121772448
Challenging nuclear structure models through a microscopic description of proton inelastic scattering off 208Pb
A fully microscopic calculation of inelastic proton scattering off {sup 208}Pb is presented, and compared to experimental scattering data for incident proton energies between 65 and 201 MeV. By constructing the nucleon-nucleus interaction through the folding of nuclear structure information with a reliable nucleon-nucleon effective interaction that has no adjusted parameter, a consistent framework is built, for probing the influence of different descriptions of nuclear structure on nucleon inelastic scattering predictions. The absence of phenomenological normalization in this framework guarantees a unique and unambiguous interpretation of our calculations in terms of quality of the underlying nuclear structure description: a feature that had been reserved, until recently, to the electron probe. This tool is used to investigate the effect of long range correlations embedded in excited states, on calculated inelastic observables, demonstrating the sensitivity of nucleon scattering predictions to details of the nuclear structure.
120568906
QRPA CALCULATIONS FOR SPHERICAL AND DEFORMED NUCLEI WITH THE GOGNY FORCE
Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed with the D1S Gogny force. Impact of the deformation in giant multipole resonances is discussed. QRPA and 5 Dimensional Collective Hamiltonian results are compared for low lying 2+ states in N = 16 isotones and Ni isotopes. Multipole resonances are also obtained for the heavy nucleus 238U.
117160842
Microscopic description of elastic and inelastic proton scattering from 208pb
Information on the equation of state (EOS) of neutron matter may be gained from studies of 208Pb. Descriptions of 208Pb require credible models of structure, taking particular note also of the spectrum. Such may be tested by analyses of scattering data. Herein, we report on such analyses using an RPA model for 208Pb in a folding model of the scattering. No a posteriori adjustment of parameters are needed to obtain excellent agreement with data. 
From those analyses, the skin thickness of 208Pb is constrained to lie in the range 0.13-0.17 fm.
53446943
Status report on ECR ion source operation at GANIL
Two electron cyclotron resonance ion sources, ECR 4 and ECR 4 M, provide high charge state beams to the compact cyclotrons, C01 and C02, which are alternative injectors for the GANIL cyclotrons CSS1 and CSS2. When an injector runs for a long period, the off-line source can be used for beam developments or, together with the off-line injector, deliver a beam to a new beam line, called IRRSUD, for atomic physics experiments. Various ions are requested for beam time for periods of 8 to 11 weeks. Although the majority of the required beams comes from gaseous elements, work on the production of beams of metallic ions is always a main activity. New ovens are being developed to improve the capacity and the performances of the standard micro-oven. The latest results with 238U beam, using sputtering method and 76Ge beam using recycling method, are reported here.
121877783
Production of metallic ions with an ECRIS at GANIL
A summary of recent and future developments in metallic ion production with an electron cyclotron resonance ion source (ECRIS) at GANIL is presented. Multicharged metallic ions are routinely produced with an ECRIS (ECR4 14 GHz) and accelerated for nuclear and atomic physics experiments. We present the various methods which have been used to generate these multicharged metallic ions. The accelerator requires stable beams for periods of weeks. The results obtained recently by direct ion plasma sputtering of Ni, Nb, and U samples are remarkable and stable beams from these metals have been delivered continuously for weeks. A pulsed EXCIMER laser, injecting a beam axially through the extraction hole of the ECRIS, has been tested for ablation on a rotating uranium target for uranium beam production. The metal ions from volatile compounds technique using volatile compounds has been also tested with ferrocene [Fe(C5H5)2] to produce multicharged Fe ions. We plan to install a third high voltage platform using an EC...
122846748
Giant resonances in {sup 238}U within the quasiparticle random-phase approximation with the Gogny force
Fully consistent axially-symmetric deformed quasiparticle random-phase approximation (QRPA) calculations have been performed, using the same Gogny D1S effective force for both the Hartree-Fock-Bogolyubov mean field and QRPA matrix. New implementation of this approach leads to the applicability of QRPA to heavy deformed nuclei. Giant resonances and low-energy collective states for monopole, dipole, quadrupole, and octupole modes are predicted for the heavy deformed nucleus {sup 238}U and compared with experimental data.
119263588
Spinors and Voros star-product for Group Field Theory: First Contact
In the context of non-commutative geometries, we develop a group Fourier transform for the Lie group SU(2). Our method is based on the Schwinger representation of the Lie algebra su(2) in terms of spinors. It allows us to prove that the non-commutative R space dual to the SU(2) group is in fact of the Moyal-type and endowed with the Voros star-product when expressed in the spinor variables. Finally, from the perspective of quantum gravity, we discuss the application of these new tools to group field theories for spinfoam models and their interpretation as non-commutative field theories with quantum-deformed symmetries.
119210483
Spinors and Twistors in Loop Gravity and Spin Foams
Spinorial tools have recently come back to fashion in loop gravity and spin foams. They provide an elegant tool relating the standard holonomy-flux algebra to the twisted geometry picture of the classical phase space on a fixed graph, and to twistors. In these lectures we provide a brief and technical introduction to the formalism and some of its applications.
119287433
Boundary state stability under spinfoam evolution for the quantum 4-simplex
In the spinfoam framework for quantum gravity, we investigate the conditions to have a physical quantum state for the Barrett–Crane model for the 4D quantum gravity path integral. More precisely, we look at boundary states stable under evolution with respect to the spinfoam kernel. Here, we look at the simplest case of a single 4-simplex boundary and show that the requirement of working with a physical boundary state fixes the width of the semi-classical Gaussian wave-packet for the boundary 3D geometry. This is directly relevant to the graviton propagator calculations done in this framework, since the Gaussian width enters the numerical factors in front of the graviton correlations in the large scale asymptotical limit. Finally, we discuss the application of our computations to the Barrett–Crane model beyond the first order (of a single 4-simplex in the bulk) and to the more recent EPRL-FK spinfoam model.
119459711
Revisiting the simplicity constraints and coherent intertwiners
In the context of loop quantum gravity and spinfoam models, the simplicity constraints are essential in that they allow one to write general relativity as a constrained topological BF theory. In this work, we apply the recently developed U(N) framework for SU(2) intertwiners to the issue of imposing the simplicity constraints to spin network states. More particularly, we focus on solving on individual intertwiners in the 4D Euclidean theory. We review the standard way of solving the simplicity constraints using coherent intertwiners and we explain how these fit within the U(N) framework. Then we show how these constraints can be written as a closed algebra and we propose a set of U(N) coherent states that solves all the simplicity constraints weakly for an arbitrary Immirzi parameter.
119208355
Deformed phase space for 3d loop gravity and hyperbolic discrete geometries
We revisit the loop gravity space phase for 3D Riemannian gravity by algebraically constructing the phase space $T^*\mathrm{SU}(2)\sim\mathrm{ISO}(3)$ as the Heisenberg double of the Lie group $\mathrm{SO}(3)$ provided with the trivial cocyle. Tackling the issue of accounting for a non-vanishing cosmological constraint $\Lambda \ne 0$ in the canonical framework of 3D loop quantum gravity, $\mathrm{SL}(2,\mathbb{C})$ viewed as the Heisenberg double of $\mathrm{SU}(2)$ provided with a non-trivial cocyle is introduced as a phase space. It is a deformation of the flat phase space $\mathrm{ISO}(3)$ and reproduces the latter in a suitable limit. The $\mathrm{SL}(2,\mathbb{C})$ phase space is then used to build a new, deformed LQG phase space associated to graphs. It can be equipped with a set of Gauss constraints and flatness constraints, which form a first class system and Poisson-generate local 3D rotations and deformed translations. We provide a geometrical interpretation for this lattice phase space with constraints in terms of consistently glued hyperbolic triangles, i.e. hyperbolic discrete geometries, thus validating our construction as accounting for a constant curvature $\Lambda<0$. Finally, using ribbon diagrams, we show that our new model is topological.