Proposal to join NEMO-3 decay experiment

P. Adamson, R. Saakyan, J. Thomas

UCL27 January 2003

Outline Motivation decay basics Short term future for experiments NEMO-III detector Future experiments Possible UK involvement in NEMO-III Costs

Motivation

Neutrino oscillations

2.510-3 eV2

510-5 eV2

510-5 eV2

2.510-3 eV2

mscale = 0.01 eV mscale = 0.05 eV

Motivationneutrino oscillations can not measure:

Nature of neutrino mass = bar (Majorana) OR bar (Dirac)

Absolute mass scale decayDirect kinematic searches (3H decay)

UK Involvement. Current Picture

M IN O S S N O S ou d an II

N eu tirn o O sc illa tion s

K A TR IN(P rop osa l)

Trit iu m D ecay

N O IN V O L V E M E N T

D ou b le B eta D ecay

M ass ive N eu trin o P h ys ics

decay basics

T0.5~ 1020 yr T0.5 > 1025 yr

Find isotopes where (A,Z)(A,Z+2) is energetically allowed, but forbidden in steps (A,Z)(A,Z+1)(A,Z+2)

decay basics Average Majorana mass:

m depends on sum over U

2*m

If large, could be dominated by Ue32m3

(depends on hierarchy)

2 222 2 i

N N

ei i ei ii i

m U m U e m

Majorana CP phasesMixing matrix

1 20 0 0 21/ 2 ( )T G Q M m

Phase spaceNuclear matrix elementQ

48Ca, 76Ge, 100Mo, 150Nd,136Xe, 116Cd, 96Zr, 82Se,130Te

Due to uncertainties in M0 we have to study as manyisotopes as possible!

(0.35 – 1 eV)

Tkin(e-+e-)

(A,Z) (A,Z+2) + e- + e- + bar + bar 2

(A,Z) (A,Z+2) + e- + e- 0

(A,Z) (A,Z+2) + e- + e- + 0 0(Majoran)

A look at short term future decay experiments

3H expts sensitivity in ~ 2008

Future projects: CUORE, Majorana, EXO, etc to have 0.05 eV sensitivity (~ 2008 – 2010)

mscale ~ 0.01 – 0.05 eVfrom oscillation expts

Short-term future: now - 2007

<m> = 0.4 eVHeidelberg-Moscow Experiment“Evidence” strongly criticized by community

Not background free region

NEMO-3

CUORICINOby 20070.1 – 0.7 eV 130Te (34%) natural abundance, good bolometric properties

NEMO-3 Collaboration

50 physicists and engineers

12 Laboratories/Universities

5 Countries

250ps t timing from plasma propagation in tracker, z = 1cm x, y = 100m,

Data taking2e events

Data takingBackground events

208Th <.02mBq/kg

214Bi < .3mBq/kg

These have HE electron, but not same topology,or timing

Excited states O() less common, used to measure NME

October visit summary: Significant shortage in manpower for data analysis. We are welcome to start right away

Somewhat involved analysis• detection (105 2 events/y !!! for 100Mo)• BG rejection techniques• Source contamination measurements (for future developments)

Running since June’02 but only 200 hrs 100Mo carefully analysed

Possible UK involvement in data analysis

Isotopes “distributed” between institutions

We are suggested to take up analysis of 82Se (NEMO3 upgrade isotope)

Isotope Mass, g100Mo 7200130Te 130082Se 1000

116Cd 600150Nd 5096Zr 2048Ca 10

NEMO-3 0 sensitivity5 years

100Mo

7 kg Q =3.034 MeV

External BG: 0 Internal BG:

radioactivity < 0.04 event/y/kg = 0.11 event/y/kg

T1/2 > 5 × 1024 yr

<m> < 0.2 – 0.7 eV

E = 2.8 – 3.2 MeV 82Se

1 kg Q =2.995 MeV

External BG: 0 Internal BG:

radioactivity < 0.01 event/y/kg = 0.01 event/y/kg

T1/2 > 1 × 1024 yr

<m> < 0.6 – 1.2 eV

Possible UK involvementUpgrade of NEMO-3

2 821/ 22 1001/ 2

( )10

( )

T Se

T Mo

12 kg 82Se Why 82Se?

And theory says there isNO 2 0

1/ 2 1/ 2T T scaling

Improve S/B by ~10 Sensitivity <m>~0.14 eV in 5 yr

SuperNEMO

Sensitivity <m> ~ 0.05 eV in 5 yr

~ 100 kg 82Se (or other)

4 supermodules, planar geometry

Feasible if:a) BG only from 2 (NEMO3)b)E/E = 10-11% at 1 MeV

(R&D needed)

Future projects comparison“Conservative” approach

Experiment Source and Mass

Sensitivity toT1/2 (y)

Sensitivity to<m> (eV)*

Majorana$50M

76Ge, 500kg

3×1027 0.03 – 0.07

CUORE$25M,long

130Te, 750kg(nat)

2×1026 0.05 – 0.17

EXO(or other Xe-expt)

136Xe1 ton

8×1026 0.05 – 0.12

SuperNEMO$20M

82Se(or other)

100 kg2×1026 0.05 – 0.11

* 5 different latest NME calculations

SuperNEMO – UK involvementScintillator R&D

Improving E/E from 9% to 6% (at 3 MeV) will reduce BG by a factor of ~ 10

Increase light output Scintillator studies Light collection PMT-scintillator optical couplingPMT studies

matches our experience (MINOS)

6

(2 )E

FractionQ

Responsibilities2003-2004 MC of 2e and BG events from 82Se (Saakyan, New

PostDoc) Off-line DA for 82Se, cross-check with other isotopes

(Adamson, NewPostDoc, Saakyan, Thomas) Laser LI calibration/monitoring (Adamson, Thomas) Scintillator R&D for SuperNEMO (Saakyan, Thomas,

NewPostDoc, Technician) DAQ/electronics for R&D setup (Adamson,

NewPostDoc, Software Engineer) DA from R&D setup (Adamson, NewPostDoc,

Saakyan, Thomas)

Costs

Item 2003 2004

Rolling Grant Costs

UCL staffSaakyan

05%30%

05%30%

Extra costs to PPARC

EquipmentTravelResponsive RA

£10K£5K£50K

£10K£5K£50K

PPARC Fellows

AdamsonThomas

30%30%

30%30%

Concluding Remarks is the only practical approach for

Majorana ‘s Participation in NEMO-3 is a good

opportunity to understand feasibility of this technique…

…and to put UK in the DBD arena NEMO-3 will confirm or rule out H-M result

(0.1-0.2eV depending on Se availability) Next generation DBD experiments to probe

~ 0.05 eV scale NEMO technology orthogonal to other

competitors

Concluding Remarks II

Window of opportunity with MINOS for authors (beam due end of 04)

Possibility to analyse data this week!

Results will be competitive (many isotopes, orthogonal approach)

This proposal does not commit us to Super-NEMO