Incident particle

absorber crystal

heat bath

Thermal sensor

Today: CUORICINO

2 modules, 9 detector each,crystal dimension 3x3x6 cm3

crystal mass 330 g

9 x 2 x 0.33 = 5.94 kg of TeO2

11 modules, 4 detector each,crystal dimension 5x5x5 cm3

crystal mass 790 g4 x 11 x 0.79 = 34.76 kg of

TeO2

40.7kg total

Today:CUORICINO

• Operation started early 2003• BG = 0.19 counts/kev/kg/y• E/E = 4 eV @ 2 MeV

Neutrino 2004:m < 0.3 – 1.6 eV (all NME)

AUGUST 2001

Today: NEMO-III

100Mo 6.914 kg Q= 3034 keV

decay isotopes in NEMO-3 detector

82Se 0.932 kg Q= 2995 keV

116Cd 405 g Q= 2805 keV

96Zr 9.4 g Q= 3350 keV

150Nd 37.0 g Q= 3367 keV

Cu 621 g

48Ca 7.0 g Q= 4272 keV

natTe 491 g

130Te 454 g Q= 2529 keV

measurement

External bkg measurement

search (All the enriched isotopes produced in Russia)

Drift distance

100Mo foil100Mo foil

Transverse view Longitudinal view

Run Number: 2040Event Number: 9732Date: 2003-03-20

Geiger plasmalongitudinalpropagation

Scintillator + PMT

Deposited energy: E1+E2= 2088 keVInternal hypothesis: (t)mes –(t)theo = 0.22 nsCommon vertex: (vertex) = 2.1 mm

Vertexemission

(vertex)// = 5.7 mm

Vertexemission

Transverse view Longitudinal view

Run Number: 2040Event Number: 9732Date: 2003-03-20

Criteria to select events:• 2 tracks with charge < 0• 2 PMT, each > 200 keV• PMT-Track association • Common vertex

• Internal hypothesis (external event rejection)• No other isolated PMT ( rejection)• No delayed track (214Bi rejection)

events selection in NEMO-3

Typical 2 event observed from 100Mo

Trigger: 1 PMT > 150 keV

3 Geiger hits (2 neighbour layers + 1)

Trigger rate = 7 Hz events: 1 event every 1.5 minutes

(Data 14 Feb. 2003 – 22 Mar. 2004)

T1/2 = 7.72 0.02 (stat) 0.54 (syst) 1018 y

100Mo 22 preliminary results

4.57 kg.y

Cos()

Angular Distribution

Background subtracted

22 Monte Carlo

• Data

145 245 events6914 g

241.5 daysS/B = 45.8

NEMO-3

100Mo

E1 + E2 (keV)

Sum Energy Spectrum

145 245 events6914 g

241.5 daysS/B = 45.8

NEMO-3

100Mo

• Data

Background subtracted

22 Monte Carlo

Simkovic, J. Phys. G, 27, 2233, 2001

Single electron spectrum different between SSD and HSD

100Mo 22 Single Energy Distribution

22 HSDMonte Carlo HSD

higher levels Background subtracted

• Data22 SSD Monte Carlo

Background subtracted

• Data

SSDSingle State

HSD: T1/2 = 8.61 0.02 (stat) 0.60 (syst) 1018 y

SSD: T1/2 = 7.72 0.02 (stat) 0.54 (syst) 1018 y

100Mo 22 single energy distribution in favour of Single State Dominant (SSD) decay

4.57 kg.yE1 + E2 > 2 MeV

4.57 kg.yE1 + E2 > 2 MeV

HSD, higher levels contribute to the decay

SSD, 1 level dominates in the decay (Abad et al., 1984, Ann. Fis. A 80, 9)

100Mo

0

100Tc

1

/ndf = 139. / 36 /ndf = 40.7 / 36

NEMO-3 NEMO-3

Esingle (keV) Esingle (keV)

Esingle (keV)

Today:NEMO-III

Present 90%CL limits from NEMO-III(216.4 days) 82Se:T1/2() > 1.9 1023 y, m < 1.3 – 3.6 eV

Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001) Caurier et al., Phys. Rev. Lett. 77 1954 (1996)

100Mo T1/2() > 3.5 1023 y, m < 0.7 – 1.2 eV Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001)

Expected Reach in 5 years after RadonPurification 100Mo T1/2() > 4.0 1024 y, m < 0.2 – 0.35 eV 82Se:T1/2() > 8.0 1023 y,,m < 0.65 – 1.8 eV

Strategy for future.An Ideal Experiment

Large Mass (0.1t) Good source radiopurity

Demonstrated technology Natural isotope

Small volume, source = detector Tracking capabilities

Good energy resolution or/and Particle ID Ease of operation

Large Q value, fast (0) Slow (2) rate Identify daughter

Event reconstruction Nuclear theory

01

04

1

BGMt

m

BGMt

Ebm

live

live

All requirements can NOT be satisfied Red – must be satisfied

A Great Number of Proposals(Some may start taking data in 2009-2010)

DCBA Nd-150 20 kg Nd layers between tracking chambers

SuperNEMO Se-82, Various 100 kg of Se-82(or other) foil

COBRA

CAMEO

Te-130,Cd-116

Cd-116

CdTe semiconductors

1 t CdWO4 crystals

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

CUORE Te-130 750 kg TeO2 bolometers

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

GEM Ge-76 1 ton Ge diodes in liquid nitrogen

GERDA Ge-76 0.5-1 ton Ge diodes in LN2/LAr

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

Majorana Ge-76 500 kg Ge diodes

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

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

XMASS Xe-136 10 t of liquid Xe

GERDA. 76Ge

Phase I: collect 76Ge detectors from HM(11kg)+IGEX(8kg) 15kgy+BG@0.01 c/keV/kg/y

sens-ty: 3·1025 y, 0.24-0.77 eV Confirm Klapdor with 5 OR rule out at 98%

Phase II:enlarge to ~35-40 kg BG < 10-3 c/keV/kg/y within 4 yr ~ 100 kgy 2·1026 y, 0.09-0.29 eV 

Phase III: 0.5 -1 ton Possible merge with Majorana ~ 0.03 eV

“Naked” 76Ge detectors in LN2/LArOriginal idea from GENIUS (Klapdor)

Cryogenic Underground Observatory for Rare Events - CUORE

Berkeley

Firenze

Gran Sasso

Insubria (COMO)

Leiden

Milano

Neuchatel

U. of South Carolina

Zaragoza

SpokespersonEttore Fiorini

Milano

CUORE

CUORICINO×20 270 kg 130Te(~ 750 kg natTe)

0.001 / / /200

CUORICINOBG c keV y kg

Compact: 70×70×70 cm3

5 yr in Gran Sasso: <m> ~ 0.04 eV

APPROVED !

The Majorana ProjectDuke U.

North Carolina State U.

TUNL

Argonne Nat. Lab.

JINR, Dubna

ITEP, Moscow

New Mexico State U.

Pacific Northwest Nat. Lab.

U. of Washington

LANL

LLNL

U. of South Carolina

Brown

Univ. of Chicago

RCNP, Osaka Univ.

Univ. of Tenn.

Co-SpokespersonsFrank Avignone

Harry Miley

Majorana

0.5 ton of 86% enriched 76Ge

Very well known and successful technology

Segmented detectors using pulse shape discrimination to improve background rejection.

Prototype ready to go this autumn/winter. (14 crystals, 1 enriched)

100% efficient Can do excited state decay.

5 yr in a US undegr lab<m> ~ 0.03 eV

Enriched Xenon Observatory - EXO

U. of AlabamaCaltechIBM AlmadenITEP MoscowU. of NeuchatelINFN PadovaSLACStanford U.U. of TorinoU. of TriesteWIPP Carlsbad

SpokespersonGiorgio Gratta

Stanford

EXO

10 ton, ~70% enriched 136Xe 70% effic., ~10 atm gas TPC

or LXe chamber Optical identification of Ba

ion. Drift ion in gas to laser path

or extract on cold probe to trap.

200-kg enrXe prototype (no Ba ID) being built

Isotope in hand 5 yr in a US underground lab

<m> ~ 0.05 eV

Cadmium-Telluride O-neutrino double-Beta Research ApparatusCOBRA

Sussex

Oxford

Dortmund

Warwick

Project LeaderKai Zuber

Sussex

• CdTe or CdZnTe semiconductor detectors• Good E/E• Two isotopes 116Cd and 130Te• Operate at room temperature• New approach

• Large R&D programme needed• If successful can get to ~10-20 meV in ~ 20yr

SuperNEMO

UCLManchesterICLAL, OrsayBordeauxStrasbourgPragueITEP (Moscow)JINR (Dubna)Saga Univ. (Japan)INEEL (USA)MHC (USA)

• NEMO3 x 10 + better E/E• robust and developed technology• quick start (100 kg of isotope)

F ~ (E/E)6

Isotopes in SuperNEMO

Isotope Q, MeV

100Mo 3.033

82Se 2.995

116Cd 2.802

130Te 2.529

2 821/ 22 100

1/ 2

( )~ 10

( )

T Se

T Mo

Factor of 10 lower BG for 82Se

Can be produced in centrifuge - $30K-$50K/kg

SuperNEMO

4 supermodulesPlanar geometry

100 kg 82Se (Q = 3 MeV, large T1/2

2

Sensitivity ~0.04 eV in 5 yrFeasible if Zero BG experiment:

1) No BG from radioactivity the only possible BG from 2 tail (NEMO-III)2) Improve E/E from existing (14%-16%)/E to (8%-10%)/E Demonstrated (UCL+ Dubna)

Boulby mine is an attractive experimental site

SuperNEMO. Time Scale

2004 – 2005 scintillator R&D Attempt to reach 5-6%

2005-2006: Design study proposal (PPRP, Dec-Feb) Prototype submodule in

Boulby 2007-20010: Production 2009-2010: Start taking data 2014: planned sensitivity

~0.04 eV Excellent chance to be the

first to reach 40-50 meV

Concluding Remarks

Very exciting time for neutrino physics in general and 0 in particular

From oscillations: positive signal is a serious possibility

“Good value”: ~$50M for the great potential scientific gain

Several experiments with different isotopes are needed (recall NME uncertainties)