PROSPECTS for detecting a

NEUTRINO MAGNETIC MOMENT with

a TRITIUM SOURCE and BETA-BEAMS

Cristina VOLPE(Institut de Physique Nucléaire ORSAY)

Low-energy beta-beams,Possible sites

PLAN

Neutrino magnetic moment :Present limits

Prospects for :Tritium source and low-energy beta-beams

Conclusions and Perspectives

Low-energy beta-beams

To exploit the beta-beam concept to produce intense and pure low-energy neutrino beams.

THE PROPOSAL

C. Volpe, hep-ph/0303222.

PHYSICS POTENTIALNeutrino-nucleus interaction studies are one ofthe possible axis of research.

eeC N

Neutrino properties.

Possible sites

CERN

GANIL

EURISOL

GSI

Intensities Detectors

1012 /s 1 4

1012-13 /s 1 4

1012-13 /s 1-100

109 /s 1-10 4andClosedetector4andClosedetector

Autin et al,J.Phys. (2003).

H. Weick (GSI)

A. Villari (GANIL)

A PROPOSAL for a LOW-ENERGY BETA-BEAM facility.

Neutrino magnetic moment

Indirect limits :

= 3.2 x 10-19 (m1 eV B

< 5. x 10-11 B- Nucleosynthesis

- Stellar Cooling

- Supernovae II explosions (SN1987A)

Morgan (1981), Fukugita and Yazaki (1987),…

< 3. x 10-12 B

Raffelt (1990),…

< 1.5-5 x 10-12 B

Lattimer and Cooperstein (1988), Goldmanet al. (1988), Notzold (1988),…

W

l

Neutrino magnetic moment :Direct observation e

ee

e

Neutrino-electron scattering

22 eFmG

dtd

2

22222 1

ve

VAvAVAV

ETmggE

Tgggg

TET

me /1

2

2

WEAK

MAGNETIC

The presence of a magnetic moment introduces in e-e scattering, a 1/T-like divergence, where T is the electron recoil energy.

e

W

e

E

T

T/1

Present best limits are from reactor experiments.

< 1.3 x 10-10 B

(90 %C.L.)Phys. Rev. Lett.90 (2003)TEXONO CollaborationKuo-Sheng Reactor

Neutrino magnetic moment : Direct limits

PRESENT LIMIT FROM DIRECT MEASUREMENTS: < 1.0 x 10-10 B.

< 1.0 x 10-10 B (90

%C.L.)MUNU Collaboration, PLB (2003)Bugey Reactor

Similar limits :JETP Lett. 55 (1992)Kurchatov Reactor

JETP Lett. 57 (1993) Rovno Reactor

eee

eE

T

Prospects for Tritium source

G.C. McLaughlin and C. Volpe, hep-ph/0303222.

Number of e-e events with a 200 Mcurie (20 Kg) Tritium source and a 4 low-threshold detector (e.g. TPC or cryogenic).

THE LIMIT of a few x 10-12 B CAN BE OBTAINED.

Giomataris, hep-ex/ 0303045.

10-11 B

10-12 B

= 0

3H 3He+e+e QKeV

Prospects for Low-energy Beta-beams

G.C. McLaughlin and C. Volpe, hep-ph/0303222.

THE LIMIT of a few x 10-11 B CAN BE OBTAINED.

10-10 B

= 0

5 x 10-11 B

10-11 B

5 X 10-11 B

e-e events with beta-beams (10 15 /s) with a 4 low-threshold detector.

6He 6Li+e+e QMeV

Reactor Experiments

5 x 10-11 B

10-10 B

= 0

MUNU

Kou-Sheng

Uncertainty on the (<3 MeV) -flux

R1=5-100 keVR2=0.5-2.MeV

Li and Wong, J.Phys.G28(2002)1453.

A better understanding of the low-energy (less than 3 MeV) component of the reactor neutrino flux is needed.

Conclusions

The direct measurement of a neutrino magneticmoment needs : - intense and well-understood neutrino fluxes; - very low-threshold detectors.

Improved limits of a few x 10-12 B and a few x 10-11 B can be achieved with a 20oMCi tritium source and low-energy beta-beams respectively.

Perspectives

“Neutrino-nucleus interactions at a low-energy beta-beam facility”

J. Serreau and C. Volpe, in preparation.

WORKSHOP at ECT* (TRENTO, Italy)18-22 October 2004

“EXPLORING THE IMPACT of NEW NEUTRINO BEAMS”

Organizers : C. Volpe (Coordinator)J. Bouchez, M. Lindroos,M. Mezzetto,T. Nillson.

Goals Present status and future projects in neutrino and nuclear physics The feasibility and physics potential of neutrino factories, super- beams, beta-beams and low-energy beta-beams

The impact in other fields, among which hadron physics, muon physics, baryogenesis and leptogenesis, nucleosynthesis, …