exotic nuclei structure and reaction noyaux exotiques ... - IPN - IN2P3

[1] A.B. Balantein, J. Gava, C. Volpe, Phys. Lett.B,
662, 396 (2008), e-Print: arXiv:0710.311.
[2] J. Gava, C. Volpe, Phys. Rev. D 78, 083007
(2008).
e-Print: arXiv:0807.3418 [astro-ph]
[3] J. Gava, PhD Thesis, June 2009. “Neutrino
properties in the astrophysical and cosmological
contexts.”Supervisor: C. Volpe
In [4] we have extended our results obtained in
the context of core-collapse supernova and applied
them in the cosmological context. We have explored
for the first time possible CP violation effects
on the neutrino degeneracy parameter at the
epoch of Big-Bang nucleosynthsis (BBN). First we
have demonstrated that there can be effects coming
from the Dirac phase of the MNSP matrix on
the neutrino degeneracy parameter (related to the
neutrino-antineutrino asymmetry) if the muon and
tau neutrino degeneracy parameter are not equal
just before the BBN epoch. We have then performed
numerical calculations of their evolution including
vacuum mixing, coupling to the relativistic
plasma and collisions (in the damping approximation).
Our results show that effects coming from the
Dirac phase on the neutrino degeneracy parameter—and
the helium 4 fraction - are at the level of
10 -4 and 10 -3 respectively. Note that the He-4 abundance
is currently known with a precision at the
level of 10% .
[4] J. Gava, C. Volpe, to appear in Nucl. Phys. B,
arXiv: 1002. 0981 .
Searching for the third unknown mixing angle
The study of neutrino propagation in dense media
is currently a fast developing field where major progress
is ongoing. This is due to the realization of
calculations that include the neutrino coupling to
neutrinos on one hand and the use of temporally
evolving density profiles on the other. New phenomena
have shown to emerge, namely collective
flavour conversion effects and multiple resonances
and phase effects. The picture is very different
from the case of our Sun. These two lines of research
have been parallel so far. We have performed
the very first calculations including both the
neutrino-neutrino and shock wave effects, following
the neutrino amplitudes through the star. We
have indentified an interesting signature of the
third neutrino mixing angle in the time signal associated
to electron anti-neutrino scattering on protons
which is the dominant detection channel for
water Cherenkov and scintillator detectors. Dip
(bumps) appear when the shock wave passes
through the MSW resonance region for positron
having energies lower (larger) than 20 MeV. Such
a signature can be identified in a running detector
such as Super-Kamiokande if the third neutrino
mixing angle is smaller than 10 -5 and the hierarchy
is inverted. This work is an example of the complpementarity
between terrestrial and astrophysical
searches.
At IPN, we are at present among the leading
groups able to follow (in the single angle approximation)
the 3 flavour neutrino evolution including
the coupling to matter and to the neutrinos, keeping
all phases during the evolution.
[1] J. Gava, J. Kneller, C. Volpe, G.C. McLaughlin,
Phys. Rev. Lett. 103, 071101 (2009), e-print:arXiv:
0902.0317.
Untangling core-collapse supernova signals
with beta-beam data
Low energy beta-beams is a new facility for the
production of neutrinos in the 100 MeV energy range
[1], based on the novel concept of beta-beams
proposed by Zucchelli [2]. This exploits the betadecay
of boosted radioactive ions. While the original
baseline scenarios aims at the search for leptonic
CP violation, low energy beta-beam physics
program covers timely open issues in the study of
nuclear structure, of fundamental interactions and
of core-collapse supernova physics. For a review
of beta-beams and their physics potential see [3].
The feasibility of beta-beams and the physics
potential of low energy beta-beams have been investigated
within the EURISOL Design Study in
FP6 (2005-2009). The neutrino group at IPN has
contributed significantly to the study of the physics
potential of low energy beta-beams [4].
In [5] we have been showing that, by performing
systematic measurements of neutrino-nucleus interactions
with different gammas of the ions, one can
fit future supernova neutrino signals and extract
information from neutrino oscillation parameters.
The established procedure is not affected by the
uncertainties inherent to the neutrino-nucleus
cross sections.
[1] C. Volpe, Journ. Phys. G 30, L1 (2004), arXiv:
0303.222 .
[2] P. Zucchelli, Phys. Lett. B 532, 166 (2002).
[3] C. Volpe, Progress in Particle and Nuclear Physics,
(2010) arXiv: 0911.4314 .
[4] « The EURISOL Design Study Technical Advanced
Report », FP6, 2009.
[5] N. Jachowicz, G.C. McLaughlin, C. Volpe,
Phys. Rev. D 77, 055501 (2008), arXiv:
0804.0360 .
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