122106279
Pairing properties of hot nuclei within the finite temperature Hartree Fock+BCS approximation
In this work, finite temperature Hartree Fock BCS (FT+HFBCS) calculations are performed in Sn isotopes with the zero-range Skyrme type interactions. Vanishing of pairing correlations due to the increase in temperature are investigated with various types of Skyrme interactions. In addition, dependence of the critical temperature with respect to the several properties of these energy density functionals are analysed.
118388834
Density functional theory studies of cluster states in nuclei
The framework of nuclear energy density functionals is applied to a study of the formation and evolution of cluster states in nuclei. The relativistic functional DD-ME2 is used in triaxial and reflection-asymmetric relativistic Hartree-Bogoliubov calculations of relatively light $N=Z$ and neutron-rich nuclei. The role of deformation and degeneracy of single-nucleon states in the formation of clusters is analyzed, and interesting cluster structures are predicted in excited configurations of Be, C, O, Ne, Mg, Si, S, Ar, and Ca $N=Z$ nuclei. Cluster phenomena in neutron-rich nuclei are discussed, and it is shown that in neutron-rich Be and C nuclei cluster states occur that are characterized by molecular bonding of $\ensuremath{\alpha}$ particles by the excess neutrons.
122058801
Nuclear clustering in the Energy Density Functional Approach
Nuclear Energy Density Functionals (EDFs) are a microscopic tool of choice extensively used over the whole chart to successfully describe the properties of atomic nuclei ensuing from their quantum liquid nature. In the last decade, they also have proved their ability to deal with the cluster phenomenon, shedding a new light on its fundamental understanding by treating on an equal footing both quantum liquid and cluster aspects of nuclei. Such a unified microscopic description based on nucleonic degrees of freedom enables to tackle the question pertaining to the origin of the cluster phenomenon and emphasizes intrinsic mechanisms leading to the emergence of clusters in nuclei.
118384659
Neutron specific heat in the crust of neutron stars from the nuclear band theory
The inner crust of neutron stars, formed of a crystal lattice of nuclear clusters immersed in a sea of unbound neutrons, may be the unique example of periodic nuclear systems. We have calculated the neutron-specific heat in the shallow part of the crust using the band theory of solids with Skyrme nucleon-nucleon interactions. We have also tested the validity of various approximations. We have found that the neutron-specific heat is well described by that of a Fermi gas, while the motion of the unbound neutrons is strongly affected by the nuclear lattice. These apparently contradictory results are explained by the particular properties of the neutron Fermi surface.
99403269
Crystal, cluster and quantum liquid nuclear states
Nuclear states are often described as quantum liquid states. Using the localisation parameter, it is possible to understand cluster states in nuclei as hybrid states between quantum liquid and crystal states. Recent calculations discussing the effect of the depth of the confining potential, as well as various lengthscales ratios, are presented in order to provide a complementary view on the cluster phenomenon in nuclei.
119083518
Probing the 6He halo structure with elastic and inelastic proton scattering
Abstract Proton elastic and inelastic scattering to the first excited state of 6 He have been measured over a wide angular range using a 40.9 A  MeV 6 He beam. The data have been analyzed with a fully microscopic model of proton–nucleus scattering using 6 He wave functions generated from large space shell model calculations. The inelastic scattering data show a remarkable sensitivity to the halo structure of 6 He.
16602751
Extragalactic cosmic-ray source composition and the interpretation of the ankle
We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear chart. We confirm earlier results showing that the high-energy data can be fit with a pure proton extragalactic cosmic ray (EGCR) component if the source spectrum is $\propto E^{-2.6}$. In this case the ankle in the cosmic ray (CR) spectrum may be interpreted as a pair-production dip associated with the propagation. We show that when heavier nuclei are included in the source with a composition similar to that of Galactic cosmic-rays (GCRs), the pair-production dip is not present unless the proton fraction is higher than 85%. In the mixed composition case, the ankle recovers the past interpretation as the transition from GCRs to EGCRs and the highest energy data can be explained by a harder source spectrum $\propto E^{-2.2}$-- $E^{-2.3}$, reminiscent of relativistic shock acceleration predictions, and in good agreement with the GCR data at low-energy and holistic scenarios. While the expected cosmogenic neutrino fluxes at high energy are very similar for pure proton and mixed composition hypothesis, the two scenarii predict very different elongation rates from $10^{17.5}$ to $10^{20}$ eV.
18494833
Photodisintegration of ultra-high-energy cosmic rays revisited
Abstract Recent microscopic and phenomenological calculations of giant dipole resonances for A  ⩽ 56 nuclei are presented. The derived photodisintegration cross sections are exhaustively compared to the photonuclear data available to date. An accurate description of the data is found. Our new calculations are also compared with the previous and widely-used estimates of Puget, Stecker and Bredekamp. The present calculations also include all the possible paths down the nuclear chart. The impact on the photodisintegration of ultra-high-energy cosmic rays (UHECR) is illustrated for a Fe source with typical energies of 10 20 –10 21  eV. At energies around 10 20  eV, the new cross sections are found to modify the UHECR photodisintegration rates. At energies around 10 21  eV, it is recommended to solve a full reaction network to estimate the photodisintegration rate of the UHECR.
10213979
UHE nuclei propagation and the interpretation of the ankle in the cosmic-ray spectrum
We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear chart. We confirm earlier results showing that the high-energy data can be fit with a pure proton extragalactic cosmic ray (EGCR) component if the source spectrum is ∝E −2.6 . In this case the ankle in the CR spectrum may be interpreted as a pair-production dip associated with the propagation. We show that when heavier nuclei are included in the source with a composition similar to that of Galactic cosmic-rays (GCRs), the pair-production dip is not present unless the proton fraction is higher than 85%. In the mixed composition case, the ankle recovers the past interpretation as the transition from GCRs to EGCRs and the highest energy data can be explained by a harder source spectrum ∝E −2.2 –E −2.3 , reminiscent of relativistic shock acceleration predictions, and in good agreement with the GCR data at low-energy and holistic scenarios.