| 1. |
- Rotureau, Jimmy, 1976, et al.
(författare)
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Effective Field Theory and the Gamow Shell Model: The 6He Halo Nucleus
- 2013
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Ingår i: Few-Body Systems. - : Springer Science and Business Media LLC. - 1432-5411 .- 0177-7963. ; 54:5-6, s. 725-735
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Tidskriftsartikel (refereegranskat)abstract
- We combine halo/cluster effective field theory (H/CEFT) and the Gamow shell model (GSM) to describe the 0+ ground state of 6He as a three-body halo system. We use two-body interactions for the neutron-alpha particle and two-neutron pairs obtained from H/CEFT at leading order, with parameters determined from scattering in the p3/2 and s0 channels, respectively. The three-body dynamics of the system is solved using the GSM formalism, where the continuum states are incorporated in the shell model valence space. We find that in the absence of three-body forces the system collapses, since the binding energy of the ground state diverges as cutoffs are increased. We show that addition at leading order of a three-body force with a single parameter is sufficient for proper renormalization and to fix the binding energy to its experimental value.
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| 2. |
- Rotureau, Jimmy, 1976, et al.
(författare)
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Two and three nucleons in a trap, and the continuum limit
- 2012
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 85:3
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Tidskriftsartikel (refereegranskat)abstract
- We describe systems of two and three nucleons trapped in a harmonic-oscillator potential with interactions from the pionless effective field theory up to next-to-leading order (NLO). We construct the two-nucleon interaction using two-nucleon scattering information. We calculate the trapped levels in the three-nucleon system with isospin T = 1/2 and determine the three-nucleon force needed for stability of the triton. We extract neutron-deuteron phase shifts, and show that the quartet scattering length is in good agreement with experimental data.
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| 3. |
- RYBERG, EMIL, 1987, et al.
(författare)
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Finite-size effects in heavy halo nuclei from effective field theory
- 2020
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 56:1
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Tidskriftsartikel (refereegranskat)abstract
- Halo/Cluster Effective Field Theory describes halo/cluster nuclei in an expansion in the small ratio of the size of the core(s) to the size of the system. Even in the point-particle limit, neutron-halo nuclei have a finite charge radius, because their center of mass does not coincide with their center of charge. This point-particle contribution decreases as 1 / Ac, where Ac is the mass number of the core, and diminishes in importance compared to other effects, e.g., the size of the core to which the neutrons are bound. Here we propose that for heavy cores the EFT expansion should account for the small factors of 1 / Ac. As a specific example, we discuss the implications of this organizational scheme for the inclusion of finite-size effects in expressions for the charge radii of halo nuclei. We show in particular that a short-range operator could be the dominant effect in the charge radius of one-neutron halos bound by a P-wave interaction. The point-particle contribution remains the leading piece of the charge radius for one-proton halos, and so Halo EFT has more predictive power in that case.
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| 4. |
- Yang, Chieh-Jen, 1977, et al.
(författare)
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The importance of few-nucleon forces in chiral effective field theory
- 2023
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Ingår i: European Physical Journal A. - 1434-601X .- 1434-6001. ; 59:10
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Tidskriftsartikel (refereegranskat)abstract
- We study the importance of few-nucleon forces in chiral effective field theory for describing many-nucleon systems. A combinatorial argument suggests that three-nucleon forces-which are conventionally regarded as next-to-next-to-leading order-should accompany the two-nucleon force already at leading order (LO) starting with mass number A≃ 10–20. We find that this promotion enables the first realistic description of the 16 O ground state based on a renormalization-group-invariant LO interaction. We also performed coupled-cluster calculations of the equation of state for symmetric nuclear matter and our results indicate that LO four-nucleon forces could play a crucial role for describing heavy-mass nuclei. The enhancement mechanism we found is very general and could be important also in other many-body problems.
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