Reifarthl R, Altstadt S, Goebell K, Heftrich T, Heil M, Koloczek A, Langer C, Plag R, Pohl M, Sonnabend K, Weigand M, Adachi T, Aksouh F, Al-Khalili J, AlGarawi M, AlGhamdi S, Alkhazov G, Alkhomashi N, Alvarez-Pol H, Alvarez-Rodriguez R, Andreev V, Andrei B, Atar L, Aumann T, Adeichikov V, Bacri C, Bagchi S, Barbieri C, Beceiro S, Beck C, Beinrucker C, Belier G, Bemmerer D, Bendel M, Benlliure J, Benzoni G, Berjillos R, Bertini D, Bertulani C, Bishop S, Blasi N, Bloch T, Blumenfeld Y, Bonaccorso A, Boretzky K, Botvina A, Boudard A, Boutachkov P, Boztosun I, Bracco A, Brambilla S, Briz Monago J, Caamano M, Caesar C, Camera F, Casarejos E, Catford W, Cederkall J, Cederwall B, Chartier M, Chatillon A, Cherciu M, Chulkov L, Coleman-Smith P, Cortina-Gil D, Crespi F, Crespo R, Cresswell J, Csatlos M, Dechery F, Davids B, Davinson T, Derya V, Detistov P, Diaz Fernandez P, DiJuliot D, Dmitry S, Dore D, Duenas J, Dupont E, Egelhof P, Egorova I, Elekes Z, Enders J, Endres J, Ershov S, Ershova O, Fernandez-Dominguez B, Fetisov A, Fiori E, Fomichev A, Fonseca M, Fraile L, Freer M, Friese J, Borge MG, Galaviz Redondo D, Gannon S, Garg U, Gasparic I, Gasques L, Gastineau B, Geissel H, Gernhaeuser R, Ghosh T, Gilbert M, Glorius J, Golubev P, Gorshkov A, Gourishett A, Grigorenko L, Gulyas J, Haiduc M, Hammache F, Harakeh M, Hass M, Heine M, Hennig A, Henriques A, Herzberg R, Holl M, Ignatov A, Ignatyuk A, Ilieva S, Ivanov M, Iwasa N, Jakobsson B, Johansson H, Jonson B, Joshi P, Junghans A, Jurado B, Koerner G, Kalantar N, Kanungo R, Kelic-Heil A, Kezzar K, Khan E, Khanzadeev A, Kiselev O, Kogimtzis M, Koerper D, Kraeckmann S, Kroell T, Kruecken R, Krasznahorkay A, Kratz J, Kresan D, Krings T, Krumbholz A, Krupko S, Kulessa R, Kumar S, Kurz N, Kuzmin E, Labiche M, Langanke K, Lazarus I, Le Bleis T, Lederer C, Lemasson A, Lemmon R, Liberati V, Litvinov Y, Loeher B, Lopez Herraiz J, Muenzenberg G, Machado J, Maev E, Mahata K, Mancusi D, Marganiec J, Martinez Perez M, Marusov V, Mengoni D, Million B, Morcelle V, Moreno O, Movsesyan A, Nacher E, Najafi M, Nakamura T, Naqvi F, Nikolski E, Nilsson T, Nociforo C, Nolan P, Novatsky B, Nyman G, Ornelas A, Palit R, Pandit S, Panin V, Paradela C, Parkar V, Paschalis S, Pawlowski P, Perea A, Pereira J, Petrache C, Petri M, Pickstone S, Pietralla N, Pietri S, Pivovarov Y, Potlog P, Prokofiev A, Rastrepina G, Rauscher T, Ribeiro G, Ricciardi M, Richter A, Rigollet C, Riisager K, Rios A, Ritter C, Frutos TR, Rodriguez Vignote J, Roeder M, Romig C, Rossi D, Roussel-Chomaz P, Rout P, Roy S, Soederstroem P, Sarkar MS, Sakuta S, Salsac M, Sampson J, del Rio Saez JS, Sanchez Rosado J, Sanjari S, Sarriguren P, Sauerwein A, Savran D, Scheidenberger C, Scheit H, Schmidt S, Schmitt C, Schnorrenberger L, Schrock P, Schwengner R, Seddon D, Sherrill B, Shrivastava A, Sidorchuk S, Silva J, Simon H, Simpson E, Singh P, Slobodan D, Sohler D, Spieker M, Stach D, Stan E, Stanoiu M, Stepantsov S, Stevenson P, Strieder F, Stuhl L, Suda T, Suemmerer K, Streicher B, Taieb J, Takechi M, Tanihata I, Taylor J, Tengblad O, Ter-Akopian G, Terashima S, Teubig P, Thies R, Thoennessen M, Thomas T, Thornhill J, Thungstrom G, Timar J, Togano Y, Tomohiro U, Tornyi T, Tostevin J, Townsley C, Trautmann W, Trivedi T, Typel S, Uberseder E, Udias J, Uesaka T, Uvarov L, Vajta Z, Velho P, Vikhrov V, Volknandt M, Volkov V, von Neumann-Cose P, von Schmid M, Wagner A, Wamers F, Weick H, Wells D, Westerberg L, Wieland O, Wiescher M, Wimmer C, Wimmer K, Winfield JS, Winkel M, Woods P, Wyss R, Yakorev D, Yavor M, Cardona JZ, Zartova I, Zerguerras T, Zgura I, Zhdanov A, Zhukov M, Zieblinski M, Zilges A, Zuber K (2016) Nuclear astrophysics with radioactive ions at FAIR, Nuclear Physics in Astrophysics VI (NPA6). Journal of Physics: Conference Series 665 (1) IOP Publishing
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, ²-decay chains. These nuclei are attributed to the p and rp process.
For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections.
The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
Ab-initio predictions of nuclei with masses up to A
We present results from a new ab initio method that uses the self-consistent Gorkov-Green's function theory to address truly open-shell systems. The formalism has been recently worked out up to second order and is implemented here in nuclei on the basis of realistic nuclear forces. Benchmark calculations indicate that the method is in agreement with other ab initio approaches in doubly closed shell 40Ca and 48Ca. We find good convergence of the results with respect to the basis size in 44Ca and 74Ni and discuss quantities of experimental interest including ground-state energies, pairing gaps, and particle addition and removal spectroscopy. These results demonstrate that the Gorkov method is a valid alternative to multireference approaches for tackling degenerate or near-degenerate quantum systems. In particular, it increases the number of mid-mass nuclei accessible in an ab initio fashion from a few tens to a few hundred. © 2013 American Physical Society.
Middleton DG, Annand JRM, Barbieri C, Barneo P, Bartsch P, Baumann D, Bermuth J, Bosnar D, Blok HP, Boehm R, Ding M, Distler MO, Elsner D, Friedrich J, Giusti C, Glazier DI, Grabmayr P, Groezinger S, Hehl T, Heim J, Hesselink WHA, Jans E, Klein F, Kohl M, Lapikas L, MacGregor IJD, Martin I, McGeorge JC, Merkel H, Merle P, Moschini F, Mueller U, Pospischil T, Rosner G, Schmieden H, Seimetz M, Suele A, de Vries H, Walcher T, Watts DP, Weis M, Zihlmann B (2006) First measurements of the O-16(e, e ' pn)N-14 reaction (vol 29, pg 261, 2006), EUROPEAN PHYSICAL JOURNAL A 30 (2) pp. 469-469 SPRINGER
An ab initio calculation scheme for finite nuclei based on self-consistent Green's functions in the Gorkov formalism is developed. It aims at describing properties of doubly magic and semimagic nuclei employing state-of-the-art microscopic nuclear interactions and explicitly treating pairing correlations through the breaking of U(1) symmetry associated with particle number conservation. The present paper introduces the formalism necessary to undertake applications at (self-consistent) second order using two-nucleon interactions in a detailed and self-contained fashion. First applications of such a scheme will be reported soon in a forthcoming publication. Future works will extend the present scheme to include three-nucleon interactions and implement more advanced truncation schemes.
We extend the self-consistent Green's functions formalism to take into account three-body interactions. We analyze the perturbative expansion in terms of Feynman diagrams and define effective one- and two-body interactions, which allows for a substantial reduction of the number of diagrams. The procedure can be taken as a generalization of the normal ordering of the Hamiltonian to fully correlated density matrices. We give examples up to third order in perturbation theory. To define nonperturbative approximations, we extend the equation of motion method in the presence of three-body interactions. We propose schemes that can provide nonperturbative resummation of three-body interactions. We also discuss two different extensions of the Koltun sum rule to compute the ground state of a many-body system.
This contribution reviews a calculation of two-step rescattering events in (e,e'p) reactions. A semiclassical approach is employed for different kinematics, involving both medium and large missing energies. The effects of nuclear transparency and Pauli blocking are also included. The results are of interest for experiments aimed to study short-range correlations in the spectral distribution and suggest that the effects of rescattering can be strongly reduced in parallel kinematics. The comparison with the experimental data seem to confirm that sensible measurements could be achievable with a careful choice of the kinematics. However, contributions to final state interactions beyond the ones considered here become relevant for heavy nuclei. For transverse kinematics, rescattering induce large shifts of the spectral strength that can lead to a total experimental yield much larger than the direct signal. © Società Italiana di Fisica / Springer-Verlag 2005.
Background: The possibility that an unconventional depletion (referred to as a ?bubble?) occurs in the center of the charge density distribution of certain nuclei due to a purely quantum mechanical effect has attracted theoretical and experimental attention in recent years. Based on a mean-field rationale, a correlation between the occurrence of such a semibubble and an anomalously weak splitting between low angular-momentum spin-orbit partners has been further conjectured. Energy density functional and valence-space shell model calculations have been performed to identify and characterize the best candidates, among which 34 Si appears as a particularly interesting case. While the experimental determination of the charge density distribution of the unstable 34 Si is currently out of reach, ( d , p ) experiments on this nucleus have been performed recently to test the correlation between the presence of a bubble and an anomalously weak 1 / 2 ? ? 3 / 2 ? splitting in the spectrum of 35 Si as compared to 37 S .Purpose: We study the potential bubble structure of 34 Si on the basis of the state-of-the-art ab initio self-consistent Green's function many-body method. Methods: We perform the first ab initio calculations of 34 Si and 36 S . In addition to binding energies, the first observables of interest are the charge density distribution and the charge root-mean-square radius for which experimental data exist in 36 S . The next observable of interest is the low-lying spectroscopy of 35 Si and 37 S obtained from ( d , p ) experiments along with the spectroscopy of 33 Al and 35 P obtained from knock-out experiments. The interpretation in terms of the evolution of the underlying shell structure is also provided. The study is repeated using several chiral effective field theory Hamiltonians as a way to test the robustness of the results with respect to input internucleon interactions. The convergence of the results with respect to the truncation of the many-body expansion, i.e., with respect to the many-body correlations included in the calculation, is studied in detail. We eventually compare our predictions to state-of-the-art multireference energy density functional and shell model calculations. Results: The prediction regarding the (non)existence of the bubble structure in 34 Si varies significantly with the nuclear Hamiltonian used. However, demanding that the experimental charge density distribution and the root-mean-square radius of 36 S be well reproduced, a
We perform ab initio self-consistent Green?s function calculations of the closed shell nuclei 4He, 16O and
40Ca, based on two-nucleon potentials derived from Lattice QCD simulations, in the flavor SU(3) limit and at
the pseudo-scalar meson mass of 469 MeV/c
. The nucleon-nucleon interaction is obtained using the HAL QCD
method and its short-distance repulsion is treated by means of ladder resummations outside the model space.
Our results show that this approach diagonalises ultraviolet degrees of freedom correctly. Therefore, ground
state energies can be obtained from infrared extrapolations even for the relatively hard potentials of HAL QCD.
Comparing to previous Brueckner Hartree-Fock calculations, the total binding energies are sensibly improved
by the full account of many-body correlations. The results suggest an interesting possible behaviour in which
nuclei are unbound at very large pion masses and islands of stability appear at first around the traditional doublymagic
numbers when the pion mass is lowered toward its physical value. The calculated one-nucleon spectral
distributions are qualitatively close to those of real nuclei even for the pseudo-scalar meson mass considered
Self-consistent Green?s function theory has recently been extended to the basic formalism needed
to account for three-body interactions [A. Carbone, A. Cipollone, C. Barbieri, A. Rios, and A. Polls, Phys. Rev.
C 88, 054326 (2013)]. The contribution of three-nucleon forces has then been included in ab initio calculations
on nuclear matter and isotopic chains of finite nuclei.
ractical applications across post Hartree-Fock methods have mostly considered the contribution of
three-nucleon interactions in an effective way, as averaged two-nucleon forces. We derive the working equations
for all possible two- and three-nucleon terms that enter the expansion of the self-energy, including interactionirreducible
(i.e. not averaged) three-nucleon diagrams.
We employ the algebraic diagrammatic construction up to third order as the organization scheme for
generating a non perturbative self-energy, in which ring (particle-hole) and ladder (particle-particle) diagrams are
resummed to all orders.
We derive expressions of the static and dynamic self-energy up to third order, by taking into account
also the set of diagrams required when the skeleton expansion of the single-particle propagator is not assumed. A
hierarchy of importance among different diagrams is revealed, and a particular emphasis is given to a third-order
diagram (see Fig. 2c) which is expected to play a significant role among those featuring an interaction-irreducible
A consistent formalism to resum at infinite order correlations induced by three-nucleon forces in the
self-consistent Green?s function theory is now available, and ready to be implemented in the many-body solvers.
Work is in progress to include the first interaction-irreducible three-nucleon diagram in calculations of closed-shell
Leistenschneider E, Reiter M, Ayet San Andrés S, Kootte B, Holt J, Navrátil P, Babcock C, Barbieri Carlo, Barquest B, Bergmann J, Bollig J, Brunner T, Dunling E, Finlay A, Geissel H, Graham L, Greiner F, Hergert H, Hornung C, Jesch C, Klawitter R, Lan Y, Lascar D, Leach K, Lippert W, McKay J, Paul S, Schwenk A, Short D, Simonis J, Somà V, Steinbrügge R, Stroberg S, Thompson R, Wieser M, Will C, Yavor M, Andreoiu C, Dickel T, Dillmann I, Gwinner G, Plaß W, Scheidenberger C, Kwiatkowski A, Dilling J (2018) Dawning of the N=32 Shell Closure Seen through Precision Mass Measurements of Neutron-Rich Titanium Isotopes, Physical Review Letters 120 (6) 062503
American Physical Society
A precision mass investigation of the neutron-rich titanium isotopes
was performed at TRIUMF?s Ion Trap for Atomic and Nuclear science (TITAN). The range of the measurements covers the
shell closure, and the overall uncertainties of the
mass values were significantly reduced. Our results conclusively establish the existence of the weak shell effect at
, narrowing down the abrupt onset of this shell closure. Our data were compared with state-of-the-art ab initio shell model calculations which, despite very successfully describing where the
shell gap is strong, overpredict its strength and extent in titanium and heavier isotones. These measurements also represent the first scientific results of TITAN using the newly commissioned multiple-reflection time-of-flight mass spectrometer, substantiated by independent measurements from TITAN?s Penning trap mass spectrometer.
Atar L, Paschalis S, Barbieri Carlo, Bertulani C, Díaz Fernández P, Hollington M, Najafi M, Panin V, Alvarez-Pol H, Aumann T, Avdeichikov V, Beceiro-Novo S, Bemmerer D, Benlliure J, Boillos J, Boretzky K, Borge M, Caamaño M, Caesar C, Casarejos E, Catford Wilton, Cederkall J, Chartier M, Chulkov L, Cortina-Gil D, Cravo E, Crespo R, Dillmann I, Elekes Z, Enders J, Ershova O, Estrade A, Farinon F, Fraile L, Freer M, Galaviz Redondo D, Geissel H, Gernhäuser R, Golubev P, Göbel K, Hagdahl J, Heftrich T, Heil M, Heine M, Heinz A, Henriques A, Hufnagel A, Ignatov A, Johansson H, Jonson B, Kahlbow J, Kalantar-Nayestanaki N, Kanungo R, Kelic-Heil A, Knyazev A, Kröll T, Kurz N, Labiche M, Langer C, Le Bleis T, Lemmon R, Lindberg S, Machado J, Marganiec-GaB?zka J, Movsesyan A, Nacher E, Nikolskii E, Nilsson T, Nociforo C, Perea A, Petri M, Pietri S, Plag R, Reifarth R, Ribeiro G, Rigollet C, Rossi D, Röder M, Savran D, Scheit H, Simon H, Sorlin O, Syndikus I, Taylor J, Tengblad O, Thies R, Togano Y, Vandebrouck M, Velho P, Volkov V, Wagner A, Wamers F, Weick H, Wheldon C, Wilson G, Winfield J, Woods P, Yakorev D, Zhukov M, Zilges A, Zuber K (2018) Quasifree ( p , 2p ) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength, Physical Review Letters 120 (5) 052501
American Physical Society
Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic
study of the structure of stable and exotic oxygen isotopes at the R3B=LAND setup with incident beam
energies in the range of 300?450 MeV=u. The oxygen isotopic chain offers a large variation of separation
energies that allows for a quantitative understanding of single-particle strength with changing isospin
asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy onenucleon
removal reactions. Inclusive cross sections for quasifree knockout reactions of the type
AOðp; 2pÞA?1N have been determined and compared to calculations based on the eikonal reaction theory.
The reduction factors for the single-particle strength with respect to the independent-particle model were
obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant
dependence on proton-neutron asymmetry.
We present results for charge form factors, the point-proton, charge, and single-nucleon momentum distributions of
obtained within the self-consistent Green's function approach. The removal of the center-of-mass contribution for both nuclei has been performed by using a metropolis Monte Carlo algorithm in which the center-of-mass coordinate can be exactly subtracted from the optimal reference state wave function generated during the self-consistent Green's function calculations. The spectral functions of the same two nuclei have been used to compute inclusive electron-nucleus cross sections. The formalism adopted is based on the factorization of the spectral function and the nuclear transition matrix elements. This allows us to provide an accurate description of nuclear dynamics and to account for relativistic effects in the interaction vertex. When final-state interactions for the struck particle are accounted for, we find nice agreement between the data and the theory for the inclusive electron-
cross section. The results lay the foundations for future applications of the self-consistent Green's function method, in both closed and open shell nuclei, to neutrino data analysis.
The factorization scheme, based on the impulse approximation and the spectral function formalism, has been recently generalized to allow the description of electromagnetic nuclear interactions driven by two-nucleon currents. We have extended this framework to the case of weakly charged and neutral currents, and carried out calculations of the double-differential neutrino-carbon and neutrino-oxygen cross sections using two different models of the target spectral functions. The results, showing a moderate dependence on the input spectral function, confirm that our approach provides a consistent treatment of all reaction mechanisms contributing to the signals detected by accelerator-based neutrino experiments.
Background: Microscopic calculations of the electromagnetic response of light and medium-mass nuclei are now feasible thanks to the availability of realistic nuclear interactions with accurate saturation and spectroscopic properties, and the development of large-scale computing methods for many-body physics.
Purpose: To compute isovector dipole electromagnetic (E1) response and related quantities, i.e., integrated dipole cross section and polarizability, and compare with data from photoabsorption and Coulomb excitation experiments. To investigate the evolution pattern of the E1 response towards the neutron drip line with calculations of neutron-rich nuclei within a given isotopic chain.
Methods: The single-particle propagator is obtained by solving the Dyson equation, where the self-energy includes correlations nonperturbatively through the algebraic diagrammatic construction (ADC) method. The particle-hole (ph) polarization propagator is treated in the dressed random phase approximation (DRPA), based on an effective correlated propagator that includes some 2p2h effects but keeps the same computation scaling as the standard Hartree-Fock propagator.
Results: The E1 responses for 14,16,22,24O, 36,40,48,52,54,70Ca, and 68Ni have been computed: The presence of a soft dipole mode of excitation for neutron-rich nuclei is found, and there is a fair reproduction of the low-energy part of the experimental excitation spectrum. This is reflected in a good agreement with the empirical dipole polarizability values. The impact of different approximations to the correlated propagator used as input in the E1 response calculation is assessed.
Conclusion: For a realistic interaction that accurately reproduces masses and radii, an effective propagator of the mean-field type computed by the self-consistent Green's function provides a good description of the empirical E1 response, especially in the low-energy part of the excitation spectrum and around the giant dipole resonance. The high-energy part of the spectrum improves and displays an enhancement of the strength when quasiparticle fragmentation is added to the reference propagator. However, this fragmentation (without a proper restoration of dynamical self-consistency) spoils the predictions of the energy centroid of the giant dipole resonance.