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Gogny-HFB Nuclear Mass Model S. Goriely (ULB), S. Hilaire (CEA-DAM-DIF) et. al. J.-P. Ebran (CEA-DAM-DIF) ECT* 8-12/07/2013
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Outline Gogny-HFB Nuclear Mass Model I. Energy Density Functional II. The Gogny Force III. Results Fock Relativistic Hartree-Fock-Bogoliubov in Axial Symmetry
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allall both Microscopic Mass Model : as good as possible description of all the properties of all nuclei for both ground and excited states Gogny-HFB Mass Model : Motivation Feed Reaction model with Structure ingredients Astrophysical applications : involve nuclei not experimentally accessible predictive Need for predictive approach
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I. Energy Density Functional
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Designed to compute average value of few-body operators Independent particle picture I. Energy Density Functional
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Particle-Hole and Particle-Particle fields involved in HFB-like equation I. Energy Density Functional
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1 particule – 1 hole excitations 2 particules – 2 holes excitations 3 particules – 3 holes excitations 1d5/2 2s1/2 1d3/2 1s1/2 1p3/2 1p1/2 1+[000] 3-[101] 1-[101] 1+[220] 1+[211] 1+[200] 1-[110] 3+[211] 5+[202] 3+[202] Symmetry breaking : take into account additional correlations keeping a single particle picture I. EDF: Symmetry Breaking
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Symmetry breaking : take into account additional correlations keeping a single particle picture I. EDF: Symmetry Breaking
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Restoration of broken symmetries : MR-level Configuration mixing method : GCM I. EDF: Symmetry Restoration
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same finite-range Gogny strategy : parametrize both p-h and p-p channels with the same phenomenological finite-range 2-body interaction II. Gogny Interaction
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D1 D1 : J. Dechargé & D. Gogny, Phys. Rev. C21 1568 (1980) D1S D1S : J.F. Berger, M. Girod & D. Gogny, Comput. Phys. Commun. 63 365 (1991) D1N D1N : F. Chappert, M. Girod & S. Hilaire, Phys. Lett. B668 420 (2008) D1M D1M : S. Goriely, S. Hilaire, M. Girod & S. Péru, Phys. Rev. Lett. 102 242501 (2009). II. Gogny Interaction
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Finite range : Finite range : avoid pathologies “beyond HF” due to unrealistic behavior of 0-range forces at high relative momenta II. Gogny Interaction
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II. Gogny: Two Fitting Philosophies 14 parameters : (W,B,H,M) 1 ; (W,B,H,M) 2 ; t 3 ; x 3 ; ; W LS ; 1 ; 2
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Inversion 4x4 equations system W 1 B 1 H 1 M 1 W 2 B 2 H 2 M 2 Test in Nuclear matter: ( , E/A) sat m*/m K B.E., R c ( 16 O, 90 Zr) Pairing considerations Symmetry energy Initial Data t 3 ; x 3 ; ; W LS ; 1 ; 2 Reject Validation « Theoretical » data at SR-level D1 D1S D1N “Traditional” method involving small set of magic nuclei (!!!) at SR-level II. Gogny: Two Fitting Philosophies
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D1M Make use of the huge data on masses and incorporate a maximum of physics in the functional MR-level Parameters kept constant: 4 (can be included in the fit) 1 =0.7-0.8 ; 2 =1.2 ; x 3 =1 ; =1/3 (0.2-0.5 investigated) Parameters constrained: 3 J ~ 29 - 32 MeV to reproduce at best neutron matter EoS K ~ 230 - 240 MeV as expected from exp. breathing mode data k F kept constant to reproduce charge radii at best (manually adjusted) (a v, J, m *, K, k F )(B 1, H 1, W 2, M 2, t 3 ) Parameters directly fitted to nuclear masses at MR-level: 7 (a v, m *, W 1, M 1, B 2, H 2, W so ) II. Gogny: Two Fitting Philosophies
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D1M Infinite base correction II. Gogny: Two Fitting Philosophies
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D1M 60 Ni II. Gogny: Two Fitting Philosophies
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D1M 120 Sn II. Gogny: Two Fitting Philosophies
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D1M M. Girod and B. Grammaticos, Nucl. Phys. A330 40 (1979) J. Libert, M. Girod and J.-P. Delaroche, Phys. Rev. C60 054301 (1999) GCM + GOA II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force For 1/3 of 2149 exp masses (Audi et al 2003) – N=Z,N=Z±1, N=Z±2 II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K ~ 200/782 exp. charge radii with dynamical correction k F Play on k F to adjust globally II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K ~ 200/782 exp. charge radii with dynamical correction k F Play on k F to adjust globally Nuclear Matter Properties + Landau Parameters (stability, sum rules, G 0 ~ 0; G 0 ’ ~ 0.9-1 (Borzov et al. 1981)) II. Gogny: Two Fitting Philosophies
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244 Pu automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K ~ 200/782 exp. charge radii with dynamical correction k F Play on k F to adjust globally Energy of 2 + levels Nuclear Matter Properties + Landau Parameters (stability, sum rules, G 0 ~ 0; G 0 ’ ~ 0.9-1 (Borzov et al. 1981)) Moment of inertia II. Gogny: Two Fitting Philosophies
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automatic fit on masses Trial force New force Check properties Acceptable rms, J, K New Cstr. Acceptable rms, J, K,prop. D1M II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K New Cstr. Acceptable rms, J, K,prop. New II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K New Cstr. Acceptable rms, J, K,prop. New New quad II. Gogny: Two Fitting Philosophies
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K New Cstr. Acceptable rms, J, K,prop. New New quad II. Gogny: Two Fitting Philosophies
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Quadrupole correction to the binding energy
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automatic fit on masses D1M Trial force New force Check properties Acceptable rms, J, K New Cstr. Acceptable rms, J, K,prop. New New quad II. Gogny: Two Fitting Philosophies
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III. Results: Masses Comparison with 2149 Exp. Masses D1S r.m.s ~ 4.4 MeV E th = E HFB E th = E HFB r.m.s ~ 2.6 MeV E th = E HFB - E th = E HFB - r.m.s ~ 2.9 MeV E th = E HFB - - quad E th = E HFB - - quad
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III. Results: D1N and the Neutron Matter EOS F. Chappert, M. Girod & S. Hilaire, Phys. Lett. B668 (2008) 420.
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III. Results: Masses Comparison with 2149 Exp. Masses D1N r.m.s ~ 2.5 MeV r.m.s ~ 0.95 MeV E th = E HFB E th = E HFB E th = E HFB - E th = E HFB - E th = E HFB - - quad E th = E HFB - - quad
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III. Results: Masses Comparison with 2149 Exp. Masses r.m.s ~ 2.5 MeV = 0.126 MeV r.m.s = 0.798 MeV r.m.s ~ 0.95 MeV
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Results: Masses Comparison with 2149 Exp. Masses = 0.126 MeV r.m.s = 0.798 MeV
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III. Results: Radii Comparison with 707 Exp. Charge Radii r.m.s = 0.031 fm
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III. Results: Pairing Sn
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III. Results: Pairing Sn
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III. Results: Nuclear Matter k F =1.346 fm -1 J=28.6 MeV m*/m=0.746 K inf =225 MeV Pure Neutron Matter
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III. Results: Nuclear Matter k F =1.346 fm -1 J=28.6 MeV m*/m=0.746 K inf =225 MeV
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III. Results: Nuclear Matter
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III. Results: Comparison with other Mass Formula D1M – HFB17D1M – FRDM
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Conclusion & Perspectives First Gogny Mass Model : r.m.s. = 0.798 MeV With Audi et al 2013, r.m.s.(D1M) better and r.m.s.(D1S) gets worse Implementation of exact coulomb exchange and (anti-)pairing Development of generalized Gogny interactions (D2, …) Octupole correlations
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Relativistic Hartree-Fock-Bogoliubov in Axial Symmetry J.-P. Ebran (CEA-DAM-DIF), E. Khan (IPN), D. Peña Arteaga (CEA-DAM-DIF), D. Vretenar (Zagreb University) J.-P. Ebran ECT* 8-12/07/2013
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Why a Relativstic Approach? Kinematics Relevance of covariant approach : not imposed by the need for a relativistic nuclear kinematics, but rather linked to the use of Lorentz symmetry Relativistic potentials : S ~ -400 MeV : Scalar attractive potential V ~ +350 MeV : 4-vector (time-like component) repulsive potential Microscopic structure model = low-energy effective model of QCD Many possible formulations but all not as efficient
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Why a Relativstic Approach? Modification of the vacuum structure in presence of baryonic matter at the origin of the S and V self energies felt by nucleons In medium Chiral Perturbation theory, D. Vretenar et. al.
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Why a Relativstic Approach? QCD sum rules Large scalar and time-like self energies with opposite sign
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Spin-orbit potential emerges naturally with the empirical strenght Time-odd fields = space-like component of 4-potential Empirical pseudospin symmetry in nuclear spectroscopy Saturation mechanism of nuclear matter Why a Relativstic Approach? Figure from C. Fuchs (LNP 641: 119-146, 2004)
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Relativistic mean field models (RMF) treat implicitly Fock terms through fit of model parameters to data Relativistic Hartree-Fock models (RHF): more involved approaches which take explicitly into account the Fock contributions Description of nuclear matter in better agreement with DBHF calculations Tensor contribution to the NN force (pion + ) : better description of shell structure Fully self-consistent beyond mean-field models RHB in axial symmetry D. Vretenar et al Phys.Rep. 409:101- 259,2005 RHFB in spherical symmetry W. Long et al Phys. Rev. C 81, 024308 (2010) N N N N RHFB in axial symmetry J.-P. Ebran et al Phys. Rev. C 83, 064323 (2011) Why Fock Term?
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Hamiltonian Observables Resolution in a deformed harmonic oscillator basis EDF Mean-field approximation : expectation value in the HFB ground state N N N N RHFB equations Minimization N N Lagrangian 8 free parameters RHFBz Model
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Neutron density in the Neon isotopic chain Results
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N=32 Masses SLy4 : M.V. Stoitsov et al, Phys. Rev. C68 (2003) 054312
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Results N=32 static quadrupole deformations
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Results Charge radii
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Conclusion & Perspectives First RHFB model in axial symmetry Encouraging results but too heavy for triaxial calculations or MR-level
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Thank you
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III. Results: Pairing 244 Pu
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III. Results: Pairing 164 Er
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III. Results: Giant Resonances 14.25 MeV GMRGDR 208 Pb 15.85 MeV E exp = 14.17 MeV D. H. Youngblood et al., Phys. Rev. Lett. 82, 691 (1999). E exp = 13.43 MeV B. L. Berman and S. C. Fultz, Rev. Mod. Phys. 47, 713 (1975).
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III. Results: Spectroscopy Excitation energies of the first 2 + for 519 e-e nuclei J.P. Delaroche et al., Phys. Rev. C81 (2010) 014303. S. Hilaire & M. Girod, Eur. Phys. J A33 237(2007)
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III. Results: Nuclear Matter k F =1.346 fm -1 J=28.6 MeV m*/m=0.746 K inf =225 MeV Pure Neutron Matter
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III. Results: Shell Gaps
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Structure properties of ~7000 nuclei + Spectroscopic properties of low energy collective levels for ~1700 even-even nuclei D1S Properties S. Hilaire & M. Girod, Eur. Phys. J A33 237(2007)
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D1S Properties
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Results: Masses Comparison with 2149 Exp. Masses = 0.126 MeV r.m.s = 0.798 MeV
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Quadrupole correction to the binding energy
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Relativistic potentials : S ~ -400 MeV : Scalar attractive potential V ~ +350 MeV : 4-vector (time-like component) repulsive potential Relevance of covariant approach : not imposed by the need of a relativistic nuclear kinematics, but rather linked to the use of Lorentz symmetry Spin-orbit potential emerges naturally with the empirical strenght Time-odd fields = space-like component of 4-potential Empirical pseudospin symmetry in nuclear spectroscopy Saturation mechanism of nuclear matter Why a Relativstic Approach?
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Relativistic mean field models (RMF) treat implicitly Fock terms through fit of model parameters to data Relativistic Hartree-Fock models (RHF): more involved approaches which take explicitly into account the Fock contributions Description of nuclear matter in better agreement with DBHF calculations Tensor contribution to the NN force (pion + ) : better description of shell structure Fully self-consistent beyond mean-field models RHB in axial symmetry D. Vretenar et al Phys.Rep. 409:101- 259,2005 RHFB in spherical symmetry W. Long et al Phys. Rev. C 81, 024308 (2010) N N N N RHFB in axial symmetry J.-P. Ebran et al Phys. Rev. C 83, 064323 (2011) Why a Relativstic Approach?
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S and V potentials characterize the essential properties of nuclear systems : Central Potential : quasi cancellation of potentials Spin-orbit : constructive combination of potentials Spin-orbit Nuclear systems breaking the time reversal symmetry characterized by currents which are accounted for through space-like component of the 4-potentiel : Magnetism
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Why a Relativstic Approach? Pseudo-spin symmetry
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Why a Relativstic Approach? Pseudo-spin symmetry Relativistic interpretation : comes from the fact that |V+S|«|S|≈|V| ( J. Ginoccho PR 414(2005) 165-261 )
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Why a Relativstic Approach? Saturation mechanism of nuclear matter
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Why a Relativstic Approach? p F >> 1 : Scalar density becomes constant Vector density diverge Saturation of nuclear matter
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Why a Relativstic Approach? First contribution to the expansion:
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Why a Relativstic Approach? Figure from C. Fuchs (LNP 641: 119-146, 2004)
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Why Fock terms? Relativistic mean field models (RMF) treat implicitly Fock terms through fit of model parameters to data Relativistic Hartree-Fock models (RHF): more involved approaches which take explicitly into account the Fock contributions RHB in axial symmetry D. Vretenar et al (Phys.Rep. 409:101- 259,2005) RHFB in spherical symmetry W. Long et al (Phys. Rev. C 81:024308, 2010) N N N N RHFB in axial symmetry J.-P. Ebran et al Phys. Rev. C 83, 064323 (2011)
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Why Fock terms? Effective Mass Figure from W. Long et al (Phys.Lett.B 640:150, 2006) Effective mass in symmetric nuclear matter obtained with the PKO1 interaction
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Why Fock terms? Shell Structure Figure from N. van Giai (International Conference Nuclear Structure and Related Topics, Dubna, 2009) Explicit treatment of the Fock term introduction of pion + N tensor coupling N tensor coupling (accounted for in PKA1 interaction) leads to a better description of the shell structure of nuclei: artificial shell closure are cured (N,Z=92 for example)
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Why Fock terms? RPA : Charge exchange excitation Figure from H. Liang et al. (Phys.Rev.Lett. 101:122502, 2008) RHF+RPA model fully self-consistent contrary to RH+RPA model
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Rôle des corrections relativistes dans le mécanisme de saturation Distinction between scalar and vector densities lost : 2) Approches relativistes C. Pourquoi une approche relativiste ? Corrections relativistes i) Non-relativistic limit :
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Rôle des corrections relativistes dans le mécanisme de saturation ii) Corrections relativistes cinématiques : Termes d’ordre dans lesquels Corrections cinématiques peuvent être rajoutées dans n’importe quel potentiel NN non-relativiste Distinction entre densité scalaire et densité vecteur retrouvée, mais brisure de l’auto-cohérence caractérisant l’évaluation de la densité scalaire 2) Approches relativistes C. Pourquoi une approche relativiste ? Corrections relativistes
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Rôle des corrections relativistes dans le mécanisme de saturation Saturation de la matière nucléaire retrouvée à l’échelle du champ moyen!! Mais à une énergie et à un moment de fermi irréalistes 2) Approches relativistes C. Pourquoi une approche relativiste ? Corrections relativistes
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Rôle des corrections relativistes dans le mécanisme de saturation iii) Corrections relativistes dynamiques : corrections générées par le spineur habillé par rapport au spineur libre Saturation de la matière nucléaire plus proche du point empirique 2) Approches relativistes C. Pourquoi une approche relativiste ? Corrections relativistes
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Contenu physique des corrections relativistes dynamiques 2) Approches relativistes C. Pourquoi une approche relativiste ? Corrections relativistes Corrections relativistes dynamiques correspondent à une contribution d’antinucléons. Petit paramètre (~0.1 dans le modèle de Walecka) justifiant développement perturbatif On développe le spineur sur la base des spineurs de Dirac dans le vide
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2) Approches relativistes C. Pourquoi une approche relativiste ? Corrections relativistes Première contribution non-nulle du développement : Contribution interprétée comme une contribution à 3 corps, ne pouvant pas être ajoutée comme correction dans un potentiel NN non-relativiste Contenu physique des corrections relativistes dynamiques
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3) Results A. Ground state observables Two-neutron drip-line Two-neutron separation energy E : S 2n = E tot (Z,N) – E tot (Z,N-2). Gives global information on the Q-value of an hypothetical simultaneous transfer of 2 neutrons in the ground state of (Z,N-2) S 2n < 0 (Z,N) Nucleus can spontaneously and simultaneously emit two neutrons it is beyond the two neutrons drip-line
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3) Results A. Ground state observables Axial deformation For Ne et Mg, PKO2 deformation’s behaviour qualitatively the same than the other interactions PKO2 β systematically weaker than DDME2 and Gogny D1S one
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3) Results A. Ground state observables Charge radii DDME2 closer to experimental data Better agreement between PKO2 and DDME2 for heavier isotopes
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Energy Density Functional
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