PROSPECTS for detecting a

1
PROSPECTS for detecting a
NEUTRINO MAGNETIC MOMENT with
a TRITIUM SOURCE and BETA-BEAMS
Cristina VOLPE (Institut de Physique Nucléaire
ORSAY)
2
Low-energy beta-beams, Possible sites
Neutrino magnetic moment Present limits
P L A N
Prospects for mn Tritium source and low-energy
beta-beams
Conclusions and Perspectives
3
Low-energy beta-beams
C. Volpe, hep-ph/0303222.
THE PROPOSAL
To exploit the beta-beam concept to produce
intense and pure low-energy neutrino beams.
PHYSICS POTENTIAL
Neutrino-nucleus interaction studies are one
of the possible axis of research.
e
ne
C
N
Neutrino properties.
4
Possible sites
g
Detectors
Intensities
GANIL
1012 n/s
1
4p
A. Villari (GANIL)
EURISOL
1012-13 n/s
1
4p
4p and Close detector
109 n/s
1-10
GSI
H. Weick (GSI)
4p and Close detector
CERN
1-100
1012-13 n/s
Autin et al, J.Phys. (2003).
A PROPOSAL for a LOW-ENERGY BETA-BEAM facility.
5
Neutrino magnetic moment
mn 3.2 x 10-19 (mn/1 eV) mB
Indirect limits
mn lt 5. x 10-11 mB
- Nucleosynthesis
Morgan (1981), Fukugita and Yazaki (1987),
mn lt 3. x 10-12 mB
- Stellar Cooling
Raffelt (1990),
mn lt 1.5-5 x 10-12 mB

• Supernovae II explosions
• (SN1987A)

Lattimer and Cooperstein (1988), Goldman et al.
(1988), Notzold (1988),
6
Neutrino magnetic moment Direct observation
e
ne
e
n
n
ne
g
W
Neutrino-electron scattering
e
e
WEAK
MAGNETIC
The presence of a magnetic moment introduces in
ne-e scattering, a 1/T-like divergence, where T
is the electron recoil energy.
7
Neutrino magnetic moment Direct limits
e
ne
e
ne
Present best limits are from reactor
experiments.
mn lt 1.3 x 10-10 mB (90 C.L.)
Phys. Rev. Lett.90 (2003) TEXONO
Collaboration Kuo-Sheng Reactor
Similar limits JETP Lett. 55 (1992) Kurchatov
Reactor
JETP Lett. 57 (1993) Rovno Reactor
mn lt 1.0 x 10-10 mB (90 C.L.)
PRESENT LIMIT FROM DIRECT MEASUREMENTS mn lt
1.0 x 10-10 mB.
MUNU Collaboration, PLB (2003) Bugey Reactor
8
Prospects for mn Tritium source
3H
3Heene Qb18.6 KeV
10-11 mB
10-12 mB
Giomataris, hep-ex/ 0303045.
Number of ne-e events with a 200 Mcurie (20 Kg)
Tritium source and a 4p low-threshold detector
(e.g. TPC or cryogenic).
mn 0
THE LIMIT of a few x 10-12 mB CAN BE OBTAINED.
G.C. McLaughlin and C. Volpe, hep-ph/0303222.
9
Prospects for mn Low-energy Beta-beams
ne-e events with beta-beams (10 15 n/s) with a 4p
low-threshold detector.
6He
6Liene Qb4. MeV
5 x 10-11 mB
5 X 10-11 mB
10-10 mB
mn 0
10-11 mB
THE LIMIT of a few x 10-11 mB CAN BE OBTAINED.
G.C. McLaughlin and C. Volpe, hep-ph/0303222.
10
Reactor Experiments
5 x 10-11 mB
Li and Wong, J.Phys.G28(2002)1453.
MUNU
R15-100 keV R20.5-2.MeV
10-10 mB
Kou-Sheng
mn 0
Uncertainty on the (lt3 MeV) n-flux
A better understanding of the low-energy (less
than 3 MeV) component of the reactor neutrino
flux is needed.
11
Conclusions
The direct measurement of a neutrino
magnetic moment needs - intense and
well-understood neutrino fluxes - very
low-threshold detectors.
Improved limits of a few x 10-12 mB and a few x
10-11 mB can be achieved with a 20oMCi tritium
source and low-energy beta-beams respectively.
12
Perspectives
Neutrino-nucleus interactions at a low-energy
beta-beam facility
J. Serreau and C. Volpe, in preparation.
13
WORKSHOP at ECT (TRENTO, Italy) 18-22 October
2004
EXPLORING THE IMPACT of NEW NEUTRINO BEAMS
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,
Organizers C. Volpe (Coordinator) J. Bouchez,
M. Lindroos, M. Mezzetto,T. Nillson.