Momentum-space calculations for three-nucleon scattering including a three-nucleon force

The formalism to include a three-nucleon force into three-nucleon continuum calculations is presented. First numerical results, obtained in momentum space, are shown. The two- and three-nucleon forces have been restricted to act only in the¹ S ₀ and³ S ₁-³ D ₁ partial-wave states. As two-nucleon interaction the Bonn-B potential and as three-nucleon interaction the Tucson-Melbourne two-pion exchange model has been used.     

Adiabatic calculation of the three-nucleon force

A preliminary estimate of the three-nucleon force within the adiabatic framework has already been done. In this work we try to improve the first calculation by using relativistic kinematics for the pion and including theP 11 absorption channel, as well as theP 33 and the less importantS 13,S 11,P 13,P 31 channels, in theN interaction.Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia. May 27–June 1, 1985.     

The three-nucleon system

A brief review is given of the recent progress made in the study of the three-nucleon problem with local interactions. In particular, it is pointed out that the presence of meson exchange currents can contribute significantly to the³He charge form factor at high momentum transfer.Invited talk at the symposium Theory of lightest nuclei, Liblice, Czechoslovakia, May 1974.     

Relativity in the three-nucleon system

A Poincaré-invariant formulation of the three-body system is used. The two-body force embedded in the three-particle Hilbert space is generated out of the high-precision NN forces by solving a nonlinear equation. The solution of the relativistic 3N Faddeev equation for ³H reveals less binding energy than for the nonrelativistic one. The effect of the Wigner spin rotation on the binding energy is very small.     

Efficient emulator for solving three-nucleon continuum Faddeev equations with chiral three-nucleon force comprising any number of contact terms

The European Physical Journal A - We investigate the structure of the meson Regge trajectories based on the quadratic form of the spinless Salpeter-type equation. It is found that the forms of the...     

The Tucson-Melbourne three-nucleon force in the automatized partial-wave decomposition

A recently developed procedure for a partial-wave decomposition of a three-nucleon force is applied to the p pi -p pi , p pi -r rho and r rho -r rho components of the Tucson-Melbourne three-nucleon potential. The resulting matrix elements for the p pi -p pi and p pi -r rho components are compared with the values obtained using the standard approach to the partial-wave decomposition, in which the p pi -r rho expressions for the matrix elements are also derived and presented. Several numerical tests and results for the triton binding energy and the correlation function prove the reliability and efficiency of the new method.     

Three-nucleon forces studied by nucleon-deuteron scattering

Recent experimental progress of the three-nucleon force study is shown placing an emphasis on the nucleon-deuteron elastic scattering at intermediate energies. Correspondence: H. Sakai, Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan     

Off-shell effects in the three-nucleon system

The triton binding energy and the neutron-deuteron doublet scattering length have been studied with phase-equivalent rank-2 separable potentials in S-waves. The potentials have been constructed from the phase shifts using the solution of the inverse scattering problem. Large off-shell effects are connected with the appearance of additional nodes in the deuteron or the low-energy singlet wave functions.     

Nucleon-nucleon interaction in the three-nucleon system

The three-nucleon system is reconsidered. The Faddeev equations are given leading to a set of integral equations. Solving these integral equations, suitable forms are considered for the nucleon-nucleon interaction. In the bound state of three-nucleon system, the form of the nuclear forces from the nucleon-nucleon interaction is important. In the present calculations, we consider the nuclear forces resulting from the nucleon-nucleon interaction by the exchange of a scalar meson, a pseudoscalar meson, and a massless vector meson. With this different meson exchange nucleon-nucleon interaction, the binding energy of the three-nucleon system is calculated by solving the Faddeev integral equations giving a value of 8.452 MeV.     

The three-nucleon system near the N-d threshold

The three-nucleon system is studied at energies a few hundred keV above the N-d threshold. Measurements of the tensor analyzing powers T₂₀ and T₂₁ for p-d elastic scattering at E_c.m. = 432 keV are presented together with the corresponding theoretical predictions. The calculations are extended to very low energies since they are useful for extracting the p-d scattering lengths from the experimental data. The interaction considered here is the Argonne V18 potential plus the Urbana three-nucleon potential. The calculation of the asymptotic D- to S-state ratio for ³H and ³He, for which recent experimental results are available, is also presented.     

Binary scattering and breakup in the three-nucleon system

We present the further development of the three-particle formalism for differential Faddeev equations. The asymptotic boundary conditions in the hyperspherical adiabatic representation have been constructed. We prove that these conditions are asymptotically equivalent to the standard Merkuriev boundary conditions. With these boundary conditions we have formulated the boundary-value problem for Faddeev equations which has the property that the binary channel and the breakup channel are explicitly orthogonal. The effective numerical scheme for solving the formulated boundary-value problem is given.     

Precise measurement of dp elastic scattering at 270 MeV and three-nucleon force effects

The cross section, the deuteron vector A(d)(y) and tensor analyzing powers A(ij), the polarization transfer coefficients K(y('))(ij), and the induced polarization P(y(')) were measured for the dp elastic scattering at 270 MeV. The cross section and A(d)(y) are well reproduced by Faddeev calculations with modern data-equivalent nucleon-nucleon forces plus the Tucson-Melbourne three-nucleon force. In contrast, A(ij), K(y('))(ij), or P(y(')) are not described by such calculations. These facts indicate the deficiencies in the spin dependence of the Tucson-Melbourne force and call for extended three-nucleon force models.     

Axial observables in d-->p--> breakup and the three-nucleon force

We have measured three axial polarization observables in d-->p--> breakup with a polarized 270 MeV deuteron beam on a polarized proton target. Axial observables are zero by parity conservation in elastic scattering but can be easily observed in the breakup channel at the present energy. Based on a symmetry argument, the sensitivity of these observables to the three-nucleon force might be enhanced. Calculations without three-nucleon force are in fair agreement with our measurement, indicating that the expected sensitivity of axial observables to the three-nucleon force is not confirmed. Including a three-nucleon force in the calculation does not improve the agreement with the data.     

Bag-model inspired nucleon-nucleon potentials and the three-nucleon system

Several examples of short-range energy-dependentN-N potentials derived in the quark-compound-bag (QCB) model are presented. They all satisfy the classical causality condition. We show that for radii of theN-N interactions ofb1.4 fm thes-wave QCB potentials reproduce fairly well the trinucleon binding energy and other three-nucleon observables.     

The three-nucleon system with the Reid and Gammel-Brueckner potentials

We report preliminary results for an extension of our calculations to the Reid and Gammel-Brueckner nucleon-nucleon potentials. The results for the Reid potential appear to disagree with those of some other calculations.