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n-NUCLEUS INTERACTIONS
OPEN QUESTIONS and FUTURE PROJECTS
Cristina VOLPE Institut de Physique Nucléaire
Orsay, France
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I. Motivation
II. Present Status, Open Questions
P L A N
III. Future Projects Low-energy Beta-beams
IV. Conclusions and Perspectives
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Different sources produce neutrinos whose
energies span various orders of magnitude.
Neutrino-Energy
We will focus on the low neutrino impinging
energies.
Cristina Volpe (IPN Orsay)
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Motivation n-Detector Response
Nuclei are often used as neutrino detectors in,
e.g. solar experiments, supernova observatories
or oscillation measurements.
EXAMPLE
Oscillation measurements
THE INTERPRETATION RELIES UPON PRECISE KNOWLEDGE
OF THE CROSS SECTIONS.
Cristina Volpe (IPN Orsay)
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Understanding Nucleosynthesis
The site where the heavy elements are
synthetized is not known.
Supernova type II explosions 99 of the energy
is emitted as neutrinos.
Calculations of abundances.
n-NUCLEUS INTERACTIONS ARE NEEDED.
Cristina Volpe (IPN Orsay)
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n-Nucleus Interactions Present status
Neutrinos probe nuclei over a wide energy range.
Nuclear Degrees of Freedom
Nucleon Degrees of Freedom
n-Energy
EFT, Microscopic Approaches (RPA, Shell Model),
EPT,
Fermi Gas
Experimental data are very scarce (deuteron and
iron, carbon). Theoretical predictions are
absolutely necessary.
The interpolation between these two regimes as
well as the extrapolation from stable to exotic
nuclei are needed !
Cristina Volpe (IPN Orsay)
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Constraints and Challenges
From other weak processes
b-decay
Very low momentum transfer (a few MeVs)
m-capture
Low momentum transfer (about 100 MeV)
EXAMPLE
From model-independent sum-rules, for some
states.
2
1-
BUT
Neutrinos can transfer a lot of energy to a
nucleus.
3-
1-
1
nm 12C 12N m-
0
N
C
LARGE SCALE CALCULATIONS ARE REQUIRED.
Cristina Volpe (IPN Orsay)
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ne 208Pb 208Bi e-
EXAMPLE
ltEne gt 15 MeV
2
1-
3-
1-
30 MeV
1
0
Bi
Pb
50 MeV
NEUTRINOS AS a PROBE for NUCLEAR STRUCTURE
STUDIES.
Cristina Volpe (IPN Orsay)
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(Other) Open Questions
Cristina Volpe (IPN Orsay)
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Is there a possibility to perform
systematic neutrino-nucleus interaction studies
at low energies?
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Neutrino beams can be produced with
enmne
mnm
m
p
CONVENTIONAL METHODS
STRATEGIES
6He 6Li e- ne
THE BETA-BEAM CONCEPT
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Lorentz boost
6He
6He
Q ?1/
g
high
Zucchelli, PLB 2002
Pure neutrino beams produced by boosting ions
which decay through beta-decay.
Cristina Volpe (IPN Orsay)
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Low-energy Beta-beams
Volpe, Journ. Phys. G. 30 (2004).
THE PROPOSAL
To exploit the beta-beam concept to produce
intense and pure low-energy neutrino beams.
A BETA-BEAM FACILITY FOR LOW-ENERGY NEUTRINOS.
Cristina Volpe (IPN Orsay)
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Possible Sites
Many laboratories will produce intense exotic
ion beams in the future.
g
Intensities
Detector
Storage Ring
1012 n/s
GANIL
1
4p
4p and Close detector
1-10
109 n/s
GSI
1-100
1012-14 n/s
CERN
CERN A UNIQUE SITE FOR THE n-INTENSITIES
ENERGIES.
Cristina Volpe (IPN Orsay)
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If a high-energy beta-beam is built
EURISOL
SPS
Storage Ring
Production and acceleration of exotic ions
Baseline Scenario at CERN
PS
B. Autin et al, J.Phys. G.
UNO
One of the possible scenarios
CP VIOLATION, PROTON DECAY, SUPERNOVA n.
Geneve
130 km
Italy
It can be part of it.
Cristina Volpe (IPN Orsay)
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n-Nucleus Interaction Rates
Neutrino Fluxes
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J. Serreau and C. Volpe, hep-ph/0403293.
g
ltEngt2gQb/2
Mass (tons)
Small Ring
Large Ring
Events per year for g14
35
25779
1956
ne D
952
82645
9453
ne 16O
360
103707
7922
ne 208Pb
Small Ring Lss 150 m, Ltot 450m Large Ring
Lss 2.5 km, Ltot 7.5 km
INTERESTING INTERACTION RATES CAN BE OBTAINED.
Cristina Volpe (IPN Orsay)
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The n-Magnetic Moment Prospects
THE LIMIT CAN BE IMPROVED BY ONE ORDER of
MAGNITUDE .
G.C. McLaughlin and C. Volpe, Phys. Lett. B 591
(2004).
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Conclusions and Perspectives
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Conclusions and Perspectives
Just approved !
More to come