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NuPECC Meeting, Zagreb, 13.-14.6.2008.
Modern Theory of Exotic
Structure:
NuclearNuclear
Structure,
Exotic
Modern Theory
ofInteraction
Nuclear Structure,
Exotic
Excitations,
Weak
Rates
and
Beyond
Excitations and Neutrino-Nucleus Reactions
Excitations and Neutrino-Nucleus Reactions
N. Paar
Physics Department
Faculty of Science
University of Zagreb
Croatia
www.phy.hr/~npaar
BEYOND THE MEAN FIELD
DESCRIPTION OF NUCLEAR QUANTUM PHASE TRANSITIONS
RMF+GCM
Transitions between
spherical and axially
deformed shapes
COLLECTIVE EXCITATIONS IN NUCLEI: GIANT RESONANCES
Self-consistent description of
excitations : relativistic quasiparticle
random phase approximation (RQRPA)
IVGDR
ISGMR
EXOTIC MODES OF EXCITATION IN NUCLEI
exotic nuclei are characterized by weak binding of outermost nucleons,
diffuse neutron densities, formation of the neutron skin and halo
effect on multipole response → new exotic modes of excitation
PYGMY DIPOLE RESONANCE (PDR)
Among the low-lying states, a
single state has more distributed
structure composed of many
transitions from weakly bound
neutron orbitals
→ REVIEW: Paar, Vretenar, Khan, Colò, Rep. Prog. Phys. 70, 691 (2007).
PYGMY DIPOLE RESONANCES AND NEUTRON SKIN
● Adrich et al., PRL 95, 132501(2005).
1  2 E ( , )
S2 ( ) 

 0
2  2
p
K 0
2
 a4  02 (    0 ) 
(



)
 ...
0
2
0
18  0
|
Result (averaged 130,132Sn) :
a4 = 32.0 ± 1.8 MeV
Klimkiewicz, Paar, et al. PRC 76, 051603(R) (2007)
PYGMY DIPOLE RESONANCES AND NEUTRON SKIN
Sn isotopes
LAND
Rn – Rp :
A.Krasznahorkay et al.
PRL 82(1999)3216
130Sn:
0.23 ± 0.04 fm
132Sn:
0.24 ± 0.04 fm
EXOTIC MODES TOWARDS THE PROTON DRIP-LINE
PROTON PYGMY
DIPOLE RESONANCE
Centroid energy
and B(E1) for
low-lying states
Proton PDR is composed from transitions of weakly bound protons
including those which are bound only due to the Coulomb barrier
Paar, Vretenar, Ring, Phys. Rev. Lett. 94, 182501 (2005)
NEUTRINO-NUCLEUS REACTIONS
E
Reduced matrix elements for the neutrinonucleus cross section:
0+
ZXN
RQRPA amplitudes
32+
210+
1+
Z+1XN-1
RHB occupation probabilities
Possible extrapolations
towards exotic nuclei
relevant for astrophysics
without any adjustments
of interaction parameters
DISTRIBUTION OF CROSS SECTIONS OVER MULTIPOLARITIES
RHB+RQRPA
The knowledge on
spin-dipole excitations
and higher multipolarities
is essential for reliable
description of neutrino
nucleus cross sections!
Paar, Vretenar, Marketin, Ring Phys. Rev. C 77, 024608 (2008)
ne-NUCLEUS CROSS SECTIONS AVERAGED OVER NEUTRINO FLUX
ne FLUX
Experimental
flux of neutrinos
obtained from m+
decay at rest
MUON NEUTRINO CAPTURE, EXOTIC ATOMS, …
(νμ,μ-)
<σ>(10-40cm2)
RPA(Volpe et al.)
19.23
QRPA(Volpe et al.)
20.29
CRPA(Kolbe et al.)
18.18
PN-RQRPA
10.97
EXP.(LSND)
12±0.3±1.8
Self-consistent description of muon atom:
nm FLUX
CROSS SECTIONS FOR SUPERNOVA NEUTRINOS
Supernova neutrino flux:
5
Cross section averaged over
Supernova neutrino flux
4
3

2
1
0
2
4
6
T[MeV]
8
10
CONCLUDING REMARKS
Unified description of the structure of stable and nuclei far from
stability, and reliable extrapolations toward the drip lines
When extended to take into account the most important correlations,
it describes deformations and shape-coexistence phenomena
associated with shell evolution
Insight into dynamics of exotic modes of excitation, neutrinonucleus reactions, weak interaction rates of relevance for nuclear
astrophysics
www.phy.hr/~npaar
T. Nikšić, T. Marketin, D. Vretenar, Zhipan-Li
University of Zagreb, Croatia
G. A. Lalazissis
Aristotle Universtity of Thessaloniki, Greece
P. Ring
Technische Universitaet Muenchen, Germany
G.Colò
Università degli Studi and INFN, Milano, Italy
E. Khan
IN2P3-CNRS/Université Paris-Sud, Orsay, France