Effect of Three Nucleon Forces in p − 3He Scattering

Viviani, M.; Girlanda, L.; Kievsky, A.; Marcucci, L. E.

doi:10.1007/s00601-013-0665-6

Cited by 10 publications

(8 citation statements)

References 35 publications

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“…[24], where the NCSMC was introduced and applied to the description of the unbound 7 He nucleus starting from an accurate N N potential, here we employ this approach for the first time with an Hamiltonian that also includes in addition explicit 3N forces. This is, from an ab initio standpoint, necessary to obtain a truly accurate and quantitative description of the scattering process [28,29]. In particular, we adopt an Hamiltonian based on the chiral N 3 LO N N interaction of Ref.…”

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confidence: 99%

Predictive theory for elastic scattering and recoil of protons fromHe4

2014

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Low-energy cross sections for elastic scattering and recoil of protons from4 He nuclei (also known as α particles) are calculated directly by solving the Schrödinger equation for five nucleons interacting through accurate two-and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe concentrations and depth profiles of either hydrogen or helium. We compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among different data sets and can be used to predict these cross sections when measurements are not available. He proton elastic recoil reactions are the leading means for determining the concentrations and depth profiles of, respectively, helium and hydrogen at the surface of materials or in thin films. Such analyses, known among specialists as (non-)Rutherford backscattering spectroscopy and elastic recoil detection analysis, are very important for characterizing the physical, chemical and electrical behavior of materials, for which hydrogen is one of the most common impurities, and for studying the implantation of helium for applications in, e.g., waveguides or fusion energy research [1,2]. To achieve good resolution e.g. in the case of thick samples, measurements are often performed at energies above the Rutherford threshold where the purely Coulomb elastic scattering paradigm does not hold anymore. In this regime, in which the incident particle energy is on the order of a few MeV per nucleon, nuclear physics becomes the main driver of the scattering process, particularly near low-lying resonances where the cross section can be enhanced by orders of magnitude with respect to the Rutherford rate. Therefore, the availability of accurate reference differential cross sections for a variety of proton/ 4 He incident energies and detection angles are key to the feasibility and quality of these analyses.

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confidence: 99%

Predictive theory for elastic scattering and recoil of protons fromHe4

2014

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“…In particular, aside from a study of the photon-induced disintegration of the 4 He nucleus [40], the present constitutes one of the first applications of chiral N N + 3N interactions to the ab initio calculation of scattering observables in systems with more than three nucleons together with the recent work of Refs. [41] and [42], and the first one for A > 4.…”

Section: Introductionmentioning

confidence: 99%

Ab initiomany-body calculations of nucleon-4He scattering with three-nucleon forces

et al. 2013

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We extend the ab initio no-core shell model/resonating-group method to include three-nucleon (3N ) interactions for the description of nucleon-nucleus collisions. We outline the formalism, give algebraic expressions for the 3N -force integration kernels, and discuss computational aspects of two alternative implementations. The extended theoretical framework is then applied to nucleon-4 He scattering using similarity-renormalization-group (SRG) evolved nucleon-nucleon plus three-nucleon potentials derived from chiral effective field theory. We analyze the convergence properties of the calculated phase shifts and explore their dependence upon the SRG evolution parameter. We include up to six excited states of the 4 He target and find significant effects from the inclusion of the chiral 3N force, e.g., it enhances the spin-orbit splitting between the 3/2 − and 1/2 − resonances and leads to an improved agreement with the phase shifts obtained from an accurate R-matrix analysis of the five-nucleon experimental data. We find remarkably good agreement with measured differential cross sections at various energies, while analyzing powers manifest larger deviations from experiment for certain energies and angles.

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“…Note that the first studies of A = 3 and 4 elastic scattering observables, as cross sections and analyzing powers, with these values for c E and c D have been reported in Ref. [11]. Fig.…”

Section: Electroweak Transition Operatorsmentioning

confidence: 76%