Nuclear forces can be systematically derived using effective chiral Lagrangians consistent with the symmetries of QCD. I review the status of the calculations for two- and three-nucleon forces and their applications in few-nucleon systems. I also address issues like the quark mass dependence of the nuclear forces and resonance saturation for four-nucleon operators.

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Modern theory of nuclear forces

We review how nuclear forces emerge from low-energy QCD via chiral effective field theory. The presentation is accessible to the non-specialist. At the same time, we also provide considerable detailed information (mostly in appendices) for the benefit of researchers who wish to start working in this field.

Chiral effective field theory and nuclear forces

▪ Abstract Accurate quantum Monte Carlo calculations of ground states and low-lying excited states of light p-shell nuclei are now possible for realistic nuclear Hamiltonians that fit nucleon-nucleon scattering data. Results for more than 30 different (Jπ;T) states, plus isobaric analogs, in A ≤ 8 nuclei have been obtained with an excellent reproduction of the experimental energy spectrum. These microscopic calculations show that nuclear structure, including both single-particle and clustering aspects, can be explained starting from elementary two- and three-nucleon interactions. Various density and momentum distributions, electromagnetic form factors, and spectroscopic factors have also been computed, as well as electroweak capture reactions of astrophysical interest.

Quantum Monte Carlo Calculations of Light Nuclei

The nuclear physics landscape has been redesigned as a sequence of effective field theories (EFTs) connected to the Standard Model through symmetries and lattice simulations of Quantum Chromodynamics (QCD). EFTs in this sequence are expansions around different low-energy limits of QCD, each with its own characteristics, scales, and ranges of applicability regarding energy and number of nucleons. We review each of the three main nuclear EFTs---Chiral, Pionless, Halo/Cluster---highlighting their similarities, differences, and connections. In doing so, we survey the structural properties and reactions of nuclei that have been derived from the ab initio solution of the few- and many-body problem built upon EFT input.

Nuclear effective field theory: status and perspectives

We have derived a two-pion-exchange three-body force and calculated its contribution to the trinucleon ground state. The hyperspherical harmonic method has been used. Coulomb and the three-body forces have been treated nonperturbatively. Results show sensitivity to the short range part of the force. A comparative study is made with other forms of three-body forces found in the literature.NUCLEAR STRUCTURE Trinucleon systems, three-body force.

Two-pion-exchange three-nucleon force and the /sup 3/H and /sup 3/He nuclei

The accuracy of the uncoupled adiabatic approximation is investigated for bound trinucleon systems. The quality of this approximation is related to the strength of the repulsive core of the nuclear potential.

Uncoupled adiabatic approximation for the hyperspherical harmonic approach

The hyperspherical harmonic method has been used to calculate the effect of two-pion exchange three-body force (Fujita-Miyazawa type) on trinucleon systems, with the $N\ensuremath{-}N$ Afnan- Tang S3 potential. The Coulomb force and three-body force have been taken into account nonperturbatively. Simplification in the numerical calculation has been achieved through the use of an adiabatic approximation in order to decouple the system of differential equations. Binding energy, charge form factor, and pointlike proton density of both $^{3}\mathrm{H}$ and $^{3}\mathrm{He}$ have been calculated for various values of the cutoff parameter in the three-body force. Results indicate that the inclusion of the three-body force improves agreement with experiment. An interesting feature is the possible appearance of nodes near origin in the hyper-radial wave function.NUCLEAR STRUCTURE Trinucleon systems; three-body force; bound states of $^{3}\mathrm{H}$ and $^{3}\mathrm{He}$ using hyperspherical harmonic method; adiabatic approximation; charge form factors.

H.T. Coelho

Papers

Two-pion-exchange three-nucleon force and the /sup 3/H and /sup 3/He nuclei

Uncoupled adiabatic approximation for the hyperspherical harmonic approach

Contribution of three-body force to the trinucleon problem by an essentially exact calculation

Adiabatic approximation in few-body molecular and nuclear systems.

Effect of two-pion-exchange three-nucleon forces on trinucleon bound systems