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Curien D.,CNRS Hubert Curien Multi-disciplinary Institute | Dudek J.,CNRS Hubert Curien Multi-disciplinary Institute | Molique H.,CNRS Hubert Curien Multi-disciplinary Institute | Sengele L.,CNRS Hubert Curien Multi-disciplinary Institute | And 2 more authors.
International Journal of Modern Physics E | Year: 2011

Following a series of experiments launched by the TetraNuc collaboration to possibly demonstrate the existence of high-rank symmetries in subatomic physics, the first experimental results on the Rare Earth region appear in publications. Meanwhile an important progress has been made on the theory side strongly suggesting that the original criterion of the static tetrahedral symmetry in the form of vanishing quadrupole moments may need to be revised to include explicitly the vibrational motion. The Actinide region seems of particular interest because of the extra stability provided by the octahedral symmetry. In this article a summary of the current experimental efforts on both the Rare-Earth and Actinide regions is given. Finally the ELMA project addressing the experimental search for the symmetries in the Actinides is briefly discussed. © 2011 World Scientific Publishing Company.

Sadhukhan J.,University of Tennessee at Knoxville | Sadhukhan J.,Oak Ridge National Laboratory | Mazurek K.,University of Tennessee at Knoxville | Mazurek K.,Oak Ridge National Laboratory | And 13 more authors.
Physical Review C - Nuclear Physics | Year: 2013

The spontaneous fission lifetime of 264Fm has been studied within nuclear density functional theory by minimizing the collective action integral for fission in a two-dimensional quadrupole collective space representing elongation and triaxiality. The collective potential and inertia tensor are obtained self-consistently using the Skyrme energy density functional and density-dependent pairing interaction. The resulting spontaneous fission lifetimes are compared with the static result obtained with the minimum-energy pathway. We show that fission pathways strongly depend on assumptions underlying collective inertia. With the nonperturbative mass parameters, the dynamic fission pathway becomes strongly triaxial and it approaches the static fission valley. On the other hand, when the standard perturbative cranking inertia tensor is used, axial symmetry is restored along the path to fission; an effect that is an artifact of the approximation used. © 2013 American Physical Society.

Mazurek K.,Niewodniczanski Institute of Nuclear Physics | Mazurek K.,French Atomic Energy Commission | Schmitt C.,French Atomic Energy Commission | Wieleczko J.P.,French Atomic Energy Commission | And 2 more authors.
Physical Review C - Nuclear Physics | Year: 2011

The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. When utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed. © 2011 American Physical Society.

Avdeyev S.P.,Joint Institute for Nuclear Research | Karnaukhov V.A.,Joint Institute for Nuclear Research | Oeschler H.,TU Darmstadt | Kirakosyan V.V.,Joint Institute for Nuclear Research | And 5 more authors.
Bulletin of the Russian Academy of Sciences: Physics | Year: 2010

The relative velocity correlation function of pairs of intermediate mass fragments has been studied for d + Au collisions at 4.4 GeV. Experimental correlation functions are compared to that obtained by multi-body Coulomb trajectory calculations under the assumption of various decay times of the fragmenting system. The combined approach with the empirically modified intranuclear cascade code followed by the statistical multifragmentation model was used to generate the starting conditions for these calculations. The fragment emission time is found to be less than 40 fm c-1. © Allerton Press, Inc., 2010.

Pellegri L.,University of Milan | Pellegri L.,National Institute of Nuclear Physics, Italy | Bracco A.,University of Milan | Bracco A.,National Institute of Nuclear Physics, Italy | And 53 more authors.
Physical Review C - Nuclear Physics | Year: 2015

A multitude of discrete 2+ states in Sn124 with energy up to 5 MeV were populated and identified with the (O17, O′17γ) reaction at 340 MeV. Cross sections were compared with distorted wave Born approximation predictions and in general a good agreement was found. The measured energy and intensity distributions of the 2+ states are very similar to the predictions based on self-consistent density functional theory and extended QRPA approach accounting for multiphonon degrees of freedom. This provides evidence of the excitation of the pygmy quadrupole resonance in skin nuclei. © 2015 American Physical Society.

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