Theory for nuclear physics and astrophysics in France

Elias Khan

NuPECC, October 9, 2015, Ganil

5IPNO

CEA/DAM

SPhNLUTH

LPC

GANIL

Subatech

CENBG

IPNL

IPHC

Nuclear structure

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Needs for hiring young researchers within the next 5 years (CNRS-CEA-Universities)

The nucleus

• Nucleus = specific manybody system: i) All 4 interactions involved ii) Non elementary constituents iii) Finite size iv) Involved in history of matter

One of the most challenging/richest system to study

• Trend: from [era of models] to [era of theories (DFT, EFT)]

1) Theory for nuclear astrophysics

2) Fundamentals of the nuclear interaction

3) Nuclear structure

3 main axis

Theory for nuclear astrophysics

• Neutron stars: eq. of state, structure (Ganil, LPC, LUTH, IPNL, IPNO, Subatech)

• Supernovae: electron capture, modelisation (Ganil, LPC, LUTH, IPNL, IPNO)

Time line of core collapse SN

Collapse

From T. Janka

Nuclear abundances during the initial phase of collapse

From R. Hix

Nuclear abundances during the neutrino trapping phase

e capture produces neutron rich nuclei, and with fusion of n,p, onegets heavier neutron rich nuclei

F.Gulminelli – LPC CAEN with A.Fantina, J.Margueron, M.Oertel + foreign collaborations(IFIN, LNS, Florianopolis, Coimbra)

Modelling stellar matter for applications to Neutron Stars and Core Collapse Supernova• New phase transitions at zero and

finite temperature• Density functional description of

matter below and above saturation• Unified equation of state for neutron

stars and supernova• Superfluidity in neutron star cooling• Hyperons in dense matter within

relativistic mean field• Connection with nuclear structure and

nuclear reactions• Here: the quenching of N=50

towards the dripline modifies the electron capture rate during supernova core collapse up to a factor ~ 3

Color: distribution of nuclei during core collapse is peaked at magic numbers; full line: limits of experimentally known nuclear mass

Relative modification of the electon capture rate during collapse for two different initial stellar masses, and for different hypothesis on the quenching factors for magicity at N=50 in the unknown neutron rich region defined by the parameter deltaZ.

Fundamentals of the nuclear interaction

• Ab initio, few bodies, EFT (IPHC, IPNO, SPhN)

• Tensor term (CENBG, IPNO, IPNL, SPhN)

Theory program @ IRFU/SPhN

Good overall description 3N forces essential Agreement between different methods Points to limitations of current Chiral-EFT interactions

[Somà, Duguet et al. Phys. Rev. C 061301 (2014)]Two-neutron separation energies

Prediction of the drip line sensitive to 3N

• Development of ab initio methods for nuclear structure ➢ Direct calculation of the A-body system (all nucleons are active)

➢ Only input: 2- and 3-nucleons, e.g. Chiral-EFT, interactions ➢ No intrinsic limitation in mass: current limits set by computational resources➢ Open-shell nuclei = Frontier => Gorkov scheme (made @ Saclay)

• Example: ab initio Gorkov Green’s function calculations

• Short- and long-term future ➢ Extension to doubly open-shells and to additional observables (radii, dipole moments…)➢ Apply Ab initio theories with symmetry restoration recently developed @ Saclay➢ Computational breakthroughs in the treatment of 3N forces➢ Ab-initio driven energy-density functionals➢ Bridging to ab initio description of reactions

Tensor effect in n-rich Ca isotopes

PRC (2013)

Nuclear structure

• Pairing, quarteting, clustering and symmetries: (CENBG, Ganil, IPHC, IPNO)

• Excitation in nuclei and matter (CENBG, DAM, Ganil, IPHC, IPNL, IPNO)

• Exotic nuclei : structure far from stability (all)

• Link with reactions : fission, data oriented, dynamics (DAM, Ganil, IPNO)

• Decays and radioactivity (Ganil, CENBG)

The physics of N=Z nuclei

•Isovector and isoscalar pairing.•Aligned np pairs?•Quarteting?•Enhanced deuteron transfer?•Coulomb displacement energies.•Isospin mixing.

Isacker et al.

EDF Ikeda’s diagramE*

Nature (Letter)

Conclusions

• Variety of methods : EDF (Skyrme, Gogny, Relat.), ab initio, shell-model, IBM, few-body, LD

• Large internationnal impact in each of these fields

• Age : peak at mid-career

• Nucl. theo struct.: increase the collaborations among the group and the methods

• Nucle theo astro: ~ 4 collaborating physicists ; increase the collaboration with exp.

Symmetry-based calculations

Ganil end:Gamow Shell modelReaction for SHE

Thèmes

• Symmetry-based calculations in the shell model and the interacting boson model.

• The physics of N=Z nuclei.• Partial dynamical symmetries in

nuclei and other mesoscopic systems.

• Nuclear-structure calculations for double beta decay.

CENBGShell modelBeyond mean field, correlationsIsospin symmetry

DAMReaction model for dataFission modelisation : SPYCollective vibrations in deformed nucleiMixed SM and MF approaches

IPN

Rigiorous EFT applied to the NN interactionSemi classical methods for neutrons stars and fermi gasesBeyond mean fild and hihger corr in nucle interaction Pairing effects in/and nuclear dynamicsEDM of light nucleiLattice QCD for nucleiNuclear incompressibilityClusters in nuclei

IPHC

CURRENT STATUS EC and b decays crucial in late-stage stellar evolution core-collapse supernova (CCSN), neutron-star cooling, nucleosynthesis, EC SNe

up to now no self-consistent models for EC in SN simulations

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Electron capture (EC) and astrophysics

PROJECT New EC cross-section and rates in finite T self-consistent Skyrme HF + RPA calculations for selected nuclei

PERSPECTIVES New tables of EC rates for an ensemble of nuclei application to SN simulations

Fuller et al., Bruenn (IPM)Langanke et al. (shell model + RPA)

Fantina et al. PRC