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1.
Phys Rev Lett ; 121(9): 099901, 2018 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-30230855

RESUMO

This corrects the article DOI: 10.1103/PhysRevLett.117.182502.

2.
Phys Rev Lett ; 117(18): 182502, 2016 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-27835011

RESUMO

We utilize various ab initio approaches to search for a low-lying resonance in the four-neutron (4n) system using the JISP16 realistic NN interaction. Our most accurate prediction is obtained using a J-matrix extension of the no-core shell model and suggests a 4n resonant state at an energy near E_{r}=0.8 MeV with a width of approximately Γ=1.4 MeV.

3.
Phys Rev Lett ; 111(25): 252501, 2013 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-24483740

RESUMO

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.


Assuntos
Berílio/química , Hélio/química , Lítio/química , Modelos Químicos , Radioisótopos/química , Teoria Quântica
4.
Phys Rev Lett ; 106(6): 061603, 2011 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-21405457

RESUMO

Recent experiments with heavy ions and planned experiments with ultraintense lasers require nonperturbative solutions to quantum field theory for predicting and interpreting the results. To propel this theoretical direction, we solve the nonperturbative problem of an electron in a strong transverse confining potential using Hamiltonian light-front quantum field theory. We evaluate both the invariant mass spectra and the anomalous magnetic moment of the lowest state for this two-scale system. The weak external field limit of the anomalous magnetic moment agrees with the result of QED perturbation theory within the anticipated accuracy.


Assuntos
Elétrons , Modelos Teóricos , Magnetismo , Teoria Quântica
5.
Phys Rev Lett ; 106(20): 202502, 2011 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-21668224

RESUMO

We report the microscopic origins of the anomalously suppressed beta decay of ¹4C to ¹4N using the ab initio no-core shell model with the Hamiltonian from the chiral effective field theory including three-nucleon force terms. The three-nucleon force induces unexpectedly large cancellations within the p shell between contributions to beta decay, which reduce the traditionally large contributions from the nucleon-nucleon interactions by an order of magnitude, leading to the long lifetime of ¹4C.

6.
Phys Rev Lett ; 99(4): 042501, 2007 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-17678354

RESUMO

Properties of finite nuclei are evaluated with two-nucleon (NN) and three-nucleon (NNN) interactions derived within chiral effective field theory. The nuclear Hamiltonian is fixed by properties of the A=2 system, except for two low-energy constants (LECs) that parametrize the short range NNN interaction, which we constrain with the A=3 binding energies. We investigate the sensitivity of 4He, 6Li, 10,11B, and 12,13C properties to the variation of the constrained LECs. We identify observables that are sensitive to this variation and find preferred values that give the best overall description. We demonstrate that the NNN interaction terms significantly improve the binding energies and spectra of mid-p-shell nuclei not just with the preferred choice of the LECs but even within a wide range of the constrained LECs. We find that a very high quality description of these nuclei requires further improvements to the chiral Hamiltonian.

7.
Phys Rev Lett ; 91(1): 012502, 2003 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-12906537

RESUMO

We investigate cross sections for neutrino-12C exclusive scattering and for muon capture on 12C using wave functions obtained in the ab initio no-core shell model. In our parameter-free calculations with basis spaces up to the 6 variant Planck's over 2pi Omega we show that realistic nucleon-nucleon interactions, like, e.g., the CD-Bonn, underpredict the experimental cross sections by more than a factor of 2. By including a realistic three-body interaction, Tucson-Melbourne TM'(99), the cross sections are enhanced significantly and a much better agreement with experiment is achieved. At the same time, the TM'(99) interaction improves the calculated level ordering in 12C. The comparison between the CD-Bonn and the three-body calculations provides strong confirmation for the need to include a realistic three-body interaction to account for the spin-orbit strength in p-shell nuclei.

8.
Phys Rev Lett ; 84(25): 5728-31, 2000 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-10991040

RESUMO

We obtain properties of 12C in the ab initio no-core nuclear shell model. The effective Hamiltonians are derived microscopically from the realistic CD Bonn and the Argonne V8' nucleon-nucleon (NN) potentials as a function of the finite harmonic oscillator basis space. Binding energies, excitation spectra, and electromagnetic properties are presented for model spaces up to 5Planck's over 2piOmega. The favorable comparison with available data is a consequence of the underlying NN interaction rather than a phenomenological fit.

9.
Phys Rev Lett ; 87(17): 172502, 2001 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-11690268

RESUMO

We apply the ab initio no-core nuclear shell model to solve the six-nucleon systems, (6)Li and (6)He, interacting by realistic nucleon-nucleon ( NN) potentials. In particular, we present the first results for A = 6 with the nonlocal CD-Bonn NN potential. The resulting (6)Li binding energy -29.3(6) MeV and the excitation spectra improve the agreement between the theory and experiment compared to results with local NN potentials, but the need for the inclusion of a real three-body interaction and/or further improvement of the NN forces remains. We predict properties of the (6)He dipole modes, a subject of current controversy.

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